Design and characterization of orlistat bilayered controlled release tablets

Drug delivery in conventional dosage forms often suffers from the drawbacks of repeated drug administration and large fluctuations in blood drug levels. Controlled drug delivery systems are a convenient way of controlling the dosing frequency responsible for rapid absorption and distribution of drug in conventional dosage forms, and are dependent upon two intrinsic properties of the drug, namely, elimination half-life (ti/2) and therapeutic index (TI). The goal is to give a drug at a sufficient rate, frequency and dose so that the ratio Cmax/Cmin in plasma at steady state is always maintained at effective concentrations during the course of therapy, reducing side effects or improving physicochemical and biopharmaceutical properties. The use of polymers provides the potential to control drug delivery both temporally and spatially. The objective of the present investigation was to develop bilayered tablets of orlistat to achieve controlled release and immediate release. The process is predetermined in such a way to release the drug at an IR and CR by using different polymers. Half life of orlistat is 1–2 hrs, as it has been released immediately. This paper mainly focuses on designing the process to release the drug in a controlled manner by using different polymers like sodium alginate, ethyl cellulose, HPMC.