Preparation of transdermal monolithic systems of indapamide by solvent casting method and the use of vegetable oils as permeation enhancer G.

Abstract

Transdermal drug delivery systems of indapamide have been formulated by using solvent casting method. Monolithic systems were prepared by using hydroxy propyl methyl cellulose (HPMC) and ethyl cellulose (EC) polymers by incorporating glycerine and dibutyl phthalate as plasticizers, respectively. All the patches were uniform with respect to physicochemical and scanning electron microscopy (SEM) evaluation. Th e in vitro drug release studies indicated that HPMC containing fi lms have shown better release than that of EC containing fi lms without any permeation enhancer. A total of eight monolithic systems were prepared by using a drug polymer ratio of 1:4 and incorporated diff erent vegetable oils as permeation enhancers in diff erent concentrations. Th e prepared systems released the drug in the following order: F3 > F4 > F7 > F5 > F8 > F6 > F1 > F2. Th e various permeation parameters such as fl ux, permeability coeffi cient, enhancement ratio and diff usion rate constants were determined for all the formulations. Th e maximum fl ux of 9.08 × 102 mg/ cm2 h was observed with HPMC monolithic system containing 30% w/w olive oil. A signifi cant improvement of fl ux was observed in the following order: olive oil > linseed oil > sunfl ower oil > cottonseed oil > coconut oil > castor oil. Further improvement of fl ux was observed, when 30% w/w olive oil was applied directly onto the skin prior to the studies. Th e in vitro release studies revealed that the release was sustained up to 24 h and it follows zero-order kinetics. All the fi lms were found to be stable at 37°C and 45°C with respect to their physical parameters and drug content. Key words: EC, HPMC, linseed oil, olive oil, permeation enhancers, sunfl ower oil, transdermal