Abstract
Most of the floating systems have inherent drawbacks of high variability in the gastro intestinal transit time, invariably affecting the bioavailability of drug. To overcome it, a multiple unit floating system with extended GI transit time, capable of distributing widely throughout the gastrointestinal tract for effective enteric release of the drug has sought. Microballoons loaded with drug in their outer polymer shells were prepared by novel emulsion solvent diffusion method. The ethanol: dichloromethane solution of drug and polymers (HPMC, Eudragit S100, Carbapol 934) each with a ratio of 1:1, 1:2 and 1:3 respectively were poured into the solution of heavy liquid paraffin containing 1.5% span 80. The flowability of resulting microballoons improved when compared to that of the pure drug. The formulations were evaluated for percentage practical yield, particle size analysis, percentage drug loading, drug entrapment efficiency, floating behavior, Scanning Electron Micrography, FTIR, DSC, dissolution study and the drug release kinetics. The enhanced floatability of the formulations and their retention in GIT may attribute for the increased bioavailability and decrease in frequency of administration. Of all the three polymers used it was observed that HPMC to be a suitable candidate for sustained release of the drug from that of the floating microspheres (microballoons). Among the three formulations prepared with HPMC, formulation F1 (drug: polymer 1:1) was found to be an optimized one with particle size of 32.96µm, 40.46% drug entrapment efficiency, 91.03 percentage yield, 69.88% buoyancy and 20.74% of drug loading. At the end of 12th hr the drug release rate was found to be 96.42%.
