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Wu Y, Wang X, Yang L, Kang S, Yan G, Han Y, Fang H, Sun H. Potential of alisols as cancer therapeutic agents: Investigating molecular mechanisms, pharmacokinetics and metabolism. Biomed Pharmacother 2023; 168:115722. [PMID: 37865991 DOI: 10.1016/j.biopha.2023.115722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/11/2023] [Accepted: 10/11/2023] [Indexed: 10/24/2023] Open
Abstract
Albeit remarkable achievements in anti-cancer endeavors, the prevention and treatment of cancer remain unresolved challenges. Hence, there is an urgent need to explore new and efficacious natural compounds with potential anti-cancer therapeutic agents. One such group of compounds is alisols, tetracyclic triterpene alcohols extracted from alisma orientale. Alisols play a significant role in cancer therapy as they can suppress cancer cell proliferation and migration by regulating signaling pathways such as mTOR, Bax/Bcl-2, CHOP, caspase, NF-kB and IRE1. Pharmacokinetic studies showed that alisols can be absorbed entirely, rapidly, and evenly distributed in vivo. Moreover, alisols are low in toxicity and relatively safe to take. Remarkably, each alisol can be converted into many compounds with different pathways to their anti-cancer effects in the body. Thus, alisols are regarded as promising anti-cancer agents with minimal side effects and low drug resistance. This review will examine and discuss alisols' anti-cancer molecular mechanism, pharmacokinetics and metabolism. Based on a comprehensive analysis of nearly 20 years of research, we evaluate the therapeutic potential of alisols for various types of cancer and offer insights and strategies for developing new cancer treatments.
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Affiliation(s)
- Yinqi Wu
- State key laboratory of Integration and Innovation of Classical formula and modern Chinese medicine, National Chinmedomics Research Center, Metabolomics Laboratory, Department of Pharmaceutical Analysis, Heilongjiang University of Chinese Medicine, Heping Road 24, Harbin 150040, China
| | - Xijun Wang
- State key laboratory of Integration and Innovation of Classical formula and modern Chinese medicine, National Chinmedomics Research Center, Metabolomics Laboratory, Department of Pharmaceutical Analysis, Heilongjiang University of Chinese Medicine, Heping Road 24, Harbin 150040, China; State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macau; State Key Laboratory of Dampness Syndrome, The Second Affiliated Hospital Guangzhou University of Chinese Medicine, Dade Road 111, Guangzhou, China.
| | - Le Yang
- State Key Laboratory of Dampness Syndrome, The Second Affiliated Hospital Guangzhou University of Chinese Medicine, Dade Road 111, Guangzhou, China
| | - Shuyu Kang
- State key laboratory of Integration and Innovation of Classical formula and modern Chinese medicine, National Chinmedomics Research Center, Metabolomics Laboratory, Department of Pharmaceutical Analysis, Heilongjiang University of Chinese Medicine, Heping Road 24, Harbin 150040, China
| | - Guangli Yan
- State key laboratory of Integration and Innovation of Classical formula and modern Chinese medicine, National Chinmedomics Research Center, Metabolomics Laboratory, Department of Pharmaceutical Analysis, Heilongjiang University of Chinese Medicine, Heping Road 24, Harbin 150040, China
| | - Ying Han
- State key laboratory of Integration and Innovation of Classical formula and modern Chinese medicine, National Chinmedomics Research Center, Metabolomics Laboratory, Department of Pharmaceutical Analysis, Heilongjiang University of Chinese Medicine, Heping Road 24, Harbin 150040, China
| | - Heng Fang
- State key laboratory of Integration and Innovation of Classical formula and modern Chinese medicine, National Chinmedomics Research Center, Metabolomics Laboratory, Department of Pharmaceutical Analysis, Heilongjiang University of Chinese Medicine, Heping Road 24, Harbin 150040, China
| | - Hui Sun
- State key laboratory of Integration and Innovation of Classical formula and modern Chinese medicine, National Chinmedomics Research Center, Metabolomics Laboratory, Department of Pharmaceutical Analysis, Heilongjiang University of Chinese Medicine, Heping Road 24, Harbin 150040, China.
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2
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Yu W, Liu X, Cai D, Zheng J, Lao B, Huang M, Zhong G. Regional distributions of curcumin and tetrahydrocurcumin in the liver and small intestine of rats when orally co-administered with quercetin and paeoniflorin. Biopharm Drug Dispos 2023; 44:183-191. [PMID: 36638836 DOI: 10.1002/bdd.2346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/27/2022] [Accepted: 12/27/2022] [Indexed: 01/15/2023]
Abstract
Curcumin (CUR), derived from the dietary spice turmeric, is a polyphenolic compound with various biological and pharmacological activities. Tetrahydrocurcumin (THC) is one of the major reductive metabolites of curcumin. A pharmacokinetic study using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for the simultaneous determination of curcumin, THC, quercetin (QR), and paeoniflorin (PF) in rat plasma had been performed. In this study, the regional distributions of curcumin and tetrahydrocurcumin in the liver and the three segments of small intestine (duodenum, jejunum, and ileum) of rats when orally co-administered with quercetin and paeoniflorin were carried out. Drug concentrations were determined using UHPLC-MS/MS. The results showed that curcumin was well distributed in the small intestine, while the distributions of tetrahydrocurcumin in the liver, duodenum, jejunum were similar, but much more abundant in the ileum. When orally co-administered with quercetin and paeoniflorin, the tissue to plasma concentration ratios (Kp values) of curcumin in the three segments of the small intestine were increased, indicating that the presence of quercetin and paeoniflorin increases the distribution of curcumin in these regions. Moreover, the half-life (t1/2 ) of THC in the liver was significantly prolonged, and the Kp value of THC in the liver was increased and the Kp values in the small intestine were decreased, suggesting that the combination of quercetin and paeoniflorin might suppress the metabolism of curcumin in the small intestine. In brief, the combination had an effect on the distributions of curcumin and tetrahydrocurcumin in the liver and small intestine of rats.
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Affiliation(s)
- Weilan Yu
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong Province, China.,Guangzhou Chest Hospital, Guangzhou, Guangdong Province, China
| | - Xiaolin Liu
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong Province, China.,Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Guangzhou, Guangdong Province, China
| | - Dake Cai
- Guangdong Province Engineering Technology Research Institute of Traditional Chinese Medicine, Guangzhou, Guangdong Province, China
| | - Juntao Zheng
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong Province, China.,Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Guangzhou, Guangdong Province, China
| | - Biaochang Lao
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong Province, China.,Hospital of South China University of Technology, Guangzhou, Guangdong Province, China
| | - Min Huang
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong Province, China.,Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Guangzhou, Guangdong Province, China
| | - Guoping Zhong
- Institute of Clinical Pharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong Province, China.,Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, Guangzhou, Guangdong Province, China
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Hens B, Gonzalez-Alvarez I, Bermejo M. Exploring the Predictive Power of the In Situ Perfusion Technique towards Drug Absorption: Theory, Practice, and Applications. Mol Pharm 2022; 19:749-762. [DOI: 10.1021/acs.molpharmaceut.1c00861] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Bart Hens
- Drug Product Design, Pfizer, Sandwich, Kent, CT13 9NJ, United Kingdom
| | - Isabel Gonzalez-Alvarez
- Department Engineering Pharmacy Section, Miguel Hernandez University, San Juan de Alicante, 03550 Alicante, Spain
| | - Marival Bermejo
- Department Engineering Pharmacy Section, Miguel Hernandez University, San Juan de Alicante, 03550 Alicante, Spain
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4
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Rat intestinal drug permeability: A status report and summary of repeated determinations. Eur J Pharm Biopharm 2019; 142:364-376. [DOI: 10.1016/j.ejpb.2019.07.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/28/2019] [Accepted: 07/04/2019] [Indexed: 12/28/2022]
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5
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Wolk O, Markovic M, Porat D, Fine-Shamir N, Zur M, Beig A, Dahan A. Segmental-Dependent Intestinal Drug Permeability: Development and Model Validation of In Silico Predictions Guided by In Vivo Permeability Values. J Pharm Sci 2018; 108:316-325. [PMID: 30055228 DOI: 10.1016/j.xphs.2018.07.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 12/21/2022]
Abstract
The goal of this work was to develop an in silico model that allows predicting segmental-dependent permeability throughout the small intestine (SI). In vivo permeability of 11 model drugs in 3 SI segments (jejunum, mid-SI, ileum) was studied in rats, creating a data set that reflects the conditions throughout the SI. Then, a predictive model was developed, combining physicochemical drug properties influencing the underlying mechanism of passive permeability: Log p, polar surface area, MW, H-bond count, and Log fu, with microenvironmental SI conditions. Excellent correlation was evident between the predicted and experimental data (R2 = 0.914), with similar predictability in each SI segment. Log p and Log fu were identified as the major determinants of permeability, with similar contribution. Total H-bond count was also a significant determinant, followed by polar surface area and MW. Leaving out any of the model parameters decreased its predictability. The model was validated against 5 external drugs, with excellent predictability. Notably, the model was able to predict the segmental-dependent permeability of all drugs showing this trend experimentally. Model predictability was better in the high-permeability versus low-permeability range. Overall, our approach of constructing a straightforward in silico model allowed reliable predictions of segmental-dependent intestinal permeability, providing new insights into relative effects of drug-related factors and gastrointestinal environment on permeability.
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Affiliation(s)
- Omri Wolk
- Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Milica Markovic
- Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Daniel Porat
- Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Noa Fine-Shamir
- Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Moran Zur
- Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Avital Beig
- Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Arik Dahan
- Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
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Abstract
INTRODUCTION In pharmacotherapy, drugs are mostly taken orally to be absorbed systemically from the small intestine, and some drugs are known to have preferential absorption sites in the small intestine. It would therefore be valuable to know the absorption sites of orally administered drugs and the influencing factors. Areas covered:In this review, the author summarizes the reported absorption sites of orally administered drugs, as well as, influencing factors and experimental techniques. Information on the main absorption sites and influencing factors can help to develop ideal drug delivery systems and more effective pharmacotherapies. Expert opinion: Various factors including: the solubility, lipophilicity, luminal concentration, pKa value, transporter substrate specificity, transporter expression, luminal fluid pH, gastrointestinal transit time, and intestinal metabolism determine the site-dependent intestinal absorption. However, most of the dissolved fraction of orally administered drugs including substrates for ABC and SLC transporters, except for some weakly basic drugs with higher pKa values, are considered to be absorbed sequentially from the proximal small intestine. Securing the solubility and stability of drugs prior to reaching to the main absorption sites and appropriate delivery rates of drugs at absorption sites are important goals for achieving effective pharmacotherapy.
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Affiliation(s)
- Teruo Murakami
- a Laboratory of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmaceutical Sciences , Hiroshima International University , Hiroshima , Japan
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7
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Peters SA, Jones CR, Ungell AL, Hatley OJD. Predicting Drug Extraction in the Human Gut Wall: Assessing Contributions from Drug Metabolizing Enzymes and Transporter Proteins using Preclinical Models. Clin Pharmacokinet 2016; 55:673-96. [PMID: 26895020 PMCID: PMC4875961 DOI: 10.1007/s40262-015-0351-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Intestinal metabolism can limit oral bioavailability of drugs and increase the risk of drug interactions. It is therefore important to be able to predict and quantify it in drug discovery and early development. In recent years, a plethora of models-in vivo, in situ and in vitro-have been discussed in the literature. The primary objective of this review is to summarize the current knowledge in the quantitative prediction of gut-wall metabolism. As well as discussing the successes of current models for intestinal metabolism, the challenges in the establishment of good preclinical models are highlighted, including species differences in the isoforms; regional abundances and activities of drug metabolizing enzymes; the interplay of enzyme-transporter proteins; and lack of knowledge on enzyme abundances and availability of empirical scaling factors. Due to its broad specificity and high abundance in the intestine, CYP3A is the enzyme that is frequently implicated in human gut metabolism and is therefore the major focus of this review. A strategy to assess the impact of gut wall metabolism on oral bioavailability during drug discovery and early development phases is presented. Current gaps in the mechanistic understanding and the prediction of gut metabolism are highlighted, with suggestions on how they can be overcome in the future.
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Affiliation(s)
- Sheila Annie Peters
- Translational Quantitative Pharmacology, BioPharma, R&D Global Early Development, Merck KGaA, Frankfurter Str. 250, F130/005, 64293, Darmstadt, Germany.
| | | | - Anna-Lena Ungell
- Investigative ADME, Non-Clinical Development, UCB New Medicines, BioPharma SPRL, Braine l'Alleud, Belgium
| | - Oliver J D Hatley
- Simcyp Limited (A Certara Company), Blades Enterprise Centre, Sheffield, UK
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Varma MV, Pang KS, Isoherranen N, Zhao P. Dealing with the complex drug-drug interactions: Towards mechanistic models. Biopharm Drug Dispos 2015; 36:71-92. [DOI: 10.1002/bdd.1934] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 12/11/2014] [Accepted: 12/14/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Manthena V. Varma
- Pharmacokinetics, Dynamics and Metabolism; Pfizer Inc; Groton Connecticut USA
| | - K. Sandy Pang
- Leslie Dan Faculty of Pharmacy; University of Toronto; M5S 3M2 Canada
| | - Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy; University of Washington; Seattle WA USA
| | - Ping Zhao
- Division of Pharmacometrics, Office of Clinical Pharmacology/Office of Translational Sciences; Center for Drug Evaluation and Research, US Food and Drug Administration; Silver Spring MD USA
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9
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Stappaerts J, Brouwers J, Annaert P, Augustijns P. In situ perfusion in rodents to explore intestinal drug absorption: challenges and opportunities. Int J Pharm 2014; 478:665-81. [PMID: 25448559 DOI: 10.1016/j.ijpharm.2014.11.035] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/13/2014] [Accepted: 11/14/2014] [Indexed: 12/13/2022]
Abstract
The in situ intestinal perfusion technique in rodents is a very important absorption model, not only because of its predictive value, but it is also very suitable to unravel the mechanisms underlying intestinal drug absorption. This literature overview covers a number of specific applications for which the in situ intestinal perfusion set-up can be applied in favor of established in vitro absorption tools, such as the Caco-2 cell model. Qualities including the expression of drug transporters and metabolizing enzymes relevant for human intestinal absorption and compatibility with complex solvent systems render the in situ technique the most designated absorption model to perform transporter-metabolism studies or to evaluate the intestinal absorption from biorelevant media. Over the years, the in situ intestinal perfusion model has exhibited an exceptional ability to adapt to the latest challenges in drug absorption profiling. For instance, the introduction of the mesenteric vein cannulation allows determining the appearance of compounds in the blood and is of great use, especially when evaluating the absorption of compounds undergoing intestinal metabolism. Moreover, the use of the closed loop intestinal perfusion set-up is interesting when compounds or perfusion media are scarce. Compatibility with emerging trends in pharmaceutical profiling, such as the use of knockout or transgenic animals, generates unparalleled possibilities to gain mechanistic insight into specific absorption processes. Notwithstanding the fact that the in situ experiments are technically challenging and relatively time-consuming, the model offers great opportunities to gain insight into the processes determining intestinal drug absorption.
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Affiliation(s)
- Jef Stappaerts
- Drug Delivery and Disposition, KU Leuven Department of Pharmaceutical and Pharmacological Sciences, Leuven, Belgium
| | - Joachim Brouwers
- Drug Delivery and Disposition, KU Leuven Department of Pharmaceutical and Pharmacological Sciences, Leuven, Belgium
| | - Pieter Annaert
- Drug Delivery and Disposition, KU Leuven Department of Pharmaceutical and Pharmacological Sciences, Leuven, Belgium
| | - Patrick Augustijns
- Drug Delivery and Disposition, KU Leuven Department of Pharmaceutical and Pharmacological Sciences, Leuven, Belgium.
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10
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Zhao G, Huang J, Xue K, Si L, Li G. Enhanced intestinal absorption of etoposide by self-microemulsifying drug delivery systems: Roles of P-glycoprotein and cytochrome P450 3A inhibition. Eur J Pharm Sci 2013; 50:429-39. [DOI: 10.1016/j.ejps.2013.08.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 07/16/2013] [Accepted: 08/10/2013] [Indexed: 12/20/2022]
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11
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Site dependent intestinal absorption of darunavir and its interaction with ketoconazole. Eur J Pharm Sci 2013; 49:51-6. [DOI: 10.1016/j.ejps.2013.01.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 12/18/2012] [Accepted: 01/30/2013] [Indexed: 01/30/2023]
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12
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Fairstein M, Swissa R, Dahan A. Regional-dependent intestinal permeability and BCS classification: elucidation of pH-related complexity in rats using pseudoephedrine. AAPS JOURNAL 2013; 15:589-97. [PMID: 23440549 DOI: 10.1208/s12248-013-9462-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 01/30/2013] [Indexed: 12/19/2022]
Abstract
Based on its lower Log P value relative to metoprolol, a marker for the low/high-permeability (P(eff)) class boundary, pseudoephedrine was provisionally classified as BCS low-permeability compound. On the other hand, following oral administration, pseudoephedrine fraction dose absorbed (F(abs)) and systemic bioavailability approaches 100%. This represents a challenge to the generally recognized P(eff)-F(abs) correlation. The purpose of this study was to elucidate the underlying mechanisms behind the confusion in pseudoephedrine's BCS classification. Pseudoephedrine's BCS solubility class was determined, and its physicochemical properties and intestinal permeability were thoroughly investigated, both in vitro and in vivo in rats, considering the complexity of the whole of the small intestine. Pseudoephedrine was found to be unequivocally a high-solubility compound. All of the permeability studies revealed similar phenomenon; at any given intestinal segment/pH, the permeability of metoprolol was higher than that of pseudoephedrine, however, as the intestinal region becomes progressively distal, and the pH gradually increases, pseudoephedrine's permeability rises above that of metoprolol in the former segment. This unique permeability pattern likely explains pseudoephedrine's complete absorption. In conclusion, pseudoephedrine is a BCS Class I compound; no discrepancy between P(eff) and F(abs) is involved in its absorption. Rather, it reflects the complexity behind P(eff) when considering the whole of the intestine. We propose to allow high-permeability classification to drugs with P(eff) that matches/exceeds the low/high class benchmark anywhere throughout the intestinal tract and not restricted necessarily to the jejunum.
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Affiliation(s)
- Moran Fairstein
- Department of Clinical Pharmacology, School of Pharmacy, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 653 Beer-Sheva 84105, Israel
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13
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Dufek MB, Knight BM, Bridges AS, Thakker DR. P-Glycoprotein Increases Portal Bioavailability of Loperamide in Mouse by Reducing First-Pass Intestinal Metabolism. Drug Metab Dispos 2013; 41:642-50. [DOI: 10.1124/dmd.112.049965] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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14
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Oga EF, Sekine S, Horie T. Ex Vivo and In Vivo Investigations of the Effects of Extracts of Vernonia amygdalina, Carica papaya and Tapinanthus sessilifolius on Digoxin Transport and Pharmacokinetics: Assessing the Significance on Rat Intestinal P-glycoprotein Efflux. Drug Metab Pharmacokinet 2013; 28:314-20. [DOI: 10.2133/dmpk.dmpk-12-rg-117] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Fasinu P, Pillay V, Ndesendo VMK, du Toit LC, Choonara YE. Diverse approaches for the enhancement of oral drug bioavailability. Biopharm Drug Dispos 2011; 32:185-209. [PMID: 21480294 DOI: 10.1002/bdd.750] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 11/23/2010] [Accepted: 01/28/2011] [Indexed: 12/31/2022]
Abstract
In conscious and co-operating patients, oral drug delivery remains the preferable route of drug administration. However, not all drugs possess the desirable physicochemical and pharmacokinetic properties which favor oral administration mainly due to poor bioavailability. This has in some cases led to the choice of other routes of administration, which may compromise the convenience and increase the risk of non-compliance. Poor bioavailability has necessitated the administration of higher than normally required oral doses which often leads to economic wastages, risk of toxicity, erratic and unpredictable responses. The challenge over the years has been to design techniques that will allow oral administration of most drugs, irrespective of their properties, to achieve a therapeutic systemic availability. This will be a worthy achievement since over 90% of therapeutic compounds are known to possess oral bioavailability limitations. In this review, an attempt has been made to explore various approaches that have been used in recent years to improve oral drug bioavailability, including physical and chemical means. This review strives to provide a comprehensive overview of advances made over the past 10 years (2000-2010) in the improvement of the oral bioavailability of drugs. Briefly, the design of prodrugs to bypass metabolism or to enhance solubility as well as modification of formulation techniques such as the use of additives, permeation enhancers, solubilizers, emulsifiers and non-aqueous vehicles have been discussed. Arising approaches, such as formulation modification techniques; novel drug delivery systems, which exploit the gastrointestinal regionality of drugs, and include the pharmaceutical application of nanotechnology as an emerging area in drug delivery; inhibition of efflux pumps; and inhibition of presystemic metabolism have been more extensively addressed. This critical review sought to assess each method aimed at enhancing the oral bioavailability of drugs in terms of the purpose, scientific basis, limitations, commercial application, as well as the areas in which current research efforts are being focused and should be focused in the future.
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Affiliation(s)
- Pius Fasinu
- Department of Pharmacy and Pharmacology, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, South Africa
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16
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Pang KS, Morris ME, Sun H. Formed and preformed metabolites: facts and comparisons. J Pharm Pharmacol 2010; 60:1247-75. [DOI: 10.1211/jpp.60.10.0001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abstract
The administration of metabolites arising from new drug entities is often employed in drug discovery to investigate their associated toxicity. It is expected that administration of metabolites can predict the exposure of metabolites originating from the administration of precursor drug. Whether exact and meaningful information can be obtained from this has been a topic of debate. This communication summarizes observations and theoretical relationships based on physiological modelling for the liver, kidney and intestine, three major eliminating organs/tissues. Theoretical solutions based on physiological modelling of organs were solved, and the results suggest that deviations are expected. Here, examples of metabolite kinetics observed mostly in perfused organs that did not match predictions are provided. For the liver, discrepancies in fate between formed and preformed metabolites may be explained by the heterogeneity of enzymes, the presence of membrane barriers and whether transporters are involved. For the kidney, differences have been attributed to glomerular filtration of the preformed but not the formed metabolite. For the intestine, the complexity of segregated flows to the enterocyte and serosal layers and differences in metabolism due to the route of administration are addressed. Administration of the metabolite may or may not directly reflect the toxicity associated with drug use. However, kinetic data on the preformed metabolite will be extremely useful to develop a sound model for modelling and simulations; in-vitro evidence on metabolite handling at the target organ is also paramount. Subsequent modelling and simulation of metabolite data arising from a combined model based on both drug and preformed metabolite data are needed to improve predictions on the behaviours of formed metabolites.
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Affiliation(s)
- K Sandy Pang
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, M5S 3M2, Canada
| | - Marilyn E Morris
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Amherst, NY 14260, USA
| | - Huadong Sun
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, M5S 3M2, Canada
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Pereira de Oliveira M, Olivier JC, Pariat C, Roche D, Greiner J, Vierling P, Couet W. Investigation of oral bioavailability and brain distribution of the Ind(8)-Val conjugate of indinavir in rodents. J Pharm Pharmacol 2010; 57:453-8. [PMID: 15831205 DOI: 10.1211/0022357055786] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
Protease inhibitors are successfully used for the treatment of acquired immune deficiency syndrome (AIDS) although their biopharmaceutical characteristics are not optimal. Prodrugs have therefore been synthesized to increase protease inhibitor bioavailability and brain distribution. Among several compounds tested, a valine derivative of indinavir (Ind(8)-Val) showed promising characteristics using an in-vitro Caco-2 cell model. The objective of this study was to further investigate this compound using in-situ and in-vivo approaches. The pharmacokinetics of indinavir (Ind) and Ind(8)-Val were investigated in rats after intravenous and oral administration. Free indinavir resulting from in-vivo hydrolysis of Ind(8)-Val could not be detected in the plasma of rats receiving Ind(8)-Val. Furthermore Ind(8)-Val bioavailability was only 32% on average compared with 76% for indinavir, and effective permeability coefficients determined with a single-pass intestinal perfusion method were close to 25 times 106 cms−1 for the two compounds. Brain-to-plasma concentration ratios in the post equilibrium phase after intravenous administration to mice were 9.7 ± 8.1% for indinavir and 2.5 ± 2.7% for Ind(8)-Val. In conclusion, the promising biopharmaceutical characteristics of Ind(8)-Val suggested from previous in-vitro experiments with the Caco-2 cell model were not confirmed by in-situ and in-vivo experiments.
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Affiliation(s)
- Manuela Pereira de Oliveira
- EA3809 Pharmacologie des Agents Anti-Infectieux, Faculté de Médecine & Pharmacie, 86005 Poitiers Cedex, France
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Petri N, Lennernäs H. In Vivo
Permeability Studies in the Gastrointestinal Tract of Humans. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/9783527623860.ch9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Dahan A, Amidon GL. Segmental dependent transport of low permeability compounds along the small intestine due to P-glycoprotein: the role of efflux transport in the oral absorption of BCS class III drugs. Mol Pharm 2009; 6:19-28. [PMID: 19248230 DOI: 10.1021/mp800088f] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The purpose of this study was to investigate the role of P-gp efflux in the in vivo intestinal absorption process of BCS class III P-gp substrates, i.e. high-solubility low-permeability drugs. The in vivo permeability of two H (2)-antagonists, cimetidine and famotidine, was determined by the single-pass intestinal perfusion model in different regions of the rat small intestine, in the presence or absence of the P-gp inhibitor verapamil. The apical to basolateral (AP-BL) and the BL-AP transport of the compounds in the presence or absence of various efflux transporters inhibitors (verapamil, erythromycin, quinidine, MK-571 and fumitremorgin C) was investigated across Caco-2 cell monolayers. P-gp expression levels in the different intestinal segments were confirmed by immunoblotting. Cimetidine and famotidine exhibited segmental dependent permeability through the gut wall, with decreased P(eff) in the distal ileum in comparison to the proximal regions of the intestine. Coperfusion of verapamil with the drugs significantly increased the permeability in the ileum, while no significant change in the jejunal permeability was observed. Both drugs exhibited significantly greater BL-AP than AP-BL Caco-2 permeability, indicative of net mucosal secretion. Concentration dependent decrease of this secretion was obtained by the P-gp inhibitors verapamil, erythromycin and quinidine, while no effect was evident by the MRP2 inhibitor MK-571 and the BCRP inhibitor FTC, indicating that P-gp is the transporter mediates the intestinal efflux of cimetidine and famotidine. P-gp levels throughout the intestine were inversely related to the in vivo permeability of the drugs from the different segments. The data demonstrate that for these high-solubility low-permeability P-gp substrates, P-gp limits in vivo intestinal absorption in the distal segments of the small intestine; however P-gp plays a minimal role in the proximal intestinal segments due to significant lower P-gp expression levels in this region.
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Affiliation(s)
- Arik Dahan
- College of Pharmacy, The University of Michigan, Ann Arbor, Michigan 48109-1065, USA
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20
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Dahan A, West BT, Amidon GL. Segmental-dependent membrane permeability along the intestine following oral drug administration: Evaluation of a triple single-pass intestinal perfusion (TSPIP) approach in the rat. Eur J Pharm Sci 2008; 36:320-9. [PMID: 19028572 DOI: 10.1016/j.ejps.2008.10.013] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 10/06/2008] [Accepted: 10/17/2008] [Indexed: 11/20/2022]
Abstract
In this paper we evaluate a modified approach to the traditional single-pass intestinal perfusion (SPIP) rat model in investigating segmental-dependent permeability along the intestine following oral drug administration. Whereas in the traditional model one single segment of the intestine is perfused, we have simultaneously perfused three individual segments of each rat intestine: proximal jejunum, mid-small intestine and distal ileum, enabling to obtain tripled data from each rat compared to the traditional model. Three drugs, with different permeabilities, were utilized to evaluate the model: metoprolol, propranolol and cimetidine. Data was evaluated in comparison to the traditional method. Metoprolol and propranolol showed similar P(eff) values in the modified model in all segments. Segmental-dependent permeability was obtained for cimetidine, with lower P(eff) in the distal parts. Similar P(eff) values for all drugs were obtained in the traditional method, illustrating that the modified model is as accurate as the traditional, throughout a wide range of permeability characteristics, whether the permeability is constant or segment-dependent along the intestine. Three-fold higher statistical power to detect segmental-dependency was obtained in the modified approach, as each subject serves as his own control. In conclusion, the Triple SPIP model can reduce the number of animals utilized in segmental-dependent permeability research without compromising the quality of the data obtained.
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Affiliation(s)
- Arik Dahan
- University of Michigan, College of Pharmacy, 428 Church Street, Ann Arbor, MI 48109-1065, USA
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21
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Pang KS. Safety testing of metabolites: Expectations and outcomes. Chem Biol Interact 2008; 179:45-59. [PMID: 18926805 DOI: 10.1016/j.cbi.2008.09.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 09/12/2008] [Accepted: 09/15/2008] [Indexed: 12/18/2022]
Abstract
Metabolites arising from chemical entities, old or new, are often mediators of toxicity. Frequently, metabolites are investigated in test animals, with the expectation that the resultant toxicity or activity will mimic the exposure of their formed counterparts. This communication described observations that showed discrepant kinetics between formed and preformed metabolites in the liver, intestine, and kidney, major drug removal organs. Differences in the observed areas under the curve (AUCs) or the extraction ratios (Es) of formed and preformed metabolites in the liver had been attributed to zonal, enzyme heterogeneity, membrane barriers, or transporters. Preformed and formed metabolite also differed in their handling by the kidney; only the preformed and not the formed metabolite would be filtered. In the intestine, differences in the absorption of the precursor and the metabolite and the flow pattern in the intestine would bring about discrepancy in the time-courses of the formed vs. preformed metabolites. Analytical solutions of the AUCs of the metabolites and extraction ratios, based on physiological modeling of the liver, kidney, and intestine, showed that the AUC of the preformed, administered metabolite was dependent only on metabolite parameters, whereas the AUC of the formed metabolite was modulated additionally by the metabolic, secretory and intestinal absorptive intrinsic clearances of the precursor drug. Hence, administration of the synthetic metabolite would not reflect the toxicity associated with the metabolite formed via bioactivation. However, data on preformed metabolite may be used for simultaneous fitting by a combined model of drug and metabolite. Such a strategy is shown to be successful in risk assessment of environmental chemicals. Upon refinement of the resultant model with data on metabolite transport and handling by modeling and simulations, the resultant model would be more robust to provide improved predictions on metabolite toxicity pursuant to drug administration.
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Eriksson U, Peterson LW, Kashemirov BA, Hilfinger JM, Drach JC, Borysko KZ, Breitenbach JM, Kim JS, Mitchell S, Kijek P, McKenna CE. Serine peptide phosphoester prodrugs of cyclic cidofovir: synthesis, transport, and antiviral activity. Mol Pharm 2008; 5:598-609. [PMID: 18481868 DOI: 10.1021/mp8000099] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cidofovir (HPMPC, 1), a broad-spectrum antiviral agent, is currently used to treat AIDS-related human cytomegalovirus (HCMV) retinitis and has recognized therapeutic potential for orthopox virus infections, but is limited by its low oral bioavailability. Cyclic cidofovir (2) displays decreased nephrotoxicity compared to 1, while also exhibiting potent antiviral activity. Here we describe in detail the synthesis and evaluation as prodrugs of four cHPMPC dipeptide conjugates in which the free POH of 2 is esterified by the Ser side chain alcohol group of an X-L-Ser(OMe) dipeptide: 3 (X=L-Ala), 4 (X=L-Val), 5 (X=L-Leu), and 6 (X=L-Phe). Perfusion studies in the rat establish that the mesenteric permeability to 4 is more than 20-fold greater than to 1, and the bioavailability of 4 is increased 6-fold relative to 1 in an in vivo murine model. In gastrointestinal and liver homogenates, the cHPMPC prodrugs are rapidly hydrolyzed to 2. Prodrugs 3, 4, and 5 are nontoxic at 100 microM in HFF and KB cells and in cell-based plaque reduction assays had IC 50 values of 0.1-0.5 microM for HCMV and 10 microM for two orthopox viruses (vaccinia and cowpox). The enhanced transport properties of 3-6, conferred by incorporation of a biologically benign dipeptide moiety, and the facile cleavage of the Ser-O-P linkage suggest that these prodrugs represent a promising new approach to enhancing the bioavailability of 2.
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Affiliation(s)
- Ulrika Eriksson
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0744, USA
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Wang J, Urban L, Bojanic D. Maximising use ofin vitroADMET tools to predictin vivobioavailability and safety. Expert Opin Drug Metab Toxicol 2007; 3:641-65. [DOI: 10.1517/17425255.3.5.641] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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24
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Uno S, Kawase A, Tsuji A, Tanino T, Iwaki M. Decreased intestinal CYP3A and P-glycoprotein activities in rats with adjuvant arthritis. Drug Metab Pharmacokinet 2007; 22:313-21. [PMID: 17827786 DOI: 10.2133/dmpk.22.313] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Adjuvant-induced arthritis (AA) rats have been used as an animal model for rheumatoid arthritis. Several studies have shown that the pharmacokinetics of a number of drugs are altered in AA rats. We investigated the effects of AA on the barrier functions of the intestine using a rat model. Intestinal CYP3A activities (midazolam 1'-hydroxylation and 7-benzyloxy-4-(trifluoromethyl)-coumarin 7-hydroxylation) in AA rats were significantly decreased compared with those in normal rats, with marked decrease observed in the upper segment of intestine. Intestinal P-glycoprotein (P-gp) activity at upper segment was also significantly decreased in AA rats to 60% of that in normal rats, and the other segments (middle and lower) of intestine also exhibited tendencies toward decrease in P-gp activity. This decrease was supported by the finding that levels of mdr1a mRNA and P-gp protein were decreased in AA rats. No significant differences were observed in intestinal paracellular and transcellular permeability between AA and normal rats. These results suggest that intestinal CYP3A and P-gp activities are decreased in AA rats, and that the pharmacokinetics and bioavailabilities of drugs whose membrane permeation is limited by intestinal CYP3A and/or P-gp may be altered in rheumatic diseases.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B/metabolism
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP-Binding Cassette Transporters/metabolism
- Animals
- Antipyrine/metabolism
- Arthritis, Experimental/metabolism
- Blotting, Western
- Chromatography, High Pressure Liquid
- Cytochrome P-450 CYP3A/metabolism
- Diffusion Chambers, Culture
- Female
- Fluorescent Dyes
- In Vitro Techniques
- Intestinal Mucosa/metabolism
- Intestines/enzymology
- Microsomes/drug effects
- Microsomes/enzymology
- Microsomes/metabolism
- Midazolam/metabolism
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Ranitidine/pharmacokinetics
- Rats
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
- Rhodamine 123
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Affiliation(s)
- Satoshi Uno
- Department of Pharmacy, Kinki University, Osaka, Japan
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25
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Pang KS, Weiss M, Macheras P. Advanced pharmacokinetic models based on organ clearance, circulatory, and fractal concepts. AAPS J 2007; 9:E268-83. [PMID: 17907768 PMCID: PMC2751417 DOI: 10.1208/aapsj0902030] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Accepted: 05/14/2007] [Indexed: 12/22/2022] Open
Abstract
Three advanced models of pharmacokinetics are described. In the first class are physiologically based pharmacokinetic models based on in vitro data on transport and metabolism. The information is translated as transporter and enzyme activities and their attendant heterogeneities into liver and intestine models. Second are circulatory models based on transit time distribution and plasma concentration time curves. The third are fractal models for nonhomogeneous systems and non-Fickian processes are presented. The usefulness of these pharmacokinetic models, with examples, is compared.
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Affiliation(s)
- K Sandy Pang
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, Canada M5S 3M2.
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Solas C, Simon N, Drogoul MP, Quaranta S, Frixon-Marin V, Bourgarel-Rey V, Brunet C, Gastaut JA, Durand A, Lacarelle B, Poizot-Martin I. Minimal effect of MDR1 and CYP3A5 genetic polymorphisms on the pharmacokinetics of indinavir in HIV-infected patients. Br J Clin Pharmacol 2007; 64:353-62. [PMID: 17517050 PMCID: PMC2000655 DOI: 10.1111/j.1365-2125.2007.02903.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
AIMS The protease inhibitor indinavir is characterized by an important interindividual pharmacokinetic variability, which results from the actions of the metabolizing enzymes cytochrome P450 (CYP) 3A and the multidrug efflux pump P-glycoprotein (P-gp), encoded by MDR1. Using a population pharmacokinetic approach, we investigated the effect of several MDR1 and CYP3A5 polymorphisms on the pharmacokinetic parameters of indinavir in HIV-infected patients. METHODS Twenty-eight patients receiving indinavir alone or together with ritonavir were included. Indinavir pharmacokinetics were studied over a 12 h interval. Genetic polymorphisms were assessed by real-time PCR assays and direct sequencing for MDR1 and by PCR-SSCP analysis for CYP3A5. RESULTS The pharmacokinetics of indinavir were best described by a one-compartment model with first-order absorption. In the final model, the MDR1 C3435T genotype and ritonavir were identified as statistically significant covariates (P </= 0.001) for the absorption rate constant (95% confidence interval on the difference between CC and CT genotype 0.37, 5.53) and for clearance (95% confidence interval on the difference 5.8, 26.2), respectively. Patients with the CYP3A5*3/*3 genotype receiving indinavir alone had a 31% decrease in the indinavir clearance rate compared with patients carrying the CYP3A5*1/*3 genotype. CONCLUSIONS The MDR1 C3435T genotype affects the absorption constant of indinavir suggesting that P-gp may be implicated in its pharmacokinetic variability. Through its inhibition of CYP3A and P-gp, ritonavir could attenuate the pharmacokinetic variability linked to genetic differences, reducing significantly the interindividual variability of indinavir. However, genotyping MDR1 and/or CYP3A5 to optimize protease inhibitor boosted regimens does not seem clinically relevant.
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Affiliation(s)
- Caroline Solas
- Fédération de Pharmacologie, AP-HM Hôpital La Timone, and Unité FRE-CNRS 2737, Faculté de Pharmacie, AP-HM Hôpital de la Conception, Marseille, France.
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Nishimura T, Amano N, Kubo Y, Ono M, Kato Y, Fujita H, Kimura Y, Tsuji A. Asymmetric Intestinal First-Pass Metabolism Causes Minimal Oral Bioavailability of Midazolam in Cynomolgus Monkey. Drug Metab Dispos 2007; 35:1275-84. [PMID: 17470527 DOI: 10.1124/dmd.106.013037] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Oral bioavailability of some drugs is substantially lower in cynomolgus monkeys than in various other species, including humans. In the present study, midazolam was used as a model drug to investigate the reason for the lower bioavailability in these monkeys. The bioavailability of midazolam after oral administration was minimal in monkeys and rats, being only 2.1 and 1.1%, respectively. In monkeys, this low bioavailability could not be explained simply in terms of a hepatic first-pass effect. To examine the roles of intestinal metabolism and transport, we evaluated apical-to-basal and basal-to-apical transport of midazolam, and the formation of metabolites in small intestinal tissues using an Ussing-type chamber. The values of mucosal extraction ratio were estimated to be 0.97, 0.93, and 0.89 during apical-to-basal transport in the upper, middle, and lower small intestine of monkeys, respectively, whereas the corresponding values for rats were close to zero, indicating that extensive metabolism of midazolam occurs, particularly in the upper region of the small intestine in monkeys, but not rats. Interestingly, formation of the metabolites was much greater during transport in the apical-to-basal direction than in the basal-to-apical direction, and this could be well explained by a mathematical model based on the assumption that extensive metabolism is associated with the uptake process of midazolam from the apical cell surface. Thus, we conclude that an asymmetric distribution of metabolic activity in the small intestine, leading to extensive metabolism during uptake from the apical cell surface, accounts for the minimal oral bioavailability of midazolam in cynomolgus monkeys.
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Affiliation(s)
- Tomohiro Nishimura
- Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan
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Acott PD, Crocker JF, Renton KW. Evaluation of performance factors affecting two formulations of cyclosporine in pediatric renal transplant patients. Transplant Proc 2007; 38:2835-41. [PMID: 17112843 DOI: 10.1016/j.transproceed.2006.08.096] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Indexed: 01/28/2023]
Abstract
Success of renal transplantation in children is largely due to improvements in immunosuppressant therapy since the introduction of calcineurin inhibitors. The aim of this study was to identify possible factors that result in formulation differences in the exposure of pediatric patients to cyclosporine (CsA). We examined the handling of the two major formulations of CsA in a group of pediatric renal transplant recipients. The pharmacokinetic profiles of both formulations were assessed, and the data stratified to assess the effects of age, gender, time posttransplant, and other concomitant drug therapy on the two CsA formulations. The microemulsified formulation (MEC) enhanced bioavailability compared to the older oil-based formulation (CYA), especially at C2, with more predictable and consistent absorption in children. This higher bioavailability allowed a 15% reduction of dosing to achieve equal drug exposure. The concentration achieved by MEC at C2 demonstrated a much higher correlation with area under the concentration curve (AUC) than the concentration at C0. In the case of CYA a strong correlation was obtained between AUC and the concentrations obtained at both C0 and C2. Calcium channel blockers increased AUC(0-8) for both CsA formulations. Norfloxacin and pravastatin cotreatment had no effect on either of the CsA formulations. In contrast, the bioavailability of CsA was increased in boys using MEC formulation but this gender-based difference was absent during the use of CYA. This suggests that caution is required for introduction of new formulations of drugs to pediatric patients to evaluate differential effects of age, gender, and concomitant drug therapy.
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Affiliation(s)
- P D Acott
- Dalhousie University, Department of Pediatrics, IWK Health Center, Halifax, Nova Scotia, Canada.
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29
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Kaddoumi A, Fleisher D, Heimbach T, Li LY, Cole S. Factors influencing regional differences in intestinal absorption of UK-343,664 in rat: Possible role in dose-dependent pharmacokinetics. J Pharm Sci 2006; 95:435-45. [PMID: 16381015 DOI: 10.1002/jps.20527] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this study was to evaluate potential contributions of intestinal export and metabolism to the oral dose-dependent pharmacokinetics of the human cGMP-specific phosphodiesterase type 5 inhibitor, UK-343,664. Differences between jejunal and ileal handling of this CYP3A and P-gp substrate were investigated. CYP3A and P-gp display differing activities in the upper and lower mammalian small intestine and their impact on variable drug absorption can be mechanistically assessed for individual compounds with in situ perfusion of rat's small intestine. Isolated segments of rat jejunum and ileum were perfused with UK-343,664 solution and measurements were made as a function of drug concentration for dose dependence and in the presence of CYP3A and P-gp inhibitors. Intestinal permeability and metabolism were measured by total drug disappearance and major metabolite, UK-347,334 (N-desethyl metabolite), appearance in the intestinal lumen. Intestinal tissue and mesenteric blood measurements of drug and metabolite were also determined. The effective permeability (P(eff)) of UK-343,664 and metabolite formation (F(met)) increased as a function of concentration. Regional differences in P(eff) and F(met) were observed with low-intestinal metabolism of UK-343,664 in both regions (<10%). P-gp inhibition caused significant increase in P(eff) and F(met) in jejunum and ileum while ketoconazole, a P-gp and CYP3A inhibitor, has only limited effect on metabolism. In conclusion, UK-343,664 absorption is mainly regulated by P-gp in jejunum and ileum while CYP3A intestinal metabolism has minimal effect. This role of P-gp could explain the dose-dependent pharmacokinetics of UK-343,664 and its unusual behavior of t(max) as a function of dose.
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Affiliation(s)
- Amal Kaddoumi
- School of Pharmacy, University of Washington, Seattle, 98195-7610, USA.
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Pereira de Oliveira M, Venisse N, Couet W, Olivier JC. LC–MS/MS determination of the HIV-1 protease inhibitor indinavir in brain and testis of mice. J Pharm Biomed Anal 2006; 40:353-9. [PMID: 16112534 DOI: 10.1016/j.jpba.2005.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 07/07/2005] [Accepted: 07/07/2005] [Indexed: 11/22/2022]
Abstract
A rapid and sensitive method for the determination of indinavir in mice brain and testis is described and validation data are provided. Indinavir and the internal standard (IS) amprenavir were isolated from homogenized tissue matrices using a mixed-mode solid-phase extraction (SPE) procedure and were then analyzed by reversed-phase liquid chromatography/tandem mass spectrometry (LC-MS/MS). The mass spectrometer in the positive-ion multiple reaction monitoring mode used pairs of ions at m/z of 614.1/421.3 for indinavir and of 506.1/245.3 for IS. The calibration curves were linear over the range 0.0012-0.0390 micromol/kg for brain and 0.39-12.50 micromol/kg for testis. Linearity, repeatability and accuracy were validated. The applicability of the method was demonstrated by assessing indinavir in brain and testis of three mice dosed with intravenous bolus administration of indinavir (16.3 micromol/kg).
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Affiliation(s)
- Manuela Pereira de Oliveira
- Pharmacologie des Médicaments Anti-Infectieux, Pôle Biologie-Santé, Faculté de Médecine & Pharmacie, 40 av. du Recteur Pineau, 86022 Poitiers Cedex, France
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Pereira de Oliveira M, Garcion E, Venisse N, Benoit JP, Couet W, Olivier JC. Tissue distribution of indinavir administered as solid lipid nanocapsule formulation in mdr1a (+/+) and mdr1a (-/-) CF-1 mice. Pharm Res 2005; 22:1898-1905. [PMID: 16132350 DOI: 10.1007/s11095-005-7147-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2005] [Revised: 05/14/2006] [Accepted: 05/14/2005] [Indexed: 02/05/2023]
Abstract
PURPOSE Due to protease inhibitor (PI) efflux transport by P-glycoprotein (P-gp), insufficient PI concentrations result in low ongoing HIV replication in the so-called virus sanctuaries (brain and testes). The aim of the present study was to evaluate indinavir-loaded nanocapsules (Ind-LNC) including Solutol HS15, an excipient reported to possess in vitro P-gp inhibiting properties, as a means to improve indinavir distribution into brain and testes of mice. METHODS Normal mdr1a (+/+) or P-gp-deficient mdr1a (-/-) CF-1 mice were dosed with Ind-LNC (10 mg indinavir/kg, i.v.). At 30 min post-administration, indinavir was determined in plasma, brain, testes, as well as in kidneys, liver, and heart by LC-MS/MS, and tissue/plasma concentration ratios were calculated. Results were compared with those of control groups that received an indinavir solution (Ind-Sol). RESULTS Using Ind-Sol, ratios were 21.3- and 3.3-fold higher in brains and testes of mdr1a (-/-) mice than of mdr1a (+/+) mice, respectively, whereas in the other organs ratios were not significantly different between the two substrains. When Ind-LNC was used, a similar [mdr1a(-/-) vs. mdr1a (+/+) mice] trend was observed. Moreover, ratios were found to be significantly increased (1.9-fold increase in average) in most organs (brain and testes in particular) with Ind-LNC compared to Ind-Sol, regardless of the substrain used. CONCLUSIONS In agreement with previous works, P-gp governs at least in part indinavir uptake into brain and testes. LNC formulation increased indinavir uptake in brain and testes by mechanisms other than, or additional to, P-gp inhibition.
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Affiliation(s)
- Manuela Pereira de Oliveira
- Faculté de Médecine & Pharmacie, EA3809 Pharmacologie des Médicaments Anti-Infectieux, Pôle Biologie-Santé, 40 av. du Recteur Pineau, 86022 Poitiers CEDEX, France
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32
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Kim MK, Han L, Choi MK, Han YH, Kim DD, Chung SJ, Shim CK. Dose dependency in the oral bioavailability of an organic cation model, tributylmethyl ammonium (TBuMA), in rats: Association with the saturation of efflux by the P-gp system on the apical membrane of the intestinal epithelium. J Pharm Sci 2005; 94:2644-55. [PMID: 16258993 DOI: 10.1002/jps.20456] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The oral bioavailability of tributylmethyl ammonium (TBuMA), an organic cation (OC), exhibited a dose-dependency (i.e., 17, 27, and 35% at doses of 0.4, 4, or 12 micromol/kg, respectively) in the rat. Relevant mechanisms were investigated in the present study by estimating the mucosal to serosal (m-s) and serosal to mucosal (s-m) transport of TBuMA across the rat ileum in an Ussing chamber experiment. The m-s permeability rapidly increased with TBuMA concentration in the mucosal side, and then becoming constant at high TBuMA concentrations. Various studies, including temperature- and potential-dependency and inhibition experiments, revealed that carrier-mediated transport mechanisms (most likely OCT1, OCT3, and P-gp) are involved in the s-m transport of TBuMA, and the saturation of the transport at higher concentrations is responsible for the concentration-dependency in the m-s permeability or dose-dependency of the bioavailability of TBuMA. A nonlinear regression of the m-s transport, based on the assumption of a mixed process of linear diffusion and saturable efflux, exhibited a clearance (CLlinear) of 0.343 microL/min/cm2 for the passive diffusion, and an apparent Km of 241 microM for the saturable process. The Km value is consistent with the concentration range in the intestine which is expected to be achieved after the oral dosing of TBuMA at a dose of 0.4 micromol/kg (i.e., 68 approximately 185 microM). Interestingly, the m-s transport of TBuMA was increased by the presence of P-gp substrates or inhibitors in the mucosal side, but not by the mucosal presence of OCT substrates or inhibitors, suggesting that only efflux transport systems on the apical membrane (e.g., P-gp), but not those on the serosal membrane (e.g., OCT1 and OCT3), of the intestinal epithelial cells, are involved in the dose-dependency or concentration dependency. A similar relationship seems likely for drugs that are substrates of efflux transporters on the apical membrane of the intestinal epithelium.
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Affiliation(s)
- Moon Kyoung Kim
- Department of Pharmaceutics, College of Pharmacy, Seoul National University, Shilim-9-dong, Kwanak-Gu, Seoul 151-742, Korea
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Berggren S, Hoogstraate J, Fagerholm U, Lennernäs H. Characterization of jejunal absorption and apical efflux of ropivacaine, lidocaine and bupivacaine in the rat using in situ and in vitro absorption models. Eur J Pharm Sci 2004; 21:553-60. [PMID: 14998587 DOI: 10.1016/j.ejps.2003.12.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2003] [Revised: 12/04/2003] [Accepted: 12/04/2003] [Indexed: 10/26/2022]
Abstract
The purpose of this study was to characterize the rat jejunal passive transport and the possible active efflux of three local anaesthetics, ropivacaine, lidocaine and bupivacaine using two different absorption models, the in situ single-pass intestinal perfusion and the in vitro Ussing chamber model, as well as P-glycoprotein (Pgp)-mediated calcein transport inhibition in Caco-2 cells. Concentration and pH dependence, efflux inhibition by verapamil and digoxin and bi-directional permeability studies were performed to investigate the potential involvement of efflux carriers in the intestinal absorption of the local anaesthetics. In the jejunal perfusion the permeability of these agents appeared to be high, predicting complete intestinal absorption (>90%). There was no effect of the Pgp inhibitors on net absorption for any of the local anaesthetics in the two absorption models. However, in the Ussing chamber at an equal pH of 7.4 at mucosal and serosal sides, the observed jejunal permeability ratios (S-M)/(M-S), of 2.3, 1.8 and 3.0 for ropivacaine, lidocaine and bupivacaine, respectively, indicated at least some involvement of carrier-mediated intestinal secretion. This idea was supported in the calcein AM Pgp transport assay in which two of the tested local anaesthetic agents affected cellular calcein retention. As anticipated for these agents, the mucosal pH conditions were shown to largely affect the gut permeability. The jejunal permeabilities of the local anaesthetics as measured in the two absorption models fitted well in a model comparison that incorporated the permeabilities of six other structurally unrelated drugs. In conclusion, the jejunal permeability of ropivacaine, lidocaine and bupivacaine was high and although evidence was obtained for carrier-mediated intestinal efflux this process appeared not to have a significant influence on the rate and extent of in vivo intestinal absorption. Rather, passive diffusion of these agents seems to be the major mechanism for the intestinal absorption.
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Affiliation(s)
- Sofia Berggren
- Department of Pharmacy, Division of Pharmaceutics, Uppsala University, BMC, P.O. Box 580, Uppsala SE-751 23, Sweden
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Pang KS. MODELING OF INTESTINAL DRUG ABSORPTION: ROLES OF TRANSPORTERS AND METABOLIC ENZYMES (FOR THE GILLETTE REVIEW SERIES). Drug Metab Dispos 2003; 31:1507-19. [PMID: 14625347 DOI: 10.1124/dmd.31.12.1507] [Citation(s) in RCA: 193] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- K Sandy Pang
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
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Tam D, Sun H, Pang KS. Influence of P-glycoprotein, transfer clearances, and drug binding on intestinal metabolism in Caco-2 cell monolayers or membrane preparations: a theoretical analysis. Drug Metab Dispos 2003; 31:1214-26. [PMID: 12975330 DOI: 10.1124/dmd.31.10.1214] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Studies on the Caco-2 cell monolayer system that contained cytochrome P450 and P-glycoprotein activities had advanced the theory that increased intestinal metabolism resulted with increased drug efflux due to an increase in mean residence time (MRT) in the system. To confirm or refute the claim, we developed compartmental models to study the effects of intestinal secretion on the MRT and rates of metabolism under first-order and nonlinear conditions. The theoretical examinations showed that under first-order conditions, intestinal secretion increased the MRT of drug in all compartments but failed to increase the rate of metabolite formation or the total amount of metabolite formed. Instead, reduced metabolic rates arose with increased efflux from cell, either into the apical or the basolateral compartment. By contrast, under saturable metabolic conditions, there were some conditions found whereby rates of metabolism increased with intestinal secretion and rapid reabsorption, albeit the total amount of metabolite formed eventually equaled the administered dose. Intestinal secretion failed to induce higher rates of metabolism for other conditions (saturable cellular binding, cellular efflux, or cell entry). With saturation of metabolic enzymes, drug efflux brought about desaturation, and, upon rapid recovery of drug into the cellular compartment, higher rates of metabolite formation were attained. The simulation study showed that, under first-order conditions, intestinal secretion reduced the rate of metabolism even though the MRT was prolonged within the cell preparation. With nonlinear metabolism, however, instances may exist whereby higher rates of metabolism would result with secretion.
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Affiliation(s)
- Debbie Tam
- Faculty of Pharmacy, University of Toronto, 19 Russell Street, Ontario, Canada M5S 2S2.
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Oselin K, Gerloff T, Mrozikiewicz PM, Pähkla R, Roots I. MDR1 polymorphisms G2677T in exon 21 and C3435T in exon 26 fail to affect rhodamine 123 efflux in peripheral blood lymphocytes. Fundam Clin Pharmacol 2003; 17:463-9. [PMID: 12914549 DOI: 10.1046/j.1472-8206.2003.00163.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
P-glycoprotein (Pgp) is a member of the ABC-transporter family, and in humans, is encoded by the MDR1 gene. Recently, several single-nucleotide polymorphisms in the MDR1 gene were identified. The aim of the present study was to evaluate the effect of the MDR1 genetic polymorphisms G2677T and C3435T on Pgp activity in CD56+ and CD4+ peripheral blood cells. Using flow cytometry, rhodamine 123 (Rh123) efflux was determined in 46 male healthy volunteers. Median Rh123 fluorescence in control sample, after baseline dye uptake, was set as 100%. Rh123 fluorescence in efflux samples, exposed to different efflux periods, was used to calculate the percentage of Rh123 retained in the cells in comparison with control. There was no significant difference in Rh123 efflux in CD56+ cells after 5, 10, 15, and 30 min efflux between individuals with different MDR1 genotypes. Also, in CD4+ cells after 15, 30, 60, and 90 min, Rh123 efflux did not reveal statistically different results for the three genotypes at 2677 and 3435. Rh123 efflux was not enhanced by a 10-day rifampin administration, as determined in 15 individuals before and after rifampin treatment. In conclusion, we found no impact of the MDR1 G2677T and C3435T polymorphisms on Pgp activity in CD56+ and CD4+ peripheral blood lymphocytes.
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Affiliation(s)
- Kersti Oselin
- Institute of Clinical Pharmacology, University Medical Centre Charité, Humboldt University, Schumannstrasse 20/21, D-10117, Berlin, Germany.
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Heimbach T, Oh DM, Li LY, Forsberg M, Savolainen J, Leppänen J, Matsunaga Y, Flynn G, Fleisher D. Absorption rate limit considerations for oral phosphate prodrugs. Pharm Res 2003; 20:848-56. [PMID: 12817887 DOI: 10.1023/a:1023827017224] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE To evaluate the potential of phosphate ester prodrugs to significantly improve the absorptive flux of poorly soluble parent drugs. METHODS Absorptive transport studies of parent drugs and their prodrugs were carried out in Caco-2 cells. Prodrugs of parent drugs with variable aqueous solubilities were tested: Hydrocortisone-phosphate/Hydrocortisone, Fosphenytoin/phenytoin, TAT-59/DP-TAT-59, and Entacapone phosphate/Entacapone. Additional absorption studies were carried out in rats. RESULTS Absorptive fluxes of DP-TAT-59 and phenytoin increased 9.8 or 3.3-fold after dosing TAT-59 and 500 microM fosphenytoin, respectively. Hydrocortisone's flux did not increase with hydrocortisone-phosphate at 100 microM. Permeability of the highly lipophilic and protein bound compound, DP-TAT-59, was significantly increased with serosal albumin. No permeability increase was observed for the other drugs with albumin. Entacapone phosphate failed to improve the flux of entacapone compared to an entacapone solution, but the prodrug solution did yield higher entacapone plasma levels in rats when compared with an entacapone suspension. CONCLUSION Ideal phosphate prodrug candidates are characterized by high permeability and low solubility (BCS Class II drugs). For low dose BCS Class II drug candidates, however, no biopharmaceutical advantage may be gained. Phosphate prodrugs of parent drugs with limited permeability may fail. When screening highly lipophilic parent drugs transport studies should be done with albumin.
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Affiliation(s)
- Tycho Heimbach
- The University of Michigan, College of Pharmacy, 428 Church Street, Ann Arbor, Michigan 48109, USA
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Tolle-Sander S, Rautio J, Wring S, Polli JW, Polli JE. Midazolam exhibits characteristics of a highly permeable P-glycoprotein substrate. Pharm Res 2003; 20:757-64. [PMID: 12751631 DOI: 10.1023/a:1023433502647] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The purpose of this study was to investigate whether midazolam exhibits characteristics of a highly permeable P-glycoprotein (P-gp) substrate and to evaluate the potential influence of P-gp inhibition on 1-OH midazolam formation during midazolam transport. METHODS P-gp interaction was investigated by P-gp ATPase assay, efflux inhibition studies, and transport studies of midazolam across MDR1-MDCK and 1-alpha,25-dihydroxy vitamin D3-induced Caco-2 monolayers with and without the P-gp inhibitor GF120918. RESULTS Midazolam was highly permeable and transport appeared essentially unpolarized. In MDR1-MDCK, the basolateral-to-apical (B-to-A) permeability was slightly higher (16%) than apical-to-basolateral (A-to-B) permeability (p = 0.04); GF120918 increased A-to-B permeability by 27% (p = 0.01), and increased cellular midazolam accumulation during A-to-B transport by 45% (p = 0.01). Midazolam (200 microM) decreased rhodamine123 and vinblastine B/A ratios 3-fold (p < 0.006), while increasing their cellular accumulation (p < 0.003). P-gp ATPase activation by midazolam was dose-dependent and saturable [Km = 11.5(+/- 4.0) microM; Vmax = 41.1(+/- 7.4) nmol/mg/min]. P-gp inhibition increased 1-OH midazolam formation in A-to-B studies 1.3-fold when midazolam donor > or = 10 microM (p < 0.03). In B-to-A studies, P-gp inhibition did not significantly increase metabolite formation (p = 0.06). Midazolam's extraction ratio was not influenced by P-gp (p = 0.2). CONCLUSION The results indicate that midazolam exhibited characteristics of a highly permeable P-gp substrate. 1-OH midazolam formation during A-to-B midazolam transport increased slightly when P-gp was inhibited.
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Affiliation(s)
- Sanna Tolle-Sander
- Department of Pharmaceutical Sciences, University of Maryland, 20 N Pine Street, Baltimore, Maryland, USA
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Engman H, Tannergren C, Artursson P, Lennernäs H. Enantioselective transport and CYP3A4-mediated metabolism of R/S-verapamil in Caco-2 cell monolayers. Eur J Pharm Sci 2003; 19:57-65. [PMID: 12729862 DOI: 10.1016/s0928-0987(03)00065-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have evaluated the passive and carrier-mediated intestinal transport and CYP3A4-mediated metabolism of R/S-verapamil with respect to dose dependency and enantioselectivity in modified Caco-2 cells. The present in vitro results were compared to published data from human in vivo and rat in situ jejunal perfusions with R/S-verapamil. Caco-2 cell permeability to enantiomers of verapamil and norverapamil was weakly concentration dependent (2.5-100 microM). While Caco-2 permeability to verapamil was 2.6- to 3.7-fold lower than in the human jejunum, it was 1.4- to 2.3-fold higher than in rats. However, all three models classified R- and S-verapamil as high permeability compounds according to the biopharmaceutical classification system. In accordance with human and rat data, R/S-verapamil was transported to a minor extent by carrier-mediated mechanisms in Caco-2 cells. Neither the passive nor the carrier-mediated permeability was enantioselective in any of the three models. CYP3A4-mediated demethylation to R/S-norverapamil was enantioselective in Caco-2 cells. Apparent V(max) and K(m) values for the conversion of R-verapamil were 3.2 pmol/min/insert and 0.7 microM, respectively, and for S-verapamil, 5.4 pmol/min/insert and 0.6 microM, respectively. The enantioselectivity in the CYP3A4-metabolism observed in Caco-2 cells was in agreement with human data, but not with rat data, indicating that Caco-2 cells better reflect the human small intestine in this regard. However, all three models suggested that intestinal permeability to verapamil is unaffected by CYP3A4-activity. In summary, modified Caco-2 cells and human jejunum were qualitatively related with respect to R-and S-verapamil transport and CYP3A4-metabolism.
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Affiliation(s)
- Helena Engman
- Department of Pharmacy, Uppsala University, Box 580, SE-751 23 Uppsala, Sweden
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Cummins CL, Salphati L, Reid MJ, Benet LZ. In vivo modulation of intestinal CYP3A metabolism by P-glycoprotein: studies using the rat single-pass intestinal perfusion model. J Pharmacol Exp Ther 2003; 305:306-14. [PMID: 12649383 DOI: 10.1124/jpet.102.044719] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
P-Glycoprotein (P-gp) has been hypothesized to modulate intestinal drug metabolism by increasing the exposure of drug to intracellular CYP3A through repeated cycles of drug absorption and efflux. The rat single-pass intestinal perfusion model was used to study this interplay in vivo. N-Methyl piperazine-Phe-homoPhe-vinylsulfone phenyl (K77), a peptidomimetic cysteine protease inhibitor (CYP3A/P-gp substrate), and midazolam (CYP3A substrate) were each perfused through a segment of rat ileum alone and with the P-gp inhibitor N-(4-[2-(1,2,3,4-tetrahydro-6,7-dimethoxy-2-isoquinolinyl)-ethyl]-phenyl)-9,10-dihydro-5-methoxy-9-oxo-4-acridine carboxamine (GG918). Samples were obtained continuously from the outlet perfusate and the mesenteric vein at 5-min intervals for 40 to 60 min. The parent drug and two main metabolites of K77 (N-desmethyl and N-oxide) and midazolam (1-OH and 4-OH) were quantitated by liquid chromatography/mass spectrometry. K77 appearance in the mesenteric blood (P(blood) = 5 +/- 3 x 10(-6) cm/s) was increased 3-fold with GG918, whereas midazolam permeability (P(blood) = 1.1 +/- 0.3 x 10(-4) cm/s) was unchanged by GG918. K77 metabolites were preferentially excreted into the lumen, 4-OH midazolam was found equally in lumen and blood, and 1-OH was mainly excreted into blood. The extent of metabolism was estimated by calculating the fraction metabolized = 1 - P(blood)/P(lumen) and the extraction ratio (ER) determined from the direct measurement of known metabolites as ER = sum metabolites(all)/(sum metabolites(all) + drug in blood). When P-gp was inhibited, the fraction metabolized for K77 was decreased (95 to 85%) and the ER tended toward a decrease, whereas no differences in either parameter were observed for midazolam (not a P-gp substrate). These data support a role for P-gp in modulating the extent of intestinal metabolism in vivo by controlling drug access to the enzyme.
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Affiliation(s)
- Carolyn L Cummins
- Department of Biopharmaceutical Sciences, University of California, San Francisco, California 94143-0446, USA.
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Tam D, Tirona RG, Pang KS. Segmental intestinal transporters and metabolic enzymes on intestinal drug absorption. Drug Metab Dispos 2003; 31:373-83. [PMID: 12642462 DOI: 10.1124/dmd.31.4.373] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recently, a physiologically-based, segregated flow model that incorporates separate intestinal tissue and flow to both a nonabsorptive and an absorptive outermost layer (enterocytes) was shown to better describe the observations on route-dependent morphine glucuronidation in the rat small intestine than a traditional physiologically-based model. These theoretical models were expanded, as the segmental segregated flow model and the segmental traditional model, to view the intestine as three segments of equal lengths receiving equal flows to accommodate heterogeneities in segmental transporter and metabolic functions. The influence of heterogeneity in absorptive, exsorptive, and metabolic functions on drug clearance, bioavailability (F), and metabolite formation after intravenous and oral dosing was examined for the intestine when the tissue was the only organ of removal. Simulations were performed for first-order conditions, when drug partitioned readily (flow-limited distribution) or less readily (membrane-limited distribution) into intestinal tissue, and for different gastrointestinal transit times. The intestinal clearance was found to be inversely related to the rate constant for absorption of a drug that was subjected to secretion and was positively correlated with the metabolic and secretory intrinsic clearances. F was positively correlated with the absorption rate constant but was inversely related to the metabolic and secretory intrinsic clearances. The gastrointestinal transit time decreased metabolite formation, increased clearance, and decreased F. The simulations further showed that a descending metabolic intrinsic clearance yielded a lower F and an ascending segmental distribution of metabolic intrinsic clearance yielded a higher F.
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Affiliation(s)
- Debbie Tam
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, 19 Russell Street, Toronto, Ontario, Canada M5S 2S2
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Burton PS, Goodwin JT, Vidmar TJ, Amore BM. Predicting drug absorption: how nature made it a difficult problem. J Pharmacol Exp Ther 2002; 303:889-95. [PMID: 12438506 DOI: 10.1124/jpet.102.035006] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Significant recent work has focused on predicting drug absorption from structure. Several misperceptions regarding the nature of absorption seem to be common. Among these is that intestinal absorption, permeability, fraction absorbed, and, in some cases, even bioavailability, are equivalent properties and can be used interchangeably. A second common misperception is that absorption, permeability, etc. are discrete, fundamental properties of the molecule and can be predicted solely from some structural representation of the drug. In reality, drug absorption is a complex process dependent upon drug properties such as solubility and permeability, formulation factors, and physiological variables, including regional permeability differences, pH, lumenal and mucosal enzymology, and intestinal motility, among others. This article will explore the influence of these different variables on drug absorption and the implications with regards to attempting to develop predictive drug absorption algorithms.
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Affiliation(s)
- Philip S Burton
- Drug Absorption and Transport, Pharmacia, Kalamazoo, Michigan 49007, USA.
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