Effect of hydrophilic and hydrophobic polymer on the release of ketoprofen and allopurinol from bilayer matrix transdermal patch

The aim of this study was to design a matrix transdermal patch of ketoprofen and allopurinol for the possible treatment of arthritis with reduced side effects. For this purpose, a bilayer matrix transdermal patch was prepared with an immediate release layer of Methocel containing ketoprofen while secondary sustained layer composed of allopurinol with combinations of Eudragit RL100 and Methocel. The patch was studied for swelling index in distilled water and was found to increase with an increase in concentration of hydrophilic polymer. The in vitro dissolution was conducted in USP dissolution apparatus II using phosphate buffer saline (pH 7.4) as dissolution medium at 37 +/- 2 degrees C. Based on in vitro dissolution studies, KA1(BL) (99.65% release in 10 hr) was selected for ex vivo permeation studies through Franz diffusion cell using excised abdominal skin of albino rats, and using clove oil and menthol as permeation enhancers. The optimized formulation KA1(BL)-M-3 released 69.37% drug over 12 hr and followed zero-order kinetics with anomalous release mechanism. The patch had uniform distribution of components as per digital microscopic analysis.