Sustained-release dosage form of nicardipine hydrochloride: Application of factorial design and effect of surfactant on release kinetics

Microcapsules of nicardipine hydrochloride with core:wall ratios of 1:1, 2:1, and 1:2 were prepared by the coacervation-phase separation method, using ethylcellulose as the coating material. Two batches of nicardipine hydrochloride microscapsules were divided into size fraction by using standard sieves ranging from 840 mu m to 476 mu m. Dissolution rate studies from microcapsules were performed using the USP XXII basket method. The kinetic model according to the Rosin-Rammler-Sperling-Bennet-Weibull (RRSBW) distribution was applied for the parametric representation of the dissolution curves. Preparation and dissolution rate studies on the nicardipine hydrochloride microcapsules were performed and the influence of particle size, core:wall ratio, and the amount of nicardipine hydrochloride on the release rate was examined by 2(3) factorial design. The significance of the observed effects was tested with the F test. A surface active substance was added in the dissolution medium to understand how this substance effects the release of drug from ideal microcapsule form which is found by the findings of the 2(3) factorial design. Dissolution studies were repeated with this ideal formulation using different ratio of Tween 20. The results of this study suggested that the solubility and bioavailability of the sustained-release dosage forms of nicardipine hydrochloride using surface active substances could be increased.