Development of matrix controlled transdermal delivery systems of pentazocine: In vitro/in vivo performance

The present study aimed to develop hydroxypropyl methylcellulose based transdermal delivery of pentazocine. In formulations containing lower proportions of polymer, the drug released followed the Higuchi kinetics while, with an increase in polymer content, it followed the zero-order release kinetics. Release exponent (n) values imply that the release of pentazocine from matrices was non-Fickian. FT-IR, DSC and XRD studies indicated no interaction between drug and polymer. The in vitro dissolution rate constant, dissolution half-life and pharmacokinetic parameters (C(max), t(max), AUC((s)), t(1/2), K(el), and MRT) were evaluated statistically by two-way ANOVA. A significant difference was observed between but not within the tested products. Statistically, a good correlation was found between per cent of drug absorbed from patches vs. C(max) and AUC((s)). A good correlation was also observed when per cent drug released was correlated with the blood drug concentration obtained at the same time point. The results of this study indicate that the polymeric matrix films of pentazocine hold potential for transdermal drug delivery.