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Roger E, Lagarce F, Benoit JP. The gastrointestinal stability of lipid nanocapsules. Int J Pharm 2009; 379:260-5. [PMID: 19524655 DOI: 10.1016/j.ijpharm.2009.05.069] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2009] [Revised: 03/27/2009] [Accepted: 05/18/2009] [Indexed: 11/26/2022]
Abstract
The in vitro gastrointestinal stability of lipid nanocapsules (LNCs) was studied in different media. The size of LNCs was determined in simulated gastric and intestinal media. In updated fasted state simulated intestinal fluid (FaSSIF-V2) and updated fed state simulated intestinal fluid (FeSSIF-V2) media, the encapsulation ratio of paclitaxel-loaded LNCs was also measured. The size of LNCs was not modified after 3h in simulated gastric fluid and simulated intestinal fluid described by the United States Pharmacopeia, in FaSSIF, FaSSIF-V2, and in FeSSIF. Moreover, in the presence of pancreatin in FeSSIF-V2, a decreased above 30% of the loading of paclitaxel was observed. This was attributed to the presence of lipase in pancreatin that could interact with Lipoid (a mixture of phosphatidylcholine and phosphatidylethanolamine), present on the shell of LNC. As a conclusion, LNCs were stable on gastric medium and fasted state intestinal medium.
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Affiliation(s)
- E Roger
- Ethypharm, 194 bureau de la Colline-bâtiment D, 92213-Saint-Cloud Cedex, France
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Oostendorp RL, Huitema A, Rosing H, Jansen RS, Ter Heine R, Keessen M, Beijnen JH, Schellens JHM. Coadministration of ritonavir strongly enhances the apparent oral bioavailability of docetaxel in patients with solid tumors. Clin Cancer Res 2009; 15:4228-33. [PMID: 19509162 DOI: 10.1158/1078-0432.ccr-08-2944] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To enhance the systemic exposure to oral docetaxel by coadministration of ritonavir, an efficacious inhibitor of CYP 3A4 with minor P-glycoprotein inhibiting effects, in patients with cancer. EXPERIMENTAL DESIGN A proof-of-concept study was carried out in 12 patients with solid tumors. The first cohort of patients (n = 4) received 10 mg and the subsequent cohort (n = 8) 100 mg of oral docetaxel, coadministered with 100 mg oral ritonavir randomized simultaneously or ritonavir given 60 minutes before docetaxel on days 1 and 8. On day 15 or 22, patients received 100 mg i.v. docetaxel. RESULTS The area under the plasma concentration-time curve in patients who received 10 mg oral docetaxel in combination with ritonavir was low, and the dose could safely be increased to 100 mg. The area under the plasma concentration-time curve in patients who received 100 mg oral docetaxel combined with ritonavir simultaneously or ritonavir given 60 minutes before docetaxel was 2.4 +/- 1.5 and 2.8 +/- 1.4 mg/h/L, respectively, compared with 1.9 +/- 0.4 mg/h/L after i.v. docetaxel. The apparent oral bioavailability of docetaxel combined with ritonavir simultaneously or ritonavir given 60 minutes before docetaxel was 131% +/- 90% and 161% +/- 91%, respectively. The oral combination of docetaxel and ritonavir was well tolerated. CONCLUSION Coadministration of ritonavir significantly enhanced the apparent oral bioavailability of docetaxel. These data are promising and form the basis for further development of a clinically applicable oral formulation of docetaxel combined with ritonavir.
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Affiliation(s)
- Roos L Oostendorp
- Department of Medical Oncology, Division of Clinical Pharmacology, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands.
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Mohs AM, Duan H, Kairdolf BA, Smith AM, Nie S. Proton-Resistant Quantum Dots: Stability in Gastrointestinal Fluids and Implications for Oral Delivery of Nanoparticle Agents. NANO RESEARCH 2009; 2:500-508. [PMID: 20379372 PMCID: PMC2850447 DOI: 10.1007/s12274-009-9046-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2009] [Revised: 03/30/2009] [Accepted: 04/01/2009] [Indexed: 05/29/2023]
Abstract
Semiconductor quantum dots (QDs) have shown great promise as fluorescent probes for molecular, cellular and in-vivo imaging. However, the fluorescence of traditional polymer-encapsulated QDs is often quenched by proton-induced etching in acidic environments. This is a major problem for QD applications in the gastrointestinal tract because the gastric (stomach) environment is strongly acidic (pH 1-2). Here we report the use of proton-resistant surface coatings to stabilize QD fluorescence under acidic conditions. Using both hyperbranched polyethylenimine (PEI) and its polyethylene glycol derivative (PEG grafted PEI), we show that the fluorescence of core-shell CdSe/CdS/ZnS QDs is effectively protected from quenching in simulated gastric fluids. In comparison, amphiphilic lipid or polymer coatings provide no protection under similarly acidic conditions. The proton-resistant QDs are found to cause moderate membrane damage to cultured epithelial cells, but PEGylation (PEG grafting) can be used to reduce cellular toxicity and to improved nanoparticle stability.
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Affiliation(s)
- Aaron M Mohs
- Departments of Biomedical Engineering and Chemistry, Emory University and Georgia Institute of Technology, 101 Woodruff Circle NE, Suite 2001, Atlanta, Georgia 30322, USA
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Lyu SY, Park WB. Mistletoe lectin modulates intestinal epithelial cell-derived cytokines and B cell IgA secretion. Arch Pharm Res 2009; 32:443-51. [DOI: 10.1007/s12272-009-1319-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 01/19/2009] [Accepted: 02/26/2009] [Indexed: 12/15/2022]
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Branco MC, Schneider JP. Self-assembling materials for therapeutic delivery. Acta Biomater 2009; 5:817-31. [PMID: 19010748 PMCID: PMC2729065 DOI: 10.1016/j.actbio.2008.09.018] [Citation(s) in RCA: 324] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 09/06/2008] [Accepted: 09/23/2008] [Indexed: 01/18/2023]
Abstract
A growing number of medications must be administered through parenteral delivery, i.e., intravenous, intramuscular, or subcutaneous injection, to ensure effectiveness of the therapeutic. For some therapeutics, the use of delivery vehicles in conjunction with this delivery mechanism can improve drug efficacy and patient compliance. Macromolecular self-assembly has been exploited recently to engineer materials for the encapsulation and controlled delivery of therapeutics. Self-assembled materials offer the advantages of conventional crosslinked materials normally used for release, but also provide the ability to tailor specific bulk material properties, such as release profiles, at the molecular level via monomer design. As a result, the design of materials from the "bottom up" approach has generated a variety of supramolecular devices for biomedical applications. This review provides an overview of self-assembling molecules, their resultant structures, and their use in therapeutic delivery. It highlights the current progress in the design of polymer- and peptide-based self-assembled materials.
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Affiliation(s)
- Monica C. Branco
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
- Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA
| | - Joel P. Schneider
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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Stanley LA, Horsburgh BC, Ross J, Scheer N, Wolf CR. Drug transporters: Gatekeepers controlling access of xenobiotics to the cellular interior. Drug Metab Rev 2009; 41:27-65. [DOI: 10.1080/03602530802605040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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57
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Abstract
This chapter provides a review of the pharmacogenetics of membrane transporters, including adenosine triphosphate-binding cassette (ABC) transporters and organic anion transporting proteins (OATPs). Membrane transporters are heavily involved in drug disposition by actively transporting substrate drugs between organs and tissues. As such, polymorphisms in the genes encoding these proteins may have a significant effect on the absorption, distribution, metabolism, and excretion of compounds. The techniques used to identify substrates and inhibitors of these proteins and subsequently assess the effect of genetic mutation on transport, both in vitro and in vivo, are outlined and discussed. Finally, studies linking transporter genotype with clinical outcomes are discussed.
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Abstract
Oral administration of anticancer agents is preferred by patients for its convenience and potential for use in outpatient and palliative setting. In addition, oral administration facilitates a prolonged exposure to the cytotoxic agents. Enhancement of bioavailability of emerging cytotoxic agents is a pre-requisite for successful development of oral modes of cancer treatment. Over the last decade, our studies have focused specifically on the utilization of large (MW>10(5)) and non-degradable polymers in oral chemotherapy. A family of block-graft copolymers of the poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) Pluronic(R) polyethers and poly(acrylic acid) (PAA) bound by carbon-carbon bonds emerged, wherein both polymeric components are generally recognized as safe. Animal studies with Pluronic-PAA copolymers demonstrated that these molecules are excreted when administered orally and do not absorb into the systemic circulation. The Pluronic-PAA copolymers are surface-active and self-assemble, at physiological pH, into intra- and intermolecular micelles with hydrophobic cores of dehydrated PPO and multilayered coronas of hydrophilic PEO and partially ionized PAA segments. These micelles efficiently solubilize hydrophobic drugs such as paclitaxel and steroids and protect molecules such as camptothecins from the hydrolytic reactions. High surface activity of the Pluronic-PAA copolymers in water results in interactions with cell membranes and suppression of the membrane pumps such as P-glycoprotein. The ionizable carboxyls in the micellar corona facilitate mucoadhesion that enhances the residence time of the micelles and solubilized drugs in the gastrointestinal tract. Large payloads of the Pluronic-PAA micelles with weakly basic and water-soluble drugs such as doxorubicin and its analogs, mitomycin C, mitoxantrone, fluorouracil, and cyclophosphamide are achieved through electrostatic interactions with the micellar corona. Mechanical and physical properties of the Pluronic-PAA powders, blends, and micelles allow for formulation procedures where an active is simply dispersed into an aqueous Pluronic-PAA micellar formulation followed by optional lyophilization and processing into a ready dosage form. We review a number of in vivo and in vitro experiments demonstrating that that the oral administration of the cytotoxics formulated with the Pluronic-PAA copolymer micelles results in enhanced drug bioavailability.
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Abstract
Human jejunal permeability (P(eff)) is determined in the intestinal region with the highest expression of carrier proteins and largest surface area. Intestinal P(eff) are often based on multiple parallel transport processes. Site-specific jejunal P(eff) cannot reflect the permeability along the intestinal tract, but they are useful for approximating the fraction oral dose absorbed. It seems like drugs with a jejunal P(eff) > 1.5 x 10(-4) cm s(-1) will be completely absorbed no matter which transport mechanism(s) are utilized. Many drugs that are significantly effluxed in vitro have a rapid and complete intestinal absorption (i.e. >85%) mediated by passive transcellular diffusion. The determined jejunal P(eff) for drugs transported mainly by absorptive carriers (such as peptide and amino acid transporters) will accurately predict the fraction of the dose absorbed as a consequence of the regional expression. The data also show that: (1) the human intestinal epithelium has a large resistance towards large and hydrophilic compounds; and (2) the paracellular route has a low contribution for compounds larger than approximately molecular weight 200. There is a need for more exploratory in vivo studies to clarify drug absorption and first-pass extraction along the intestine. One is encouraged to develop in vivo perfusion techniques for more distal parts of the gastrointestinal tract in humans. This would stimulate the development of more relevant and complex in vitro absorption models and form the basis for an accurate physiologically based pharmacokinetic modelling of oral drug absorption.
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Affiliation(s)
- H Lennernäs
- Biopharmaceutics, Uppsala University, Uppsala, Sweden.
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60
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Bansal T, Singh M, Mishra G, Talegaonkar S, Khar RK, Jaggi M, Mukherjee R. Concurrent determination of topotecan and model permeability markers (atenolol, antipyrine, propranolol and furosemide) by reversed phase liquid chromatography: Utility in Caco-2 intestinal absorption studies. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 859:261-6. [PMID: 17936093 DOI: 10.1016/j.jchromb.2007.09.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2007] [Revised: 09/10/2007] [Accepted: 09/19/2007] [Indexed: 10/22/2022]
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Abstract
Multidrug resistance is a major obstacle to successful cancer treatment. One mechanism by which cells can become resistant to chemotherapy is the expression of ABC transporters that use the energy of ATP hydrolysis to transport a wide variety of substrates across the cell membrane. There are three human ABC transporters primarily associated with the multidrug resistance phenomenon, namely Pgp, MRP1, and ABCG2. All three have broad and, to a certain extent, overlapping substrate specificities, transporting the major drugs currently used in cancer chemotherapy. ABCG2 is the most recently described of the three major multidrug-resistance pumps, and its substrates include mitoxantrone, topotecan, irinotecan, flavopiridol, and methotrexate. Despite several studies reporting ABCG2 expression in normal and malignant tissues, no trials have thus far addressed the role of ABCG2 in clinical drug resistance. This gives us an opportunity to critically review the disappointing results of past clinical trials targeting Pgp and to propose strategies for ABCG2. We need to know in which tumor types ABCG2 contributes to the resistance phenotype. We also need to develop standardized assays to detect ABCG2 expression in vivo and to carefully select the chemotherapeutic agents and clinical trial designs. This review focuses on our current knowledge about normal tissue distribution, tumor expression profiles, and substrates and inhibitors of ABCG2, together with lessons learned from clinical trials with Pgp inhibitors. Implications of SNPs in the ABCG2 gene affecting the pharmacokinetics of substrate drugs, including many non-chemotherapy agents and ABCG2 expression in the SP population of stem cells are also discussed.
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Affiliation(s)
- Robert W Robey
- Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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62
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Martignoni M, Groothuis GMM, de Kanter R. Species differences between mouse, rat, dog, monkey and human CYP-mediated drug metabolism, inhibition and induction. Expert Opin Drug Metab Toxicol 2007; 2:875-94. [PMID: 17125407 DOI: 10.1517/17425255.2.6.875] [Citation(s) in RCA: 987] [Impact Index Per Article: 58.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Animal models are commonly used in the preclinical development of new drugs to predict the metabolic behaviour of new compounds in humans. It is, however, important to realise that humans differ from animals with regards to isoform composition, expression and catalytic activities of drug-metabolising enzymes. In this review the authors describe similarities and differences in this respect among the different species, including man. This may be helpful for drug researchers to choose the most relevant animal species in which the metabolism of a compound can be studied for extrapolating the results to humans. The authors focus on CYPs, which are the main enzymes involved in numerous oxidative reactions and often play a critical role in the metabolism and pharmacokinetics of xenobiotics. In addition, induction and inhibition of CYPs are compared among species. The authors conclude that CYP2E1 shows no large differences between species, and extrapolation between species appears to hold quite well. In contrast, the species-specific isoforms of CYP1A, -2C, -2D and -3A show appreciable interspecies differences in terms of catalytic activity and some caution should be applied when extrapolating metabolism data from animal models to humans.
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Affiliation(s)
- Marcella Martignoni
- Nerviano Medical Sciences, Preclinical Development, Viale Pasteur 10, Nerviano (MI), Italy.
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63
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Constantinides PP, Wasan KM. Lipid Formulation Strategies for Enhancing Intestinal Transport and Absorption of P-Glycoprotein (P-gp) Substrate Drugs: In vitro/In vivo Case Studies. J Pharm Sci 2007; 96:235-48. [PMID: 17051593 DOI: 10.1002/jps.20780] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The intestinal efflux pump, P-glycoprotein (P-gp), located in the apical membranes of intestinal absorptive cells, can reduce the bioavailability of a wide range of drugs which are substrates for this membrane transporter. In addition to anticancer and anti-HIV drugs, NCEs for other disease indications are P-gp substrates and there is considerable interest in inhibiting P-gp and thus increasing the bioavailability of these molecules. In this review article, an overview of P-gp and its role in drug transport and absorption will be presented first and then formulation strategies to effectively inhibit P-gp will be discussed and compared. These strategies independently and in combination, are: (a) coadministration of another P-gp substrate/specific inhibitor, and (b) incorporation of a nonspecific lipid and/or polymer excipient in the formulation. The first approach, although very effective in inhibiting P-gp, utilizes a second active compound in the formulation and thus imposes regulatory constraints and long development timelines on such combination products. Excipient inhibitors appear to have minimal nonspecific pharmacological activity and thus potential side effects of specific active compound inhibitors can be avoided. Case studies will be presented where specific active compounds, surfactants, polymers, and formulations incorporating these molecules are shown to significantly improve the intestinal absorption of poorly soluble and absorbed drugs as a result of P-gp inhibition and enhanced drug transport in vitro.
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Liou JP, Mahindroo N, Chang CW, Guo FM, Lee SWH, Tan UK, Yeh TK, Kuo CC, Chang YW, Lu PH, Tung YS, Lin KT, Chang JY, Hsieh HP. Structure-activity relationship studies of 3-aroylindoles as potent antimitotic agents. ChemMedChem 2007; 1:1106-18. [PMID: 16952120 DOI: 10.1002/cmdc.200600125] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The concise synthesis and structure-activity relationship (SAR) studies of 3-aroylindoles were carried out in an effort to improve the potency and solubility of anticancer drug candidate BPR0L075 (8) by exploring structure modifications through three regimens: substitution of the B ring, at the N1 position, and of the 3-carbonyl linker. The SAR information revealed that the methoxy group of the B ring could be replaced with an electron-donating group such as methyl (in compound 9) or N,N-dimethylamino (in compound 13) while retaining both strong cytotoxic and antitubulin activities. The introduction of amide (compounds 30-33) and carbamate (compounds 34-37) functionalities at the N1 position of 8 gave analogues with potent antiproliferative activities. The cytotoxic potency of 8 was improved by replacing the carbonyl group with sulfide (compound 41) or oxygen (compound 43), indicating that the carbonyl moiety is important but not essential. The N,N-dimethylamino derivative 13 not only displayed potent cytotoxicity and antitubulin activity, but also showed a markedly improved physicochemical profile relative to the parent compound.
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Affiliation(s)
- Jing-Ping Liou
- Division of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, Miaoli County 350, Taiwan, Republic of China
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Labrie P, Maddaford SP, Lacroix J, Catalano C, Lee DKH, Rakhit S, Gaudreault RC. In vitro activity of novel dual action MDR anthranilamide modulators with inhibitory activity at CYP-450. Bioorg Med Chem 2006; 14:7972-87. [PMID: 16904325 DOI: 10.1016/j.bmc.2006.07.055] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 07/11/2006] [Accepted: 07/26/2006] [Indexed: 10/24/2022]
Abstract
Synthesis and in vitro cytotoxicity assays of new anthranilamide MDR modulators have been performed to assess their inhibition potency of the P-glycoprotein (P-gp) transporter. The aromatic spacer group between nitrogen atoms (N1 and N2) in the known inhibitor XR9576 was replaced with a flexible alkyl chain of 2 to 6 carbon atoms in length. 6,7-Dimethoxy-1,2,3,4-tetrahydroisoquinoline and their open-chain N-methylhomoveratrylamine counterparts were shown to be potent P-gp inhibitors. The maximal inhibition was obtained when using an ethyl or propyl spacer. Several compounds were more potent than verapamil and intrinsically less cytotoxic than XR9576. In addition, in vitro metabolism studies of 23a with a subset of human CYP-450 isoforms revealed that, unlike XR9576, 23a inhibited CYP3A4, an enzyme that colocalizes with P-gp in the intestine and contributes to tumor cell chemoresistance by enhancing the biodisposition of anticancer drugs such as paclitaxel toward metabolism. In this context, 22a might be a suitable candidate for further drug development.
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Affiliation(s)
- Philippe Labrie
- Instituts de Biomateriaux et des Biotechnologies, Hopital St-François d'Assise, Laval University, Que., Canada G1L 3L5.
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Lagas JS, Vlaming ML, van Tellingen O, Wagenaar E, Jansen RS, Rosing H, Beijnen JH, Schinkel AH. Multidrug resistance protein 2 is an important determinant of paclitaxel pharmacokinetics. Clin Cancer Res 2006; 12:6125-32. [PMID: 17062689 DOI: 10.1158/1078-0432.ccr-06-1352] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE P-glycoprotein (P-gp; ABCB1) efficiently transports lipophilic amphipathic drugs, including the widely used anticancer drug paclitaxel (Taxol). We found previously that human multidrug resistance protein 2 (MRP2; ABCC2) also transports paclitaxel in vitro, and although we expected that paclitaxel pharmacokinetics would be dominated by P-gp, the effect of Mrp2 was tested in vivo. EXPERIMENTAL DESIGN We generated and characterized Mdr1a/1b/Mrp2(-/-) mice, allowing assessment of the distinct roles of Mrp2 and Mdr1a/1b P-gp in paclitaxel pharmacokinetics. RESULTS Surprisingly, the effect of Mrp2 on i.v. administration of paclitaxel was as great as that of P-gp. The area under plasma concentration-time curve (AUC)i.v. in both Mrp2(-/-) and Mdr1a/1b(-/-) mice was 1.3-fold higher than in wild-type mice, and in Mdr1a/1b/Mrp2(-/-) mice, a 1.7-fold increase was found. In spite of this similar effect, Mrp2 and P-gp had mostly complementary functions in paclitaxel elimination. Mrp2 dominated the hepatobiliary excretion, which was reduced by 80% in Mrp2(-/-) mice. In contrast, P-gp dominated the direct intestinal excretion, with a minor role for Mrp2. The AUCoral of paclitaxel was 8.5-fold increased by Mdr1a/1b deficiency but not affected by Mrp2 deficiency. However, in the absence of Mdr1a/1b P-gp, additional Mrp2 deficiency increased the AUCoral another 1.7-fold. CONCLUSIONS Thus far, Mrp2 was thought to mainly affect organic anionic drugs in vivo. Our data show that Mrp2 can also be a major determinant of the pharmacokinetic behavior of highly lipophilic anticancer drugs, even in the presence of other efficient transporters. Variation in MRP2 activity might thus directly affect the effective exposure to paclitaxel, on i.v. administration, but also on oral administration, especially when P-gp activity is inhibited.
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Affiliation(s)
- Jurjen S Lagas
- Division of Experimental Therapy, The Netherlands Cancer Institute, Amsterdam, the Netherlands
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McEntee MC, Rassnick KM, Lewis LD, Zgola MM, Beaulieu BB, Balkman CE, Page RL. Phase I and pharmacokinetic evaluation of the combination of orally administered docetaxel and cyclosporin A in tumor-bearing dogs. Am J Vet Res 2006; 67:1057-62. [PMID: 16740102 DOI: 10.2460/ajvr.67.6.1057] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the maximum tolerated dose and characterize the pharmacokinetic disposition of an orally administered combination of docetaxel and cyclosporin A (CSA) in dogs with tumors. ANIMALS 16 client-owned dogs with metastatic or advanced-stage refractory tumors. PROCEDURES An open-label, dose-escalation, single-dose, phase I study of docetaxel administered in combination with a fixed dose of CSA was conducted. Docetaxel (at doses of 1.5, 1.625, or 1.75 mg/kg) and CSA (5 mg/kg) were administered concurrently via gavage twice during a 3-week period. Plasma docetaxel concentrations were quantified by use of high-performance liquid chromatography, and pharmacokinetic disposition was characterized by use of noncompartmental analysis. Dogs' clinical signs and results of hematologic and biochemical analyses were monitored for evidence of toxicosis. RESULTS No acute hypersensitivity reactions were observed after oral administration of docetaxel. Disposition of docetaxel was dose independent over the range evaluated, and pharmacokinetic variables were similar to those reported in previous studies involving healthy dogs, with the exception that values for clearance were significantly higher in the dogs reported here. The maximum tolerated dose of docetaxel was 1.625 mg/kg. Gastrointestinal signs of toxicosis were dose limiting. CONCLUSIONS AND CLINICAL RELEVANCE The absence of myelosuppression suggested that the docetaxel-CSA combination may be administered more frequently than the schedule used. Further studies are warranted to evaluate combination treatment administered on a biweekly schedule in dogs with epithelial tumors.
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Affiliation(s)
- Margaret C McEntee
- Section of Oncology, Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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Constantinides PP, Han J, Davis SS. Advances in the use of tocols as drug delivery vehicles. Pharm Res 2006; 23:243-55. [PMID: 16421666 DOI: 10.1007/s11095-005-9262-9] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Accepted: 10/25/2005] [Indexed: 12/12/2022]
Abstract
There has been increasing interest in recent years in the drug delivery applications of tocols and their derivatives. Their biocompatibility and potential to deliver both poorly soluble and water-soluble drugs make tocols attractive as drug delivery vehicles. This review article will focus primarily on topical, oral, and parenteral drug administration using tocols, although other routes of delivery such as pulmonary and nasal will also be discussed. After an overview of the tocol structures, physicochemical properties with emphasis on their solvent properties, functions, and metabolism, specific case studies will be discussed where tocols have been successfully used in topical, oral, and parenteral drug formulations and marketed drug products. Case studies will be extended to those where tocol-based formulations were administered pulmonarily and nasally. As more clinical data and marketed drug products emerge, the utility and therapeutic value of tocols will certainly increase.
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Abstract
Multidrug resistance (MDR) results in the loss of activity of anticancer agents against cells possessing the MDR phenotype. In some cases, tumor cells are intrinsically resistant to chemotherapeutic drugs (intrinsic resistance), while in other instances cells become resistant after exposure to cytotoxic agents (acquired resistance). MDR has a significant impact on the management of patients with solid tumors, including those with breast cancer, where it has been previously correlated with a decreased response to treatment and a poor prognosis. Taxanes are among the most important components of chemotherapy regimens to treat recurrent breast cancer. In taxane-refractory cells, the two mechanisms most commonly associated with the development of MDR are the overexpression of members of the ATP-binding cassette family of transporters, of which P-glycoprotein is the best known, and alterations of tubulin, which is the cellular target of the taxanes. In vitro and in vivo models have been developed to study the development of MDR and to assess the potential clinical application of MDR modulators. However, despite promising advances using MDR modulators in preclinical models, clinical applications have met with limited success. Novel strategies are needed to circumvent the development of drug resistance. New cytotoxic agents capable of evading MDR offer hope for patients with breast cancer.
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Affiliation(s)
- Antonio Tito Fojo
- Cancer Therapeutics Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
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Josserand V, Pélerin H, de Bruin B, Jego B, Kuhnast B, Hinnen F, Ducongé F, Boisgard R, Beuvon F, Chassoux F, Daumas-Duport C, Ezan E, Dollé F, Mabondzo A, Tavitian B. Evaluation of Drug Penetration into the Brain: A Double Study by in Vivo Imaging with Positron Emission Tomography and Using an in Vitro Model of the Human Blood-Brain Barrier. J Pharmacol Exp Ther 2005; 316:79-86. [PMID: 16210395 DOI: 10.1124/jpet.105.089102] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The blood-brain barrier (BBB) permeabilities of 11 compounds were measured both in vitro with a newly developed coculture-based model of human BBB and in vivo with positron emission tomography (PET). The 11 compounds were fluoropyridinyl derivatives labeled with the positron-emitter fluorine-18, [(18)F]F-A-85380 [2-[(18)F]fluoro-3-[2(S)-2 azetidinylmethoxy]pyridine], and 10 selected N-substituted-azetidinyl and pyrrolidinyl closely related [(18)F]fluoropyridinyl derivatives (including [N'-aromatic/aliphatic]-thioureas, -ureas, and -amides). The in vitro BBB model, a new coculture system of primary human brain endothelial cells and astrocytes, was used to measure the permeability coefficient for each compound. Dynamic PET studies were performed in rats with the same compounds, and a two-compartment model analysis was used to calculate their in vivo permeability coefficients. The 11 derivatives differed in their degree of BBB passage and transport mechanism. The analysis of PET data showed a significant cerebral uptake for six derivatives, for which the in vitro evaluation indicated active influx or free diffusion. Five derivatives displayed low in vivo cerebral uptake, in agreement with the observation of an in vitro active efflux. Overall, there was a remarkable correlation between the in vitro and in vivo permeability coefficients (r = 0.99). This double study proves a close correlationship between the assessment of the BBB passage in vitro and in vivo. The in vitro model of human BBB offers the possibility of subtle discrimination of various BBB permeability degrees and transport mechanisms. Conversely, small animal PET imaging appears suitable to screen directly in vivo brain targeting of drugs or radiopharmaceutical candidates.
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Affiliation(s)
- Véronique Josserand
- Commissariat à l'Energie Atomique, Service Hospitalier Frédéric Joliot, Orsay, France
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71
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Aninat C, André F, Delaforge M. Oxidative metabolism by P450 and function coupling to efflux systems: Modulation of mycotoxin toxicity. ACTA ACUST UNITED AC 2005; 22:361-8. [PMID: 16019806 DOI: 10.1080/02652030500073287] [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: 10/23/2022]
Abstract
Man is permanently exposed to exogenous substances, either natural ones (e.g. mycotoxins, plant extracts) or man-made compounds such as pesticides or drugs. In some cases, such foreign compounds can exert either therapeutic (drugs) or toxic effects, or both. In particular, fungi are the source of a number of different secondary metabolites having such therapeutic or toxic effects. The efficiency or toxicity of foreign compounds depends on their ability to cross the cytoplasmic membrane. The exogenous molecules subsequently bind to their specific receptor in the cytoplasm or nucleus of the cell, but they are also attacked by the detoxification proteins, which in mammals are mainly composed of two types of membrane enzyme systems: cytochrome P450s, which functionalize hydrophobic xenobiotics, and an active P-glycoprotein (P-gp) transport system involved in the efflux of xenobiotics. These processes are illustrated through the use of two fungal cyclopeptides, cyclosporin A (CsA) and roquefortine C. The former, CsA, is known to be an immunosuppressor, while the latter, roquefortine C, is a potentially neurotoxic compound. CsA inhibits P-gp in a different way from its metabolites, whereas roquefortine C activates P-gp and also inhibits P450-3A and other haemoproteins. The current observations show that the two detoxification systems complement each other, resulting in a given toxicity level. The two mammal enzyme systems might therefore prove useful in the development of toxicity screening procedures.
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Affiliation(s)
- C Aninat
- Service de Pharmacologie et d'Immunologie, DRM, France
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72
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Lepper ER, Nooter K, Verweij J, Acharya MR, Figg WD, Sparreboom A. Mechanisms of resistance to anticancer drugs: the role of the polymorphic ABC transporters ABCB1 and ABCG2. Pharmacogenomics 2005; 6:115-38. [PMID: 15882131 DOI: 10.1517/14622416.6.2.115] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
ATP-binding cassette (ABC) genes play a role in the resistance of malignant cells to anticancer agents. The ABC gene products, including ABCB1 (P-glycoprotein) and ABCG2 (breast cancer-resistance protein [BCRP], mitoxantrone-resistance protein [MXR], or ABC transporter in placenta [ABCP]), are also known to influence oral absorption and disposition of a wide variety of drugs. As a result, the expression levels of these proteins in humans have important consequences for an individual’s susceptibility to certain drug-induced side effects, interactions, and treatment efficacy. Naturally occurring variants in ABC transporter genes have been identified that might affect the function and expression of the protein. This review focuses on recent advances in the pharmacogenetics of the ABC transporters ABCB1 and ABCG2, and discusses potential implications of genetic variants for the chemotherapeutic treatment of cancer.
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Affiliation(s)
- Erin R Lepper
- National Cancer Institute, Clinical Pharmacology Research Core, Building 10, Room 5A01, 9000 Rockville Pike, Bethesda, MD 20892, USA
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73
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Ono C, Takao A, Atsumi R. Absorption, distribution, and excretion of DJ-927, a novel orally effective taxane, in mice, dogs, and monkeys. Biol Pharm Bull 2005; 27:345-51. [PMID: 14993800 DOI: 10.1248/bpb.27.345] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
DJ-927, currently undergoing Phase I clinical trial, is a new orally effective taxane with potent antitumor effects. The absorption, tissue distribution, and excretion of DJ-927 were investigated in mice, dogs, and monkeys after a single oral administration. After oral administration of [14C]DJ-927, radioactivity was rapidly absorbed, with the Cmax occurring within 1-2 h in all species. The blood and plasma radioactivity elimination was biphasic and species-dependent. Elimination half-life of plasma in dogs was much longer than those in monkeys or mice. In mice, radioactivity was rapidly distributed to all tissues except for the central nervous system, especially to adrenal glands, liver, pituitary glands, kidneys, lungs, and spleen. In all species, radioactivity was mainly excreted in feces. Following a single oral administration to mice, more than 80% of the radioactivity was excreted within 48 h; in dogs and monkeys, 80% of the radioactivity was excreted within 168 h. Urinary excretion was less than 7% of radioactive dose in all species. In vitro plasma protein binding of [14C]DJ-927 in the mouse, dog, and monkey plasma ranged from 92-98%. These studies showed that, the novel oral taxane DJ-927 was rapidly absorbed in all three species when administered by the oral route. The long biological half-life and slow elimination of radioactivity were distinctive in particular, compared with commercial taxanes. DJ-927 (as parent compound and its metabolites) is widely distributed to tissues except the brain. These preclinical data are useful for the design of clinical trials of DJ-927 and also for their interpretation.
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Affiliation(s)
- Chiho Ono
- Drug Metabolism & Physicochemical Property Research Laboratory, Daiichi Pharmaceutical Co., Ltd., Kita-Kasai, Tokyo, Japan.
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74
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Abstract
Despite the established impact of highly active antiretroviral therapy (HAART) in reducing HIV-related morbidity and mortality, malignancy remains an important cause of death. Patients who receive the combination of cancer chemotherapy and HAART may achieve better response rates and higher rates of survival than patients who receive antineoplastic therapy alone. However, the likelihood of drug interactions with combined therapy is high, since protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) are substrates and potent inhibitors or inducers of the cytochrome P450 (CYP) system. Since many antineoplastic drugs are also metabolised by the CYP system, coadministration with HAART could result in either drug accumulation and possible toxicity, or decreased efficacy of one or both classes of drugs. Although formal, prospective pharmacokinetic interaction studies are not available in most instances, it is possible to infer the nature of drug interactions based on the metabolic fates of these agents. Paclitaxel and docetaxel are both metabolised by the CYP system, although differences exist in the nature of the isoenzymes involved. Case reports describing adverse consequences of concomitant taxane-antiretroviral therapy exist. Although other confounding factors may have been present, these cases serve as reminders of the vigilant monitoring necessary when taxanes and HAART are coadministered. Similarly, vinca alkaloids are substrates of CYP3A4 and are, thus, vulnerable to PI- or NNRTI-mediated changes in their pharmacokinetics. Interactions with the alkylating agents cyclophosphamide and ifosfamide are complicated as a result of the involvement of the CYP3A4 and CYP2B6 isoenzymes in both the metabolic activation of these drugs and the generation of potentially neurotoxic metabolites. Existing data regarding the metabolic fate of the anthracyclines doxorubicin and daunorubicin suggest that clinically detrimental interactions would not be expected with coadministered HAART. Commonly used endocrine therapies are largely substrates of the CYP system and may, therefore, be amenable to modulation by concomitant HAART. In addition, tamoxifen itself has been associated with reduced concentrations of both anastrozole and letrozole, raising the concern that similar inducing properties may adversely affect the outcome of PI- or NNRTI-based therapy. Similarly, dexamethasone is both a substrate and concentration-dependent inducer of CYP3A4; enhanced corticosteroid pharmacodynamics may result with CYP3A4 inhibitors, while the efficacy of concomitant HAART may be compromised with prolonged dexamethasone coadministration. Since PIs and NNRTIs may also induce or inhibit the expression of P-glycoprotein, the potential for additional interactions to arise via modulation of this transporter also exists. Further research delineating the combined safety and pharmacokinetics of antiretrovirals and antineoplastic therapy is necessary.
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75
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Lacombe O, Woodley J, Solleux C, Delbos JM, Boursier-Neyret C, Houin G. Localisation of drug permeability along the rat small intestine, using markers of the paracellular, transcellular and some transporter routes. Eur J Pharm Sci 2004; 23:385-91. [PMID: 15567292 DOI: 10.1016/j.ejps.2004.09.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Revised: 09/07/2004] [Accepted: 09/09/2004] [Indexed: 11/29/2022]
Abstract
The small intestine is the major site of drug absorption. Some reports in the literature have evoked the concept of "absorption windows" in the small intestine: are there specific regions where drug absorption is significantly higher than others? To investigate this question, we used an everted gut sac method to study the permeability of drugs and markers every 3-4cm down the entire small intestine in rat. These markers were chosen to be representative of the mechanisms by which drugs cross the small intestinal mucosa: paracellular and transcellular passive diffusion, via influx transporters, and a drug (digoxin) that is effluxed from cells by P-glycoprotein (P-gp). The passive diffusion and influx transporter markers gave similar profiles with a plateau of permeability along the jejunum, and with the exception of L-Dopa, lower permeability in the ileum. Digoxin showed a linear decrease in the profile from the proximal jejunum to the ileum. Permeability in the duodenum was two to three times lower than the jejunum for all compounds. There were no narrow specific regions of high permeability and so the concept of discrete "absorption windows" along the small intestine as suggested from some pharmacokinetic studies may be related to other effects such as pH and/or solubility.
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Affiliation(s)
- Olivier Lacombe
- Laboratoire de Cinétique des Xénobiotiques, UMR 181 Physiopathologie et Toxicologie Expérimentale (UPTE INRA-ENVT), Faculté des Sciences Pharmaceutiques, 35 chemin des Maraîchers, 31062 Toulouse Cedex, France
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76
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Shoji T, Suzuki H, Kusuhara H, Watanabe Y, Sakamoto S, Sugiyama Y. ATP-dependent transport of organic anions into isolated basolateral membrane vesicles from rat intestine. Am J Physiol Gastrointest Liver Physiol 2004; 287:G749-56. [PMID: 15217779 DOI: 10.1152/ajpgi.00065.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The mechanism for the cellular extrusion of organic anions across the intestinal basolateral membrane was examined using isolated membrane vesicles from rat jejunum, ileum, and colon. It was found that 17beta-estradiol 17beta-D-glucuronide (E217betaG) is taken up in an ATP-dependent manner into the basolateral membrane vesicles (BLMVs) but not into the brush-border or microsomal counterparts. The ATP-dependent uptake of E217betaG into BLMVs from jejunum and ileum was described by a single component with a Km value of 23.5 and 8.31 microM, respectively, whereas that into the BLMVs from colon was described by assuming the presence of high (Km=0.82 microM)- and low-affinity (Km=35.4 microM) components. Taurocholate, 6-hydroxy-5,7-dimethyl-2-methylamino-4-(3-pyridylmethyl) benzothiazole glucuronide and taurolithocholate sulfate, but not leukotriene C4, were significantly taken up by the BLMVs. In addition to such substrate specificity, the inhibitor sensitivity of the ATP-dependent transport in BLMVs was similar to that of rat multidrug resistance-associated protein 3 (Mrp3), which is located on the basolateral membrane of enterocytes. Together with the fact that the rank order of the extent of the expression of Mrp3 (jejunum < ileum << colon) is in parallel with that of the extent of the transport of ligands, these results suggest that the ATP-dependent uptake of organic anions into isolated intestinal BLMVs is at least partly mediated by Mrp3.
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Affiliation(s)
- Takahiro Shoji
- Dept. of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The Univ. of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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77
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Kuppens IELM, Bosch TM, van Maanen MJ, Rosing H, Fitzpatrick A, Beijnen JH, Schellens JHM. Oral bioavailability of docetaxel in combination with OC144-093 (ONT-093). Cancer Chemother Pharmacol 2004; 55:72-8. [PMID: 15316750 DOI: 10.1007/s00280-004-0864-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Accepted: 05/25/2004] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Docetaxel given orally as monotherapy results in low bioavailability of <10%. Previous studies have indicated that the intestinal efflux pump P-glycoprotein (P-gp) prevents uptake from the gut resulting in low systemic exposure to docetaxel. The purpose of this study was to determine the degree of enhancement of the oral uptake of docetaxel on combination with orally administered OC144-093, a potent P-gp inhibitor. Furthermore, the safety of combined treatment was determined and whether known functional genetic polymorphisms of the MDR1 gene could be associated with variability in docetaxel pharmacokinetics was also investigated. PATIENTS AND METHODS A proof of concept study was carried out in 12 patients with advanced solid tumors. Patients were randomized to receive one course of 100 mg oral docetaxel combined with 500 mg OC144-093 followed 2 weeks later by a second i.v. course of docetaxel at a flat dose of 100 mg, without OC144-093, or vice versa. This was followed by standard i.v. docetaxel treatment if indicated. RESULTS The apparent relative oral bioavailability of docetaxel was 26+/-8%. Orally administered docetaxel combined with oral OC144-093 resulted in a Cmax of 415+/-255 ng ml(-1), an AUC0-infinity of 844+/-753 ng h ml(-1) and kel of 0.810+/-0.296 h(-1). These values differed significantly from those following i.v. administration of docetaxel, with a Cmax of 2124+/-1054 ng ml(-1), an AUC0-infinity of 2571+/-1598 ng h ml(-1) and a kel of 1.318+/-0.785 h(-1) (P=0.003, P=0.006, P=0.016). The study medication was well tolerated and most of the adverse events possibly or probably related to OC144-093 and docetaxel were of CTC grade 1 and 2. One patient had a homozygous 3435T/T mutation, which is associated with low intestinal P-gp expression, and two other patients had a homozygous mutation on exon 21. CONCLUSION The relative apparent bioavailability of 26% was most likely caused by a significant effect of OC144-093 on the oral uptake of docetaxel. Large intrapatient and interpatient (pharmacokinetic) variation was found after oral as well as after i.v. administration of docetaxel. Higher plasma levels were observed after 100 mg i.v. docetaxel than after 100 mg oral docetaxel plus 500 mg oral OC144-093. The safety of the oral combination was good. More patients should be evaluated to determine the effect of P-gp single nucleotide polymorphisms on oral pharmacokinetic values of docetaxel.
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Affiliation(s)
- I E L M Kuppens
- Department of Medical Oncology, Antoni van Leeuwenhoek Hospital/The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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Blanchette J, Kavimandan N, Peppas NA. Principles of transmucosal delivery of therapeutic agents. Biomed Pharmacother 2004; 58:142-51. [PMID: 15082336 DOI: 10.1016/j.biopha.2004.01.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2004] [Indexed: 11/16/2022] Open
Abstract
Recent advances in medicine have led to new treatment options for patients and physicians as a more developed understanding of the molecular basis of disease states is translated into new therapeutic agents. Many of these new agents are compounds that are not able to reach the bloodstream when administered by the oral route preventing the ability to enjoy the benefits this delivery route provides such as lower cost and increased quality of life. Our laboratory has focused on the use of hydrogel carriers to increase the bioavailability of orally administered therapeutic agents ranging from proteins such as insulin to chemotherapeutics like bleomycin. The foundations of this research as well as recent advances are reviewed along with a discussion of the challenges of oral administration and other emerging strategies for oral administration.
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Affiliation(s)
- James Blanchette
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, USA
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80
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Kim DW, Kwon JS, Kim YG, Kim MS, Lee GS, Youn TJ, Cho MC. Novel oral formulation of paclitaxel inhibits neointimal hyperplasia in a rat carotid artery injury model. Circulation 2004; 109:1558-63. [PMID: 15006998 DOI: 10.1161/01.cir.0000124063.74526.be] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Paclitaxel has been shown to inhibit vascular smooth muscle cell migration and proliferation contributing to neointimal formation. This study tested whether novel oral formulations of paclitaxel can prevent neointimal formation in a rat carotid artery injury model. METHODS AND RESULTS Oral formulations of paclitaxel (0, 5, 7.5, or 10 mg/kg) were administered to 40 rats by gavage for 5 days after injury. The peak plasma levels of paclitaxel administered at 5, 7.5, and 10 mg/kg were 61+/-16, 89+/-22, and 108+/-28 nmol/L, respectively. Treatment effects were assessed 11 days after injury. The angiographic minimum luminal diameters of the oral paclitaxel groups treated at 5, 7.5, and 10 mg/kg were 6.28+/-2.09, 6.97+/-1.79, and 7.97+/-1.57 AU, and these were significantly larger than that of the control group (4.67+/-1.45 AU). The oral paclitaxel groups (5, 7.5, 10 mg/kg; 0.05+/-0.05, 0.04+/-0.03, 0.05+/-0.03 mm2) showed significant neointimal formation reductions versus the control group (0.13+/-0.05 mm2). All rats survived to study completion. Only 2 animals in the 10 mg/kg group experienced weight loss ( approximately 10%) and loose stools between 4 and 6 days after injury. All other animals appeared healthy during the study. For comparison purposes, intraperitoneal formulations of paclitaxel (0 or 2 mg/kg) were administered by injection to 15 rats. We confirmed that the intraperitoneal administration of paclitaxel also effectively inhibited neointimal formation. CONCLUSIONS Oral formulations of paclitaxel provide an effective means of inhibiting proliferative response to vascular injury in the rat. Thus, oral formulations of paclitaxel may prevent human restenosis without significant toxicity.
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Affiliation(s)
- Dong-Woon Kim
- Department of Internal Medicine, Chungbuk National University, Cheongju, Korea.
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81
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Lyu SY, Kwon YJ, Joo HJ, Park WB. Preparation of alginate/chitosan microcapsules and enteric coated granules of mistletoe lectin. Arch Pharm Res 2004; 27:118-26. [PMID: 14969350 DOI: 10.1007/bf02980057] [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: 11/29/2022]
Abstract
The aqueous extract of European mistletoe (Viscum album, L.) has been used in cancer therapy. The purified mistletoe lectins, main components of mistletoe, have demonstrated cytotoxic and immune-system-stimulating activities. Korean mistletoe (Viscum album L. coloratum), a subspecies of European mistletoe, has also been reported to possess anticancer and immunological activities. A galactose- and N-acetyl-D-galactosamine-specific lectin (Viscum album L. coloratum agglutinin, VCA) with Mr 60 kDa was isolated from Korean mistletoe. Mistletoe preparations have been given subcutaneously due to the low stability of lectin in the gastrointestinal (GI) tract. In the present study, we investigated the possibility of alginate/chitosan microcapsules as a tool for oral delivery of mistletoe lectin. In addition, our strategy has been to develop a system composed of stabilizing cores (granules), which contain mistletoe lectin, extract or powder, coated by a biodegradable polymer wall. Our results indicated that successful incorporation of VCA into alginate/chitosan microcapsules has been achieved and that the alginate/chitosan microcapsule protected the VCA from degradation at acidic pH values. And coating the VCA with polyacrylic polymers, Eudragit, produced outstanding results with ideal release profiles and only minimal losses of cytotoxicity after manufacturing step. The granules prepared with extract or whole plant produced the best results due to the stability in the extract or whole plant during manufacturing process.
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Affiliation(s)
- Su-Yun Lyu
- College of Natural Sciences, Seoul Womens University, Seoul 139-774, Korea
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82
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McEntee M, Silverman JA, Rassnick K, Zgola M, Chan AO, Tau PT, Page RL. Enhanced bioavailability of oral docetaxel by co-administration of cyclosporin A in dogs and rats. Vet Comp Oncol 2003; 1:105-12. [DOI: 10.1046/j.1476-5829.2003.00015.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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83
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Granvil CP, Yu AM, Elizondo G, Akiyama TE, Cheung C, Feigenbaum L, Krausz KW, Gonzalez FJ. Expression of the human CYP3A4 gene in the small intestine of transgenic mice: in vitro metabolism and pharmacokinetics of midazolam. Drug Metab Dispos 2003; 31:548-58. [PMID: 12695342 DOI: 10.1124/dmd.31.5.548] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Human cytochrome P450 3A4 (CYP3A4) is the most abundant hepatic and intestinal phase I drug-metabolizing enzyme, and participates in the oxidative metabolism of approximately 50% of drugs on the market. In the present study, a transgenic-CYP3A4 (Tg-CYP3A4) mouse model that expresses CYP3A4 in the intestine and is phenotypically normal was generated, which was genotyped by both polymerase chain reaction and Southern blotting. Intestinal microsomes prepared from Tg-CYP3A4 mice metabolized midazolam (MDZ) to 1'-hydroxymidazolam about 2 times, and to 4-hydroxymidazolam around 3 times faster than that from wild-type (WT) mice. These increased MDZ hydroxylation activities were completely inhibited by an anti-CYP3A4 monoclonal antibody. The time course of plasma MDZ and its metabolite concentrations was measured after intravenous (0.25 mg/kg) and oral (2.5 mg/kg) administration of MDZ, and pharmacokinetic parameters were estimated by fitting to a noncompartmental model. Pretreatment with ketoconazole increased orally dosed MDZ maximum plasma concentration (C(max)), time of the maximum concentration, area under the plasma concentration-time curve from zero to infinity (AUC(0- infinity)), and elimination half-life (t(1/2)) to 3.2-, 1.7-, 7.7-, 2-fold, and decreased MDZ apparent oral clearance about 8-fold in Tg-CYP3A4 mice. The ratios of MDZ C(max), AUC(0- infinity), t(1/2) and bioavailability between Tg-CYP3A4 and WT mice after the oral dose of MDZ were 0.3, 0.6, 0.5, and 0.5, respectively. These results suggest that this Tg-CYP3A4 mouse would be an appropriate in vivo animal model for the evaluation of human intestine CYP3A4 metabolism of drug candidates and potential food-drug and drug-drug interactions in preclinical drug development.
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Affiliation(s)
- Camille P Granvil
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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84
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Sparreboom A, Danesi R, Ando Y, Chan J, Figg WD. Pharmacogenomics of ABC transporters and its role in cancer chemotherapy. Drug Resist Updat 2003; 6:71-84. [PMID: 12729805 DOI: 10.1016/s1368-7646(03)00005-0] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
ATP-binding cassette (ABC) genes play a role in the resistance of malignant cells to anticancer agents. The ABC gene products, including ABCB1 (P-glycoprotein), ABCC1 (MRP1), ABCC2 (MRP2, cMOAT), and ABCG2 (BCRP, MXR, ABCP) are also known to influence oral absorption and disposition of a wide variety of drugs. As a result, the expression levels of these proteins in humans have important consequences for an individual's susceptibility to certain drug-induced side effects, interactions, and treatment efficacy. Naturally occurring variants in ABC transporter genes have been identified that might affect the function and expression of the protein. This review focuses on recent advances in the pharmacogenomics of ABC transporters, and discusses potential implications of genetic variants for the chemotherapeutic treatment of cancer.
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Affiliation(s)
- Alex Sparreboom
- Clinical Pharmacology Research Core, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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85
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Abstract
A resurgence in the use of medical herbs in the Western world, and the co-use of modern and traditional therapies is becoming more common. Thus there is the potential for both pharmacokinetic and pharmacodynamic herb-drug interactions. For example, systems such as the cytochrome P450 (CYP) may be particularly vulnerable to modulation by the multiple active constituents of herbs, as it is well known that the CYPs are subject to induction and inhibition by exposure to a wide variety of xenobiotics. Using in vitro, in silico, and in vivo approaches, many herbs and natural compounds isolated from herbs have been identified as substrates, inhibitors, and/or inducers of various CYP enzymes. For example, St. John's wort is a potent inducer of CYP3A4, which is mediated by activating the orphan pregnane X receptor. It also contains ingredients that inhibit CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. Many other common medicinal herbs also exhibited inducing or inhibiting effects on the CYP system, with the latter being competitive, noncompetitive, or mechanism-based. It appears that the regulation of CYPs by herbal products complex, depending on the herb type, their administration dose and route, the target organ and species. Due to the difficulties in identifying the active constituents responsible for the modulation of CYP enzymes, prediction of herb-drug metabolic interactions is difficult. However, herb-CYP interactions may have important clinical and toxicological consequences. For example, induction of CYP3A4 by St. John's wort may partly provide an explanation for the enhanced plasma clearance of a number of drugs, such as cyclosporine and innadivir, which are known substrates of CYP3A4, although other mechanisms including modulation of gastric absorption and drug transporters cannot be ruled out. In contrast, many organosulfur compounds, such as diallyl sulfide from garlic, are potent inhibitors of CYP2E1; this may provide an explanation for garlic's chemoproventive effects, as many mutagens require activation by CYP2E1. Therefore, known or potential herb-CYP interactions exist, and further studies on their clinical and toxicological roles are warranted. Given that increasing numbers of people are exposed to a number of herbal preparations that contain many constituents with potential of CYP modulation, high-throughput screening assays should be developed to explore herb-CYP interactions.
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Affiliation(s)
- Shufeng Zhou
- Department of Pharmacy, Faculty of Science, National University of Singapore, Republic of Singapore.
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Abstract
The ATP-binding cassette (ABC) transporters are a family of large proteins in membranes and are able to transport a variety of compounds through membranes against steep concentration gradients at the cost of ATP hydrolysis. The available outline of the human genome contains 48 ABC genes; 16 of these have a known function and 14 are associated with a defined human disease. Major physiological functions of ABC transporters include the transport of lipids, bile salts, toxic compounds, and peptides for antigen presentation or other purposes. We review the functions of mammalian ABC transporters, emphasizing biochemical mechanisms and genetic defects. Our overview illustrates the importance of ABC transporters in human physiology, toxicology, pharmacology, and disease. We focus on three topics: (a) ABC transporters transporting drugs (xenotoxins) and drug conjugates. (b) Mammalian secretory epithelia using ABC transporters to excrete a large number of substances, sometimes against a steep concentration gradient. Several inborn errors in liver metabolism are due to mutations in one of the genes for these pumps; these are discussed. (c) A rapidly increasing number of ABC transporters are found to play a role in lipid transport. Defects in each of these transporters are involved in human inborn or acquired diseases.
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Affiliation(s)
- P Borst
- Division of Molecular Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
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87
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Suzuki H, Sugiyama Y. Single nucleotide polymorphisms in multidrug resistance associated protein 2 (MRP2/ABCC2): its impact on drug disposition. Adv Drug Deliv Rev 2002; 54:1311-31. [PMID: 12406647 DOI: 10.1016/s0169-409x(02)00075-3] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Multidrug resistance associated protein 2 (MRP2/ABCC2), expressed on the bile canalicular membrane, plays an important role in the biliary excretion of various kinds of substrates. In addition, MRP2 is also expressed on the apical membrane of epithelial cells such as enterocytes. It is possible that the inter-individual difference in the function of MRP2 affects the drug disposition. In the present article, we will summarize the physiological and pharmacological role of MRP2, particularly focusing on the factors affecting its transport function such as single nucleotide polymorphisms and/or the induction/down regulation of this transporter. Mutations found in patients suffering from the Dubin-Johnson syndrome, along with the amino acid residues which are involved in supporting the transport activity of MRP2, are also summarized.
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Affiliation(s)
- Hiroshi Suzuki
- School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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88
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Abstract
Rapid development in molecular biology and recent advancement in recombinant technology increase identification and commercialization of potential protein drugs. Traditional forms of administrations for the peptide and protein drugs often rely on their parenteral injection, since the bioavailability of these therapeutic agents is poor when administered nonparenterally. Tremendous efforts by numerous investigators in the world have been put to improve protein formulations and as a result, a few successful formulations have been developed including sustained-release human growth hormone. For a promising protein delivery technology, efficacy and safety are the first requirement to meet. However, these systems still require periodic injection and increase the incidence of patient compliance. The development of an oral dosage form that improves the absorption of peptide and especially protein drugs is the most desirable formulation but one of the greatest challenges in the pharmaceutical field. The major barriers to developing oral formulations for peptides and proteins are metabolic enzymes and impermeable mucosal tissues in the intestine. Furthermore, chemical and conformational instability of protein drugs is not a small issue in protein pharmaceuticals. Conventional pharmaceutical approaches to address these barriers, which have been successful with traditional organic drug molecules, have not been effective for peptide and protein formulations. It is likely that effective oral formulations for peptides and proteins will remain highly compound specific. A number of innovative oral drug delivery approaches have been recently developed, including the drug entrapment within small vesicles or their passage through the intestinal paracellular pathway. This review provides a summary of the novel approaches currently in progress in the protein oral delivery followed by factors affecting protein oral absorption.
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Affiliation(s)
- Hye J Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Kwanak-Gu, Korea.
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89
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Sarver JG, Klis WA, Byers JP, Erhardt PW. Microplate screening of the differential effects of test agents on Hoechst 33342, rhodamine 123, and rhodamine 6G accumulation in breast cancer cells that overexpress P-glycoprotein. JOURNAL OF BIOMOLECULAR SCREENING 2002; 7:29-34. [PMID: 11897053 DOI: 10.1177/108705710200700105] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A microplate screening method has been developed to evaluate the effects of test agents on the accumulation of the fluorescent P-glycoprotein (Pgp) substrates Hoechst 33342, rhodamine 123, and rhodamine 6G in multidrug-resistant (MDR) breast cancer cells that overexpress Pgp. All three substrates exhibit substantially higher accumulation in MCF7 non-MDR cells versus NCI/ADR-RES MDR cells, while incubation with 50 microM reserpine significantly reduces or eliminates these differences. Rhodamine 123 shows the lowest substrate accumulation efficiency in non-MDR cells relative to the substrate incubation level. The effects of several chemosensitizing agents and a series of paclitaxel analogs on the accumulation of each fluorescent substrate suggest that there are distinct differences in the substrate interaction profiles exhibited by these different agents. The described methods may be useful in Pgp-related research in the areas of cancer MDR, oral drug absorption, the blood-brain barrier, renal/hepatic transport processes, and drug-drug interactions.
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Affiliation(s)
- Jeffrey G Sarver
- Center for Drug Design and Development, The University of Toledo College of Pharmacy, Toledo, OH 43606, USA.
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90
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Sparreboom A, de Jonge MJA, Verweij J. The use of oral cytotoxic and cytostatic drugs in cancer treatment. Eur J Cancer 2002; 38:18-22. [PMID: 11750835 DOI: 10.1016/s0959-8049(01)00322-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Although with a few exceptions, most new anticancer agents are initially developed for intravenous use, oral treatment with anticancer agents is, if feasible, to be preferred, as this route of administration is convenient to patients, reduces administration costs and facilitates the use of more chronic treatment regimens. Recent studies have identified various physiological barriers limiting the oral absorption of anticancer drugs. Presently, several strategies are explored to alter the low and variable oral bioavailability of several important anticancer agents by taking advantage of an intentional interaction between anticancer agents and drugs that modulate active intestinal drug transporters or (intestinal) enzymes.
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Affiliation(s)
- A Sparreboom
- Department of Medical Oncology, Rotterdam Cancer Institute (Daniel den Hoed Kliniek) and University Hospital Rotterdam, 3075 EA Rotterdam, The Netherlands.
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91
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Patel J, Mitra AK. Strategies to overcome simultaneous P-glycoprotein mediated efflux and CYP3A4 mediated metabolism of drugs. Pharmacogenomics 2001; 2:401-15. [PMID: 11722289 DOI: 10.1517/14622416.2.4.401] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cytochrome P450 3A4 (CYP3A4), abundant in both the liver and upper intestinal enterocytes, limits the systemic bioavailability of xenobiotics. P-glycoprotein (P-gp), the MDR1 gene product, is also known to reduce the oral bioavailability of the drug molecules. High cellular expression of P-gp and CYP3A4 in mature intestinal enterocytes and their similar substrate specificity suggest that the function of these proteins may be complementary and may form a co-ordinated intestinal barrier. Various ongoing preclinical and clinical studies have demonstrated that the oral bioavailability of various P-gp and/or CYP3A4 substrates can be increased by simultaneous administration of P-gp and/or CYP3A4 inactivators. The current review describes the background and summarises several proposed hypotheses in modifying oral bioavailability by various drug-inhibitor interactions.
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Affiliation(s)
- J Patel
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005 Rockhill Road, Kansas City, MO 64110, USA
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