Abstract

Polymers have become an indispensable part in the design of a conventional as well as novel drug delivery system. Gum Copal (GC), a novel biomaterial obtained from Agathis species, is evaluated in the present study for its potential application as a matrix former in transdermal drug delivery systems. GC was initially characterized for various physicochemical properties and then mechanical characterization of the Plasticized films of GC was investigated. Verapamil hydrochloride (VH), owing to its pharmacokinetic properties, was selected as the model drug for the present work. Matrix type transdermal films of VH with GC, alone and in combination with polyvinyl pyrrolidone (PVP K-30), were developed and evaluated for various physicochemical properties. In-vitro drug release study was carried out using paddle over disk method and in-vitro skin permeation study was performed using human cadaver skin. On the basis of physicochemical properties, in-vitro drug release study and permeation performance, formulation F5 containing GC: PVP K-30 (60:40) was selected as an optimized formulation for in vivo study. Animal studies were carried out using Dawley rats and the data obtained from the plasma drug analysis showed that peak drug concentration of about 244.94 ± 1.25 ng/mL was achieved in 6 h after the application of the patch and plasma drug concentration was maintained till 24 h. Skin irritancy test results proved the suitability of the biomaterial for transdermal application. The drug polymer interaction studies carried out using UV, FTIR and TLC analysis indicated that drug and polymer were compatible. Due to reasonably good mechanical properties, low water vapor transmission and sustained release capability, GC seems to be a promising film former for transdermal drug delivery.

Keywords: Verapamil hydrochloride, matrix system, in vitro release, in vitro permeation, transdermal drug delivery, Gum Copal, skin irritancy, plasma analysis, folding endurance, water vapor transmission, acid value, saponification value, drug-carrier interaction