Gastroretentive drug delivery system An overview

Abstract

The density of a dosage form affects the gastric emptying rate and determines the location of the system in the stomach. Dosage forms which are having density lower than the gastric contents can float to the surface, while high-density systems sink to bottom of the stomach. [7] Both the positions may isolate the dosage system from the pylorus part of the stomach. A density of <1.0 g/cm 3 is required to show floating property. [8] Streubel et al. prepared the single-unit floating tablets based on polypropylene [9] foam powder and matrix-forming polymer and the incorporation of highly porous foam powder in matrix tablets provided density much lower than the density of the release medium. A 17% wt/wt foam powder (based on the mass of tablet) showed in vitro release for at least 8 h. It was thus concluded that varying the ratios of matrix-forming polymers and the foam powder could alter the drug release patterns effectively. The Chitosan-Carbopol 940 mixed matrices that were used to modify release rates in hydrophilic matrix tablets prepared by direct compression, and incorporation of the highly porous low-density copolymer and poly(styrene-divinylbenzene) Copolymer in the matrix tablets provides densities that were lower than the density of the release medium and 17% w/w low-density copolymer (based on the mass of the tablet) was sufficient to achieve proper in vitro floating behavior for at least 8 h. [10]