Drug absorption gastric emptying

GD Leesman, PJ Sinko, GL Amidon. Simulation of oral drug absorption Gastric emptying and gastrointestinal motility. In PG Welling, FLS Tse, eds. Pharmacokinetics. 2nd ed. New York Marcel Dekker, 1989, pp 267-284. 

As discussed previously, drug absorption may be impaired or improved when food is present in the GIT. Food may reduce the rate or extent of absorption by virtue of reduced gastric-emptying rate, which is particularly important for compounds unstable in gastric fluids and for dosage forms designed to release drug... 

P. Langguth, K. M. Lee, H. Spahn-Langguth, G. L. Amidon. Variable gastric emptying and discontinuities in drug absorption profiles dependence of rates and extent of cimeti-dine absorption on motility phase and pH. Biopharm. Drug Disposit. 1994,... 

The absorption of class III drugs is limited by their permeability over the intestinal wall. Thus, as this process is not at all modeled by the classical in vitro dissolution test, no IVIVC should be expected. When drug dissolution becomes slower than gastric emptying, a reduction in the extent of bioavailability will be found in slower dissolution rates as the time when the drug is available for permeation over the gut wall in the small intestine will then be reduced. Thus, the same type of relationship can be expected between bioavailability and in vitro dissolution, as shown in Fig. 21.12 for a class I drug. 

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