Design of Floating Tablets Based on Hydroxypropyl Cellulose and Weakly Cross-Linked Poly(acrylic acid) for Gastroretentive Drug Delivery

Abstract

Floating or buoyant dosage forms are kind of gastroretentive delivery system specifically designed to achieve localized drug release in the upper gastrointestinal tract (GI). The aim of this study is to select a composition for creating a floating matrix system based on hydroxypropyl cellulose (HPC) and Carbopol® 71G (C71G) with an evaluating of the effect of sodium bicarbonate (Na-bicarbonate) on the complexation process, and to design a gastroretentive system for acyclovir delivering. The tablets are based on physical mixtures (PhMs) HPC/C71G 1:2; 1:1. All matrices containing sodium bicarbonate showed a flotation time of less than 3 minutes, with the exception of a 2:1 PhM with 10 mg of sodium bicarbonate. PhM HPC/C71G (1:1) was observed greater matrix erosion compared to a 1:2 ratio due to the lower C71G content. During the swelling process of the matrices, interaction of polymers occurs, which is confirmed by a spectral shift in the ATRFTIR spectra and Tg by mDSC. The addition of sodium bicarbonate did not increase the release rate due to the effervescent effect. A slightly higher release rate was observed for matrices with a 1:1 polymer ratio, due to erosion of the soluble HPC polymer.