A Theoretical Basis for a Biopharmaceutic Drug Classification: The Correlation of in Vitro Drug Product Dissolution and in Vivo Bioavailability
Abstract
A biopharmaceutics drug classification scheme for correlating in vitro drug product dissolution and in vivo bioavailability is proposed based on recognizing that drug dissolution and gastrointestinal permeability are the fundamental parameters controlling rate and extent of drug absorption. This analysis uses a transport model and human permeability results for estimating in vivo drug absorption to illustrate the primary importance of solubility and permeability on drug absorption. The fundamental parameters which define oral drug absorption in humans resulting from this analysis are discussed and used as a basis for this classification scheme. These Biopharmaceutic Drug Classes are defined as: Case 1. High solubility-high permeability drugs, Case 2. Low solubility-high permeability drugs, Case 3. High solubility-low permeability drugs, and Case 4. Low solubility-low permeability drugs. Based on this classification scheme, suggestions are made for setting standards for in vitro drug dissolution testing methodology which will correlate with the in vivo process. This methodology must be based on the physiological and physical chemical properties controlling drug absorption. This analysis points out conditions under which no in vitro-in vivo correlation may be expected e.g. rapidly dissolving low permeability drugs. Furthermore, it is suggested for example that for very rapidly dissolving high solubility drugs, e.g. 85% dissolution in less than 15 minutes, a simple one point dis…
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Gastroparesis caused by non-pharmacologic etiologies affects drug absorption.
“Gastroparesis caused by non-pharmacologic etiologies is indeed known to affect drug absorption [6, 7].”
From Drug-Drug Interactions Between Glucagon-Like Peptide 1 Receptor Agonists and Oral Medications: A Systematic Review (2024) · cites this paper as [6]
Application of the BCS in waiving BA/BE requirements is based on premises that if two immediate-release drug formulations/products behave as oral solutions within the GI tract due to high solubility and rapid dissolution, no precipitation occurs in the GI tract once the API is dissolved, and the two IR formulations have the same in vivo dissolution profile under all intestinal luminal conditions,则
“Application of the BCS in waiving BA/BE requirements is based on premises that if (1) two immediate-release (IR) drug formulations/products behave as oral solutions within the GI tract due to high solubility and rapid dissolution, (ii) no precipitation occurs in the GI tract once the API is dissolved, and (iii) the two IR formulations have the same in vivo dissolution profile under all intestinal”
From BCS Biowaivers: Similarities and Differences Among EMA, FDA, and WHO Requirements (2016) · cites this paper as [4]
The Biopharmaceutics Classification System (BCS) is based on aqueous solubility and intestinal permeability and has been widely used since 1995 as a mechanism for waiving in vivo bioavailability and bioequivalence studies.
“The Biopharmaceutics Classification System (BCS), based on aqueous solubility and intestinal permeability, has enjoyed wide use since 1995 as a mechanism for waiving in vivo bioavailability and bioequivalence studies.”
From BCS Biowaivers: Similarities and Differences Among EMA, FDA, and WHO Requirements (2016) · cites this paper as [4]
Cites
Diffusion, mass transfer in fluid systems
(1997) · Choice Reviews Online · doi:10.5860/choice.35-0927 · Cited by 4,931 · see citing works
Transit of pharmaceutical dosage forms through the small intestine.
Davis, S. S., Hardy, J. G., & Fara, J. W. (1986) · Gut · doi:10.1136/gut.27.8.886 · Cited by 855 · see citing works
The effect of particle size distribution on dissolution rate and oral absorption
Hintz, R. L., & Johnson, K. C. (1989) · International Journal of Pharmaceutics · doi:10.1016/0378-5173(89)90069-0 · Cited by 334 · see citing works
Amidon, G. L., Sinko, P. J., & Fleisher, D. (1988) · Pharmaceutical Research · doi:10.1023/a:1015927004752 · Cited by 300 · see citing works
Self-citationOh, D.-M., Curl, R. L., & Amidon, G. L. (1993) · Pharmaceutical Research · doi:10.1023/a:1018947113238 · Cited by 253 · see citing works
Self-citationRegional Rectal Perfusion: A New in Vivo Approach to Study Rectal Drug Absorption in Man
Lennernäs, H., Fagerholm, U., Raab, Y., Gerdin, B., & Hällgren, R. (1995) · Pharmaceutical Research · doi:10.1023/a:1016216905197 · Cited by 219 · see citing works
Self-citationOberle, R. L., & Amidon, G. L. (1987) · Journal of Pharmacokinetics and Biopharmaceutics · doi:10.1007/bf01061761 · Cited by 210 · see citing works
Self-citationRegional Jejunal Perfusion, a New in Vivo Approach to Study Oral Drug Absorption in Man
Lennernäs, H., Ahrenstedt, Ö., Hällgren, R., et al. (1992) · Pharmaceutical Research · doi:10.1023/a:1015888813741 · Cited by 203 · see citing works
Self-citationPredicting Fraction Dose Absorbed in Humans Using a Macroscopic Mass Balance Approach
Sinko, P. J., Leesman, G. D., & Amidon, G. L. (1991) · Pharmaceutical Research · doi:10.1023/a:1015892621261 · Cited by 178 · see citing works
Self-citationIn Vitro Dissolution Profile of Water-Insoluble Drug Dosage Forms in the Presence of Surfactants
Shah, V. P., Konecny, J. J., Everett, R. L., et al. (1989) · Pharmaceutical Research · doi:10.1023/a:1015909716312 · Cited by 162 · see citing works
Self-citationThe influence of the interdigestive migrating myoelectric complex on the gastric emptying of liquids
Oberle, R. L., Chen, T.-S., Lloyd, C., Barnett, J. L., Owyang, C., Meyer, J. H., & Amidon, G. L. (1990) · Gastroenterology · doi:10.1016/0016-5085(90)91150-5 · Cited by 161 · see citing works
Self-citationMixing-Tank Model for Predicting Dissolution Rate Control of Oral Absorption
Dressman, J., & Fleisher, D. (1986) · Journal of Pharmaceutical Sciences · doi:10.1002/jps.2600750202 · Cited by 156 · see citing works
The effect of L‐leucine on the absorption of levodopa, studied by regional jejunal perfusion in man.
Lennernäs, H., Nilsson, D., Sm, A., et al. (1993) · British Journal of Clinical Pharmacology · doi:10.1111/j.1365-2125.1993.tb05691.x · Cited by 117 · see citing works
Self-citationAnalysis of models for determining intestinal wall permeabilities
Amidon, G. L., Kou, J. H., Elliott, R. L., et al. (1980) · Journal of Pharmaceutical Sciences · doi:10.1002/jps.2600691204 · Cited by 106 · see citing works
Self-citationLennernäs, H., Ahrenstedt, Ö., & Ungell, A. ‐. (1994) · British Journal of Clinical Pharmacology · doi:10.1111/j.1365-2125.1994.tb04309.x · Cited by 101 · see citing works
Self-citationEffect of particle size on the bioavailability of digoxin
Jounela, A. J., Pentik�inen, P. J., & Sothmann, A. (1975) · European Journal of Clinical Pharmacology · doi:10.1007/bf00562664 · Cited by 97 · see citing works
Physicochemical Model for Dose-Dependent DrugAbsorption
Dressman, J., Fleisher, D., & Amidon, G. L. (1984) · Journal of Pharmaceutical Sciences · doi:10.1002/jps.2600730922 · Cited by 87 · see citing works
Self-citationHo, N. F. H., Merkle, H. P., & Higuchi, W. I. (1983) · Drug Development and Industrial Pharmacy · doi:10.3109/03639048309046315 · Cited by 52 · see citing works
Ni, P. (1980) · International Journal of Pharmaceutics · doi:10.1016/0378-5173(80)90048-4 · Cited by 51 · see citing works
Fagerholm, U., Borgström, L., Ahrenstedt, Ö., et al. (1995) · Journal of drug targeting · doi:10.3109/10611869509015945 · Cited by 48 · see citing works
Macheras, P. E., Koupparis, M. Α., & Antimisiaris, S. G. (1989) · Journal of Pharmaceutical Sciences · doi:10.1002/jps.2600781111 · Cited by 35 · see citing works
Sinko, P. J., Leesman, G. D., & Amidon, G. L. (1993) · Pharmaceutical Research · doi:10.1023/a:1018999130076 · Cited by 32 · see citing works
Self-citationKou, J. H., Fleisher, D., & Amidon, G. L. (1991) · Pharmaceutical Research · doi:10.1023/a:1015829128646 · Cited by 29 · see citing works
Self-citationGastrointestinal absorption of griseofulvin. II. Influence of particle size in man.
Kraml, M., DUBUC, J., & Gaudry, R. (1962) · PubMed · Cited by 23 · see citing works
Gillespie, W. R. (1991) · Pharmaceutical Research · doi:10.1023/a:1015860608173 · Cited by 6 · see citing works
Oberle, R. L. (1988) · Deep Blue (University of Michigan) · Cited by 5 · see citing works
Estimating oral drug absorption in humans.
Oh, D.-M. (1991) · Deep Blue (University of Michigan) · Cited by 4 · see citing works
Intestinal absorption characteristics of three model drugs
Lennernäs, H. (1992) · Cited by 2 · see citing works
Self-citationEstimating the dissolution and absorption of water-insoluble drugs in the small intestine.
Crison, J. R. (1993) · Deep Blue (University of Michigan) · Cited by 2 · see citing works
Self-citation
Flagged first, then by citations
Cited by
Sorted by citations
Membrane transporters in drug development
The International Transporter Consortium, Giacomini, K. M., Huang, S.-M., Tweedie, D. J., Benet, L. Z., Brouwer, K. L. R., Chu, X., Dahlin, A., Evers, R., Fischer, V., et al. (2010) · Nature Reviews Drug Discovery · doi:10.1038/nrd3028 · Cited by 3,340 · see citing works
Why 90% of clinical drug development fails and how to improve it?
Sun, D., Gao, W., Hu, H., & Zhou, S. (2022) · Acta Pharmaceutica Sinica B · doi:10.1016/j.apsb.2022.02.002 · Cited by 1,763 · see citing works
Wu, C.-Y., & Benet, L. Z. (2005) · Pharmaceutical Research · doi:10.1007/s11095-004-9004-4 · Cited by 1,401 · see citing works
Role of antioxidants in prophylaxis and therapy: A pharmaceutical perspective
Ratnam, D. V., Ankola, D. D., Bhardwaj, V., Sahana, D. K., & Kumar, M. N. V. R. (2006) · Journal of Controlled Release · doi:10.1016/j.jconrel.2006.04.015 · Cited by 885 · see citing works
Kaempferol and inflammation: from chemistry to medicine
Devi, K. P., Malar, D. S., Nabavi, S. F., Sureda, A., Xiao, J., Nabavi, S. M., & Daglia, M. (2015) · Pharmacological Research · doi:10.1016/j.phrs.2015.05.002 · Cited by 619 · see citing works
The gastrointestinal microbiota as a site for the biotransformation of drugs
Sousa, T., Paterson, R., Moore, V., Carlsson, A., Abrahamsson, B., & Basit, A. W. (2008) · International Journal of Pharmaceutics · doi:10.1016/j.ijpharm.2008.07.009 · Cited by 618 · see citing works
Charman, W. N., Porter, C. J. H., Mithani, S., & Dressman, J. B. (1997) · Journal of Pharmaceutical Sciences · doi:10.1021/js960085v · Cited by 617 · see citing works
Kell, D. B. (2009) · BMC Medical Genomics · doi:10.1186/1755-8794-2-2 · Cited by 554 · see citing works
Mudie, D. M., Murray, K., Hoad, C. L., Pritchard, S. E., Garnett, M. C., Amidon, G. L., Gowland, P. A., Spiller, R. C., Amidon, G. E., & Marciani, L. (2014) · Molecular Pharmaceutics · doi:10.1021/mp500210c · Cited by 486 · see citing works
Self-citationA review of disintegration mechanisms and measurement techniques
Markl, D., & Zeitler, J. A. (2017) · Pharmaceutical Research · doi:10.1007/s11095-017-2129-z · Cited by 439 · see citing works
Sakagami, M. (2006) · Advanced Drug Delivery Reviews · doi:10.1016/j.addr.2006.07.012 · Cited by 331 · see citing works
Predicting Clearance Mechanism in Drug Discovery: Extended Clearance Classification System (ECCS)
Varma, M. V., Steyn, S. J., Allerton, C., & El-Kattan, A. F. (2015) · Pharmaceutical Research · doi:10.1007/s11095-015-1749-4 · Cited by 334 · see citing works
Intestinal permeability and its relevance for absorption and elimination
Lennernäs, H. (2007) · Xenobiotica · doi:10.1080/00498250701704819 · Cited by 304 · see citing works
Self-citationYáñez, J. A., Remsberg, C. M., Sayre, C. L., Forrest, M. L., & Davies, N. M. (2011) · Therapeutic Delivery · doi:10.4155/tde.11.19 · Cited by 279 · see citing works
Dahan, A., Miller, J. M., Hoffman, A., Amidon, G. E., & Amidon, G. L. (2010) · Journal of Pharmaceutical Sciences · doi:10.1002/jps.22033 · Cited by 224 · see citing works
Self-citationReview and analysis of FDA approved drugs using lipid-based formulations
Savla, R., Browne, J., Plassat, V., Wasan, K. M., & Wasan, E. K. (2017) · Drug Development and Industrial Pharmacy · doi:10.1080/03639045.2017.1342654 · Cited by 225 · see citing works
Miller, J. M., Beig, A., Krieg, B. J., Carr, R. A., Borchardt, T. B., Amidon, G. E., Amidon, G. L., & Dahan, A. (2011) · Molecular Pharmaceutics · doi:10.1021/mp200181v · Cited by 204 · see citing works
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Desai, P. P., Date, A. A., & Patravale, V. B. (2012) · Drug Discovery Today: Technologies · doi:10.1016/j.ddtec.2011.12.001 · Cited by 199 · see citing works
Fahr, A., Hoogevest, P. V., May, S., Bergstrand, N., & S. Leigh, M. L. (2005) · European Journal of Pharmaceutical Sciences · doi:10.1016/j.ejps.2005.05.012 · Cited by 189 · see citing works
Johannsson, G., Bergthorsdottir, R., Nilsson, A. G., Lennernas, H., Hedner, T., & Skrtic, S. (2009) · European Journal of Endocrinology · doi:10.1530/eje-09-0170 · Cited by 173 · see citing works
Sjögren, E., Westergren, J., Grant, I., Hanisch, G., Lindfors, L., Lennernäs, H., Abrahamsson, B., & Tannergren, C. (2013) · European Journal of Pharmaceutical Sciences · doi:10.1016/j.ejps.2013.05.019 · Cited by 168 · see citing works
Self-citationRozehnal, V., Nakai, D., Hoepner, U., Fischer, T., Kamiyama, E., Takahashi, M., Yasuda, S., & Mueller, J. (2012) · European Journal of Pharmaceutical Sciences · doi:10.1016/j.ejps.2012.02.025 · Cited by 156 · see citing works
Shah, V. P., & Amidon, G. L. (2014) · The AAPS Journal · doi:10.1208/s12248-014-9620-9 · Cited by 150 · see citing works
Self-citationMiller, N. A., Reddy, M. B., Heikkinen, A. T., Lukacova, V., & Parrott, N. (2019) · Clinical Pharmacokinetics · doi:10.1007/s40262-019-00741-9 · Cited by 142 · see citing works
TANNERGREN, C. (2004) · Clinical Pharmacology & Therapeutics · doi:10.1016/j.clpt.2003.12.012 · Cited by 138 · see citing works
Behrens, I., & Kissel, T. (2003) · European Journal of Pharmaceutical Sciences · doi:10.1016/s0928-0987(03)00146-5 · Cited by 117 · see citing works
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Lennernäs, H. (2014) · European Journal of Pharmaceutical Sciences · doi:10.1016/j.ejps.2013.08.025 · Cited by 103 · see citing works
Self-citationAmann, L. C., Gandal, M. J., Lin, R., Liang, Y., & Siegel, S. J. (2010) · Pharmaceutical Research · doi:10.1007/s11095-010-0152-4 · Cited by 99 · see citing works
Calvarysky, B., Dotan, I., Shepshelovich, D., Leader, A., & Cohen, T. D. (2024) · Drug Safety · doi:10.1007/s40264-023-01392-3 · Cited by 97 · see citing works
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Davit, B. M., Kanfer, I., Tsang, Y. C., & Cardot, J.-M. (2016) · The AAPS Journal · doi:10.1208/s12248-016-9877-2 · Cited by 92 · see citing works
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Chen, M.-L., Amidon, G. L., Benet, L. Z., Lennernas, H., & Yu, L. X. (2011) · Pharmaceutical Research · doi:10.1007/s11095-011-0438-1 · Cited by 93 · see citing works
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Hausner, H., Derving Karsbøl, J., Holst, A. G., Jacobsen, J. B., Wagner, F.-D., Golor, G., & Anderson, T. W. (2017) · Clinical Pharmacokinetics · doi:10.1007/s40262-017-0532-6 · Cited by 62 · see citing works
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Michaelsen, M. H., Wasan, K. M., Sivak, O., Müllertz, A., & Rades, T. (2016) · The AAPS Journal · doi:10.1208/s12248-015-9832-7 · Cited by 55 · see citing works
Siqueira Jørgensen, S. D., Al Sawaf, M., Graeser, K., Mu, H., Müllertz, A., & Rades, T. (2018) · European Journal of Pharmaceutics and Biopharmaceutics · doi:10.1016/j.ejpb.2017.12.014 · Cited by 51 · see citing works
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Malm-Erjefält, M., Ekblom, M., Vouis, J., Zdravkovic, M., & Lennernäs, H. (2015) · Molecular Pharmaceutics · doi:10.1021/acs.molpharmaceut.5b00278 · Cited by 36 · see citing works
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Self-citationMendes, C., Buttchevitz, A., Kruger, J. H., Kratz, J. M., Simões, C. M. O., de Oliveira Benedet, P., Oliveira, P. R., & Silva, M. A. S. (2016) · European Journal of Pharmaceutical Sciences · doi:10.1016/j.ejps.2015.12.015 · Cited by 31 · see citing works
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Self-citationCook, J. (2015) · Dissolution Technologies · doi:10.14227/dt220215p6 · Cited by 8 · see citing works
- Authors
- Amidon, G. L., Lennernäs, H., Shah, V. P., & Crison, J. R.
- Affiliations
- University of Michigan (US)
- Uppsala University (SE)
- United States Food and Drug Administration (US)
- Therapeutics Systems Research Laboratories (United States) (US)
- Venue
- Pharmaceutical Research
- Published
- 1995-03
- Volume
- 12
- Issue
- 3
- Pages
- 413-420
- ISSN
- 0724-8741 (ISSN-L)
- 1573-904X
- OpenAlex
- W1498305210
- Cited by
- 5,430
- References
- 29
- Citations by year
- 2026: 170 · 2025: 201 · 2024: 182 · 2023: 240 · 2022: 266 · 2021: 282 · 2020: 299 · 2019: 241 · 2018: 278 · 2017: 267 · 2016: 283 · 2015: 283 · 2014: 302 · 2013: 296 · 2012: 302
- FWCI
- 26.02
- Type
- journal article
- Language
- en
- Open access
- closed
- Licence
- Locations
- Pharmaceutical Research (publishedVersion)
- PubMed (publishedVersion)
- Deep Blue (University of Michigan) (submittedVersion)
- Funders
- U.S. Food and Drug Administration (FD-01462)
- National Institute of General Medical Sciences (GM 37188, R01GM037188)
- Topics
- Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Pharmaceutical Science › Drug Solubulity and Delivery Systems
- Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Pharmaceutical Science › Advanced Drug Delivery Systems
- Health Sciences › Medicine › Pediatrics, Perinatology and Child Health › Pharmaceutical studies and practices
- Keywords
- in vitro-in vivo correlation, drug dissolution, bioavailability, gastrointestinal permeability, oral drug absorption, solubility, transport modeling, dissolution profile, surfactants
- MeSH terms
- Biological Availability, Cimetidine, Pharmaceutical Preparations, Gastric Emptying, Jejunum, Mathematics, Models, Theoretical, Permeability, Piroxicam, Solubility, In Vitro Techniques
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