Release kinetics of a controlled-release multiparticulate dosage form prepared using a hot-melt fluid bed coating method

Dissolution profiles of various multiparticulate controlled-release dosage forms prepared by applying lipophilic materials using a hot-melt coating technique were analyzed to determine release kinetics. The dosage forms were prepared using a novel solid dispersion hot-melt fluid bed coating method. Various lipophilic materials were investigated and those showing promise as potential controlled-release coating agents were analyzed further. Dissolution data were used as the primary basis of comparison. A dual equation combining first-order and square-root-of-time release kinetics was used to fit data. The statistical output from nonlinear regression software suggests that this equation describes the data better than the individual equations alone. Particular parameters used to compare the various models include R-2, the model selection criteria, and the coefficient of determination. The high degree of fit offered by the dual equation implies that two distinct kinetic processes may be involved in the release of drug from the dosage forms. A possible release mechanism based on this information is offered The dual equation was shown to be a superior model for the controlled-release system chosen for study. The equation also appears to be applicable to a variety of other controlled release systems reported in the literature.