Theoretical Model Studies of Drug Absorption and Transport in the Gastrointestinal Tract I
TL;DR: The pH-partition theory is shown to be a limiting case of the more general approach presented, and increasing the agitation rate in the aqueous phase markedly affects the pH profiles for the rate of transport.
About: This article is published in Journal of Pharmaceutical Sciences.The article was published on 1970-05-01. It has received 112 citations till now. The article focuses on the topics: Diffusion layer & Aqueous solution.
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TL;DR: The application of a gastrointestinal simulation for the prediction of oral drug absorption and bioavailability will be described and the simulated impact of physiological and biochemical processes on oral drug bioavailability is illustrated.
578 citations
TL;DR: This review focuses on the dynamic models, which predict both the fraction of dose absorbed and the rate of drug absorption and can be related to pharmacokinetic models to evaluate plasma concentration profiles.
322 citations
TL;DR: The absorption of drugs via the oral route is a subject of intense and continuous investigation in the pharmaceutical industry since good bioavailability implies that the drug is able to reach the systemic circulation by mouth.
Abstract: The absorption of drugs via the oral route is a subject of intense and continuous investigation in the pharmaceutical industry since good bioavailability implies that the drug is able to reach the systemic circulation by mouth. Oral dry absorption is affected by both drug properties and the
252 citations
212 citations
27 May 2003
TL;DR: This book discusses comparative approaches to drug Absorption and Bioavailability, and the role of transport and metabolism in ORAL ABSORPTION, and applications of the Biopharmaceutical Classification System Now and in the Future.
Abstract: Preface.Foreword.List of Authors.I. STUDIES OF MEMBRANE PERMEABILITY AND ORAL ABSORPTION.1. Physico-chemical Approaches to Drug Absorption (H. van de Waterbeemd).2. High-throughput Measurement of log D and pKa (J. Comer).3. High-throughput Measurement of Permeability Profiles (A. Avdeef).4. Caco-2 and Emerging Alternatives for Prediction of Intestinal Drug Transport: A General Overview (P. Artursson & S. Tavelin).5. Cell Cultures in Drug Discovery: An Industrial Perspective (A. Ungell & J. Karlsson).6. Use of Animals for the Determination of Absorption and Bioavailability (C. Logan).7. In Vivo Permeability Studies in the Gastrointestinal Tract of Humans (N. Petri & H. Lennernas).II. DRUG DISSOLUTION AND SOLUBILITY.8. Gastrointestinal Dissolution and Absorption of Drugs (G. Granero, et al.).9. Aqueous Solubility in Discovery, Chemistry, and Assay Changes (C. Lipinski).10. Factors Influencing the Water Solubilities of Crystalline Drugs (J. McFarland, et al.).III. ROLE OF TRANSPORTERS AND METABOLISM IN ORAL ABSORPTION.11. Transporters in the GI Tract (H. Shin, et al.).12. Hepatic Transport (H. Suzuki & Y. Sugiyama).13. The Importance of Gut Wall Metabolism in Determining Drug Bioavailability (K. Beaumont).14. Modified Cell Lines (C. Crespi).IV. COMPUTATIONAL APPROACHES TO DRUG ABSORPTION AND BIOAVAILABILITY.15. Intestinal Absorption: The Role of Polar Surface Area (P. Artursson & C. Bergstrom).16. Calculated Molecular Properties and Multivariate Statistical Analysis in Absorption Prediction (U. Norinder & M. Haeberlein).17. VOLSURF: A Tool for Drug ADME-properties Prediction (G. Cruciani, et al.).18. Simulation of Absorption, Metabolism, and Bioavailability (M. Bolger, et al.).19. Prediction of Bioavailability (A. Mandagere & B. Jones).20. Towards P-Glycoprotein Structure-Activity Relationships (A. Seelig, et al.).V. DRUG DEVELOPMENT ISSUES.21. Application of the Biopharmaceutical Classification System Now and in the Future (B. Abrahamsson & H. Lennernas).22. Prodrugs (B. Steffansen, et al.).23. Modern Delivery Strategies: Physiological Considerations for Orally Administered Medications (C. Wilson).Index.
194 citations
References
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Book•
01 Jan 1966
TL;DR: In this article, the Straight Line Case is used to fit a straight line by least squares, and the Durbin-Watson Test is used for checking the straight line fit.
Abstract: Basic Prerequisite Knowledge. Fitting a Straight Line by Least Squares. Checking the Straight Line Fit. Fitting Straight Lines: Special Topics. Regression in Matrix Terms: Straight Line Case. The General Regression Situation. Extra Sums of Squares and Tests for Several Parameters Being Zero. Serial Correlation in the Residuals and the Durbin--Watson Test. More of Checking Fitted Models. Multiple Regression: Special Topics. Bias in Regression Estimates, and Expected Values of Mean Squares and Sums of Squares. On Worthwhile Regressions, Big F's, and R 2 . Models Containing Functions of the Predictors, Including Polynomial Models. Transformation of the Response Variable. "Dummy" Variables. Selecting the "Best" Regression Equation. Ill--Conditioning in Regression Data. Ridge Regression. Generalized Linear Models (GLIM). Mixture Ingredients as Predictor Variables. The Geometry of Least Squares. More Geometry of Least Squares. Orthogonal Polynomials and Summary Data. Multiple Regression Applied to Analysis of Variance Problems. An Introduction to Nonlinear Estimation. Robust Regression. Resampling Procedures (Bootstrapping). Bibliography. True/False Questions. Answers to Exercises. Tables. Indexes.
18,952 citations
Book•
01 Jan 1960
TL;DR: This is the book that many people in the world waiting for to publish, mathematical methods for digital computers, and the book lovers are really curious to see how this book is actually.
Abstract: Now welcome, the most inspiring book today from a very professional writer in the world, mathematical methods for digital computers. This is the book that many people in the world waiting for to publish. After the announced of this book, the book lovers are really curious to see how this book is actually. Are you one of them? That's very proper. You may not be regret now to seek for this book to read.
1,056 citations
Journal Article•
TL;DR: The pattern of drug secretion can be explained by the concept that the membrane separating plasma from gastric juice has the characteristics of a lipoid membrane that allows the passage of drugs in their undissociated form while restricting passage of dissociated form.
Abstract: Parenterally administered drugs are secreted directly into the gastric juice. The concentration ratio (concentration of drug in gastric juice divided by concentration in plasma) depends on the dissociation constant of the drug. Thus strong acids appear in gastric juice in negligible concentration, weak acids and weak bases in measurable amount and stronger bases in highest concentration. The stronger bases appear in a limiting concentration ratio of about 40 to 1 when gastric juice flow is maximal, the limitation apparently being due to complete clearance by the gastric mucosa. The pattern of drug secretion can be explained by the concept that the membrane separating plasma from gastric juice has the characteristics of a lipoid membrane that allows the passage of drugs in their undissociated form while restricting passage of dissociated form.
468 citations
TL;DR: In this paper, a number of theoretical relations dealing with diffusion through heterogeneous barriers are presented and discussed, which are expected to be useful in predicting barrier behavior in formulations such as pharmaceutical and particularly protective ointments and films.
Abstract: A number of theoretical relations dealing with diffusion through heterogeneous barriers are presented and discussed. These are expected to be useful in predicting barrier behavior in formulations such as pharmaceutical and particularly protective ointments and films. A relationship has been derived which expresses the effective permeability constant, Pm, of a two phase mixture as a function of the volume fraction and the permeability of each phase. The effect of the shape of the particles on Pm is also considered. Where data are available, agreement with theory is satisfactory. The nonstationary state behavior of a two phase heterogeneous barrier is discussed in relation to the diffusion coefficient, partition coefficient, the volume fraction, and the particle size associated with each phase. It is shown that the effectiveness of one heterogeneous barrier may be greater than another for a given time of exposure while for a longer time of exposure the reverse may be the case. The effect of a “skin” or a coat of a third phase on the internal phase particle has also been examined. Finally, the situation in which simultaneous diffusion and absorption occur is discussed and an expression for the lag time has been derived for this case.
147 citations