Floating minitablets loaded with captopril encapsulated microparticles

Abstract

The objectives of current work were to develop chitosan microparticles loaded controlled release floating gas generating minitablets of captopril. Chitosan microparticles were developed using ionic gelation method by dropping sodium tripolyphosphate solution into chitosan solution under stirring. Primary formulation variables were screened by applying Plackett Burman design and levels of most significant risk factors were optimized using 32 factorial design. Primary formulation variables were chitosan concentration (X1), sodium tripolyphosphate concentration (X2) and speed of stirring. Optimized batch of microparticle has particle size of 346.9 nm, zeta potential of 9.16 mv and drug release of 96% in simulated gastric fluid at the end of 8 h. Further microparticle loaded minitablets were developed and optimized. Microparticle loaded minitablets are characterized for parameters like dissolution, floating lag time, total floating time etc. Stability study of the optimized batch was carried out at 40 ᵒC/75% RH for 6 months and at 30 ᵒC/5% RH for 1 year. In vivo behaviour of optimized tablets was studied in rabbits with the help of X-ray studies. Optimized formulations were retained and floating in the gastric region for more than 24hrs. Bioavailability study confirms prolonged drug release.