Development and Evaluation of a Novel Oro-Sustained Stomach Specific Floating in Situ Gelling System of Azithromycin Dihydrate

Floating drug delivery system provides the advantage of sustained release of drugs over a prolonged period of time thereby maximising the oral absorption of drugs with narrow absorption window, thus, it overcomes the drawback of conventional oral drug delivery system. In situ gelling system is a novel approach in this regard. The aim of the present work was to develop an oral sustained stomach specific novel floating in situ gelling system of Azithromycin dihydrate. In situ gelling system were prepared by dissolving different concentrations of gelling polymers like sodium alginate, xanthan and combination of sodium alginate and xanthan gum in deionized water at 80 0 C. After cooling to 40 0 C fixed amount of drug and calcium carbonate were dispersed in it with continuous stirring. Compatibility between drug and polymers were confirmed by FTIR studies. All formulations showed pH in the range of 6.5 to 6.9, drug content was found to be in the range of 97.92% to 99.27%, floating lag time was less than 1 min, duration of floating was more than 24 h for all the prepared formulations. Gelling capacity, viscosity and water uptake by the gel increased with the increase in polymer concentration. In vitro drug release was found to be in between 68.81% to 89.49%, up to 8 h with formulation F1 showing the maximum drug release. Combination polymers showed better sustained release of drug over a period of 8h. Drug release was found to decrease with the increase in polymer concentration and water uptake by gel. The release kinetics of all the formulations followed Higuchi diffusion mechanism. Hence, an oral sustained stomach specific floating in situ gelling system of Azithromycin dihydrate could be prepared using different concentrations of combination polymers to increase the patient compliance with reduced dosing frequency and increased residence time of drug in the stomach.