Development and evaluation of chitosan based oral controlled matrix tablets of losartan potassium

Aim and Background: The novelty of the present study was to control the release profile of matrix tablets of losartan potassium prepared by using different concentrations of chitosan and trisodium citrate as cross-linking agent with combination of various release retardant polymers. Materials and Methods: Twelve formulations were prepared using HPMC K100M, carbopol 934P, and xanthan gum as polymers. Matrix tablets were prepared by wet granulation technique. The granules were subjected to precompression parameters such as angle of repose, loose bulk density, tapped bulk density, compressibility index. Tablets were evaluated for weight variation, hardness, drug content, in-vitro dissolution, stability studies, respectively. Drug -polymer compatibility studies were determined by FTIR spectroscopy. Further stability studies were carried out for 3months in accelerated conditions at 40ºC and 75%RH. The granules of all formulations exhibited good flow and compressibility. In-vitro dissolution studies were carried out for 24 h using 0.1 N HCl for the first 2 h and pH 6.8 phosphate buffers for the remaining 22h. Results: It was found that among the 12 formulations F11 and F12 showed good dissolution profile to control the drug release. The release data was fitted to various mathematical models such as, Higuchi, Korsmeyer, first-order, and zero-order to evaluate the kinetics and the drug release. The drug release follows zero-order kinetics and the mechanism was found to be diffusion controlled and Case II transport. FT-IR spectroscopic studies revealed no interaction between drug and polymer. The stability studies indicated that F11 and F12 formulations were stable for 3months. Conclusion: The above results concluded that by combining different classes of polymers an acceptable release profile can be obtained in the fluctuating in vivo environment.