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Martinez MN, Papich MG. Factors influencing the gastric residence of dosage forms in dogs. J Pharm Sci 2009; 98:844-60. [PMID: 18661535 DOI: 10.1002/jps.21499] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An appreciation of the variables influencing canine gastric transit time is of interest both because of the push to develop pharmaceutical products that meet the therapeutic needs of the veterinary patient and because of efforts to improve our understanding of the strengths and weaknesses associated with the use of the dog as a preclinical model to support human product development. The gastric transit time of monogastric species is influenced by many factors. Physiological variables include the time of dosing relative to the phase of the interdigestive migrating myoelectric current (IMMC), the sieving properties of the pylorus, the presence or absence of food, and the inherent crushing force of the stomach. Pharmacological factors include particle size, shape and density, drug solubility, and the hardness of the tablet. Despite the importance of understanding the factors influencing gastric residence time in dogs, an in-depth examination of currently available information on this topic has not as yet been published. Therefore, this review provides an examination of each of these factors and their potential impact on canine oral drug absorption characteristics.
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Affiliation(s)
- Marilyn N Martinez
- US Food and Drug Administration, Center for Veterinary Medicine, Office of New Animal Drug Evaluation, 7500 Standish Place, Rockville, Maryland 20855, USA.
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52
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Tanno FK, Sakuma S, Masaoka Y, Kataoka M, Kozaki T, Kamaguchi R, Ikeda Y, Kokubo H, Yamashita S. Site-specific drug delivery to the middle-to-lower region of the small intestine reduces food-drug interactions that are responsible for low drug absorption in the fed state. J Pharm Sci 2009; 97:5341-53. [PMID: 18386838 DOI: 10.1002/jps.21382] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Food-drug interactions may reduce the bioavailability of drugs taken after meals (negative food effects). We designed enteric-coated tablets that start to disintegrate when they reach the middle-to-lower region of the small intestine, and examined whether they could reduce negative food effects in dogs. Tablets containing trientine as a model drug were coated with hypromellose acetate succinate (HPMCAS) with various values of succinoyl group content. The time lag of drug dissolution from these enteric-coated tablets in simulated intestinal fluid of pH 6.8 increased as the succinoyl group content was decreased. The AUC of trientine after oral administration of its aqueous solution to fed dogs was one-eighth of that in fasted dogs. The low drug absorption in fed dogs was improved when trientine was administered as enteric-coated tablets. The average ratio of AUC in the fed state to that in the fasted state increased with decreasing succinoyl group content of HPMCAS. Negative food effects completely disappeared after oral administration of tablets coated with HPMCAS having a succinoyl group content of 6.2% or less, which probably disintegrated in the middle-to-lower small intestine. Our results indicated that food-drug interactions were avoided by separating the main absorption site of drugs from that of food components.
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Affiliation(s)
- Fumié K Tanno
- Specialty Chemicals Research Center, Shin-Etsu Chemical Co., Ltd, 28-1, Nishifukushima, Kubiki-ku, Joetsu, Niigata 942-8601, Japan
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53
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Tanno FK, Sakuma S, Masaoka Y, Kataoka M, Kozaki T, Kamaguchi R, Ikeda Y, Kokubo H, Yamashita S. Site‐Specific Drug Delivery to the Middle Region of the Small Intestine by Application of Enteric Coating with Hypromellose Acetate Succinate (HPMCAS). J Pharm Sci 2008; 97:2665-79. [PMID: 17828736 DOI: 10.1002/jps.21172] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Enteric coatings that deliver drugs to specific regions of the small intestine were examined. Hypromellose acetate succinate (HPMCAS) with different values of succinoyl group contents was used. Decreasing the succinoyl group content resulted in an increase in the pH at which HPMCAS started to dissolve. Drug-containing granules with or without enteric coating were prepared and their in vitro dissolution in a simulated intestinal fluid of pH 6.8 was examined. Granules coated with HPMCAS having the succinoyl group content of 6.2% showed a lag time of about 30 min, although drug release from granules without coating was completed within 20 min. The time lag and dissolution rate were extended and reduced, respectively, as the succinoyl group content was decreased. Rat experiments indicated that enteric-coated granules disintegrated and the bulk of the drugs was immediately released when the granules reached a specific site of the small intestine where the pH corresponded to the pH at which the enteric coating agent started to dissolve. Similar results were observed in monkey experiments. It was suggested that HPMCAS with the succinoyl group content of about 5% was suitable as an enteric coating agent for delivering drugs to the middle-to-lower region of the small intestine.
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Affiliation(s)
- Fumié K Tanno
- Specialty Chemicals Research Center, Shin-Etsu Chemical Co, Ltd, 28-1, Nishifukushima, Joetsu, Niigata, Japan
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54
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In Vivo Performance of an Oral MR Matrix Tablet Formulation in the Beagle Dog in the Fed and Fasted State: Assessment of Mechanical Weakness. Pharm Res 2007; 25:1075-84. [DOI: 10.1007/s11095-007-9462-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Accepted: 09/20/2007] [Indexed: 10/22/2022]
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Sugano K, Okazaki A, Sugimoto S, Tavornvipas S, Omura A, Mano T. Solubility and dissolution profile assessment in drug discovery. Drug Metab Pharmacokinet 2007; 22:225-54. [PMID: 17827779 DOI: 10.2133/dmpk.22.225] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The purposes of the review are to: a) Provide a comprehensible introduction of the-state-of-the-art sciences of solubility and dissolution, b) introduce typical technologies to assess solubility and dissolution, and c) propose the best practice strategy. The theories of solubility and dissolution required in drug discovery were reviewed especially from the view point of oral absorption. The physiological conditions in the gastrointestinal fluid in humans and animals were then briefly summarized. Technologies to assess solubility and dissolution in drug discovery were then introduced. Recently, these technologies have been improved by the laboratory automation and computational technologies. Finally, the strategies to apply these technologies for a drug discovery project were discussed.
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Affiliation(s)
- Kiyohiko Sugano
- Global Research & Development, Nagoya Laboratories, Pharmaceutical R&D, Pfizer Inc., Aichi, Japan.
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56
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Ghimire M, McInnes FJ, Watson DG, Mullen AB, Stevens HNE. In-vitro/in-vivo correlation of pulsatile drug release from press-coated tablet formulations: A pharmacoscintigraphic study in the beagle dog. Eur J Pharm Biopharm 2007; 67:515-23. [PMID: 17498934 DOI: 10.1016/j.ejpb.2007.03.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 03/01/2007] [Accepted: 03/05/2007] [Indexed: 11/29/2022]
Abstract
The aim of the current study was to investigate the in-vitro and in-vivo performance of a press-coated tablet (PCT) intended for time delayed drug release, consisting of a rapidly disintegrating theophylline core tablet, press-coated with barrier granules containing glyceryl behenate (GB) and low-substituted hydroxypropylcellulose (L-HPC). The PCTs showed pulsatile release with a lag time dependent upon the GB and L-HPC composition of the barrier layer. In-vivo gamma-scintigraphic studies were carried out for PCTs containing GB:L-HPC at 65:35 w/w and 75:25 w/w in the barrier layer in four beagle dogs, in either the fed or fasted state. The in-vivo lag time in both the fed and fasted states did not differ significantly (p>0.05) from the in-vitro lag time. Additionally, no significant difference (p<0.05) between in-vivo fed and fasted disintegration times was observed, demonstrating that in-vivo performance of the PCT was not influenced by the presence or absence of food in the gastrointestinal tract. A distinct lag time was obtained prior to the appearance of drug in plasma and correlated (R2=0.98) with disintegration time observed from scintigraphic images. However, following disintegration, no difference in pharmacokinetic parameters (AUC(0-6 dis), K(el), Cmax) was observed. The current study highlighted the potential use of these formulations for chronopharmaceutical drug delivery.
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Affiliation(s)
- Manish Ghimire
- University of Strathclyde, Strathclyde Institute of Pharmacy and Biomedical Sciences, Glasgow, United Kingdom
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57
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Raekallio MR, Honkavaara JM, Säkkinen MS, Peltoniemi SM. Effects of urine alkalization and activated charcoal on the pharmacokinetics of orally administered carprofen in dogs. Am J Vet Res 2007; 68:423-7. [PMID: 17397299 DOI: 10.2460/ajvr.68.4.423] [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] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the effects of oral administration of activated charcoal (AC) and urine alkalinization via oral administration of sodium bicarbonate on the pharmacokinetics of orally administered carprofen in dogs. ANIMALS 6 neutered male Beagles. PROCEDURES Each dog underwent 3 experiments (6-week interval between experiments). The dogs received a single dose of carprofen (16 mg/kg) orally at the beginning of each experiment; after 30 minutes, sodium bicarbonate (40 mg/kg, PO), AC solution (2.5 g/kg, PO), or no other treatments were administered. Plasma concentrations of unchanged carprofen were determined via high-performance liquid chromatography at intervals until 48 hours after carprofen administration. Data were analyzed by use of a Student paired t test or Wilcoxon matched-pairs rank test. RESULTS Compared with the control treatment, administration of AC decreased plasma carprofen concentrations (mean +/- SD maximum concentration was 85.9 +/- 11.9 mg/L and 58.1 +/- 17.6 mg/L, and area under the time-concentration curve was 960 +/- 233 mg/L x h and 373 +/- 133 mg/L x h after control and AC treatment, respectively). The elimination half-life remained constant. Administration of sodium bicarbonate had no effect on plasma drug concentrations. CONCLUSIONS AND CLINICAL RELEVANCE After oral administration of carprofen in dogs, administration of AC effectively decreased maximum plasma carprofen concentration, compared with the control treatment, probably by decreasing carprofen absorption. Results suggest that AC can be used to reduce systemic carprofen absorption in dogs receiving an overdose of carprofen. Oral administration of 1 dose of sodium bicarbonate had no apparent impact on carprofen kinetics in dogs.
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Affiliation(s)
- Marja R Raekallio
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, FIN-00014, Finland
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58
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Gibbons PM, Tell LA, Kass PH, Christopher MM. Evaluation of the sensitivity and specificity of four laboratory tests for detection of occult blood in cockatiel (Nymphicus hollandicus) excrement. Am J Vet Res 2006; 67:1326-32. [PMID: 16881843 DOI: 10.2460/ajvr.67.8.1326] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare sensitivity and specificity of cytologic examination and 3 chromogen tests for detection of occult blood in cockatiel (Nymphicus hollandicus) excrement. ANIMALS 20 adult cockatiels. PROCEDURES Pooled blood from birds was divided into whole blood and lysate aliquots. Excrement was mixed with each aliquot in vitro to yield 6 hemoglobin (Hb) concentrations (range, 0.375 to 12.0 mg of Hb/g of excrement). For the in vivo portion of the study, birds were serially gavaged with each aliquot separately at 5 doses of Hb (range, 2.5 to 40 mg/kg). Three chromogen tests and cytologic examination were used to test excrement samples for occult blood. Sensitivity, specificity, and observer agreement were calculated. RESULTS In vitro specificity ranged from 85%to 100% for the 3 chromogen tests and was 100% for cytologic examination. Sensitivity was 0% to 35% for cytologic examination and 100% for the 3 chromogen tests on samples containing >or= 1.5 mg of Hb/g of excrement. In vivo specificity was 100%, 90%, 65%, and 45% for cytologic examination and the 3 chromogen tests, respectively. Sensitivity was 0% to 5% for cytologic examination and >or= 75% for all 3 chromogen tests after birds received doses of Hb >or= 20 mg/kg. Observer agreement was lowest for cytologic examination. CONCLUSIONS AND CLINICAL RELEVANCE Chromogen tests were more useful than cytologic examination for detection of occult blood in cockatiel excrement. The best combination of sensitivity, specificity, and observer agreement was obtained by use of a chromogen test.
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Affiliation(s)
- Paul M Gibbons
- Companion Avian and Exotic Pet Medicine Service, Veterinary Medical Teaching Hospital, Davis, CA 95616, USA
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Kuentz M, Nick S, Parrott N, Röthlisberger D. A strategy for preclinical formulation development using GastroPlus™ as pharmacokinetic simulation tool and a statistical screening design applied to a dog study. Eur J Pharm Sci 2006; 27:91-9. [PMID: 16219449 DOI: 10.1016/j.ejps.2005.08.011] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 08/11/2005] [Accepted: 08/20/2005] [Indexed: 11/16/2022]
Abstract
The aim of this paper is to propose a pharmaceutical risk assessment strategy that goes beyond the usual characterisation of a clinical candidate molecule according to the biopharmaceutical classification system (BCS). This strategy was evaluated for a new CNS drug with poor solubility and good permeability. In a first step, GastroPlus was used to simulate the absorption process based on preformulation data. These input data involved a physicochemical drug characterisation including drug solubility measurements in simulated physiological media, as well as permeability determination. Further computer simulations were conducted to determine the sensitivity to changes of selected input values. Thus, oral bioavailability prediction was studied as a function of the particle size and drug solubility. The second part of the presented strategy for preclinical formulation development was to test specially designed formulations in a 2(3) screening factorial plan using the dog as the animal model. The factors were the dosage form, food effect and dose strength. One of the two experimental formulations was a capsule filled with the micronised drug, whereas the other formulation was a surfactant solution of the drug. Accordingly, a "worst case" formulation was compared with a "best case" drug solution over the clinically relevant dose range in fasted and fed dogs. The results of the computer simulation indicated that a fraction of the dose is dissolved in the stomach and precipitates partially in the small intestine. The simulation predicted almost full drug absorption during the GI transit time. Interestingly, the simulation implies that stomach drug solubility had little impact on overall fraction absorbed. The results also showed that changes of particle size and reference solubility within two orders of magnitude hardly affected the oral bioavailability. This in silico deduction was subsequently compared with the results of the dog studies. Indeed a surfactant drug solution showed no clear biopharmaceutical superiority over a solid capsule formulation on the average of both dose strengths in fasted and fed dogs. Despite the substantial variability of the in vivo data, the factorial screening design indicated marginal significant interaction between the dose level and feeding status. This can be viewed as a flag for the planning of further studies, since a potential effect of one factor may depend on the level of the other. In summary, the GastroPlus simulation together with the statistically designed dog study provided a thorough biopharmaceutical assessment of the new CNS drug. Based on these findings, it was decided to develop a standard granulate in capsules for phase I studies. More sophisticated formulation options were abandoned and so the clinical formulation development was conducted in a cost-efficient way.
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Affiliation(s)
- Martin Kuentz
- F. Hoffmann-La Roche Ltd., Pharmaceutical and Analytical R&D, Bldg./Lab. 072/338, Grenzacherstrasse, CH-4070 Basel, Switzerland.
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60
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Thombre AG. Assessment of the feasibility of oral controlled release in an exploratory development setting. Drug Discov Today 2005; 10:1159-66. [PMID: 16182208 DOI: 10.1016/s1359-6446(05)03551-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Controlled release (CR) formulations have generally been considered as follow-ons to conventional immediate release formulations to manage the life cycle of a product. Although significant opportunities exist to use CR as an enabling technology for certain exploratory drug candidates, they have not been fully exploited. However, progress made in assessing CR feasibility based on the physicochemical and biopharmaceutical properties of the drug, together with advances made in understanding the various CR technologies and developing formulations in a fast and efficient manner, have increasingly made it possible to consider CR in an exploratory development setting.
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Schulze JDR, Peters EE, Vickers AW, Staton JS, Coffin MD, Parsons GE, Basit AW. Excipient effects on gastrointestinal transit and drug absorption in beagle dogs. Int J Pharm 2005; 300:67-75. [PMID: 15979264 DOI: 10.1016/j.ijpharm.2005.05.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Revised: 05/16/2005] [Accepted: 05/17/2005] [Indexed: 11/15/2022]
Abstract
Previous work has shown that polyethylene glycol 400 (PEG 400) has an accelerating effect on gastrointestinal transit and a modulating influence on drug absorption in humans. The aim of this study was to assess the impact of various excipients, PEG 400, propylene glycol, d-alpha-tocopheryl-polyethylene glycol-1000 succinate (TPGS) and Labrasol on gastrointestinal transit and drug absorption in four beagle dogs using scintigraphy. Each dog received, on five separate occasions, water (control) or a dose of excipient equivalent to 1 g PEG 400, 2 g propylene glycol, 1 g TPGS or 2 g Labrasol dissolved in water and administered in the form of two capsules. The model drugs ampicillin (200mg) and antipyrine (100mg) were co-administered in the capsules. The capsule solutions were radiolabelled with technetium-99m to follow their transit using a dual-headed gamma camera, and blood samples were collected to determine drug pharmacokinetics. On a separate occasion, the drugs were dissolved in saline and given intravenously. The capsules rapidly disintegrated in the stomach liberating their liquid contents. The mean small intestinal transit times for the different treatments (control, PEG 400, propylene glycol, TPGS and Labarasol) were 183, 179, 195, 168 and 154 min, respectively. The corresponding mean absolute oral bioavailability figures were 36, 32, 39, 42 and 32% for ampicillin and 76, 74, 85, 73 and 74% for antipyrine, respectively. The transit and bioavailability data for the excipient treatments were not significantly different from the control. In summary, these excipients, at the doses administered, have limited influence on gastrointestinal transit and drug in beagle dogs.
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Affiliation(s)
- Julia D R Schulze
- Department of Pharmaceutics, The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK
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