CONVOLUTION STUDY AND THE ALCOHOLIC BEVERAGE EFFECT ON LANSOPRAZOLE DELAYED-RELEASE CAPSULES AND APPLICATION OF SIMILARITY FACTOR TO TWO-STAGE IN – VITRO DISSOLUTION PARADIGM

Lansoprazole, a proton pump inhibitor, is used to treat ulcers in the stomach and duodenum. In order to protect this acid labile drug from being degraded in the gastric medium, the marketed oral dosage forms are formulated into delayed release pellets and tablets. The aims of this research were (1) to investigate the principal site of drug release and absorption rate between an over-the-counter (OTC) product and a prescription brand, and (2) to explore the effect of ethanol on the in vitro release profile of the OTC product. For aim No. 1, the in vitro release profile conducted in our lab was convoluted with the lansoprazole plasma concentration time profile of an intravenous bolus reported by Gerloff, et al. For aim No. 2, the dissolution of OTC capsules was studied with 250 mL of 0.1 N HCl combined with equal volume of laboratory simulated beer and wine, which contained 5 and 11.5 % alcohol respectively to compare to its reference, 0% (n=6). Furthermore, the dissolution of the OTC formulation in the simulated alcoholic beverage showed no difference between 5 %, 11.5 % and 0 % ethyl alcohol (n=8, U.S. FDA similarity factor, f₂ > 50). We further explore the explanation why in spite that the biological half-life of lansoprazole is only 1.1 h, the over the counter products are designed to dose once daily