SYSTEM DESIGN AND CHARECTERIZATION OF TRANDERMAL FILMS OF FELODIPINEAuthor(s): JIJI JOSE , R. NARAYANACHARYULU and MOLLY MATHEW
The present investigation was taken up to prepare and evaluate a transdermal drug delivery system of felodipine to increase its bioavailability. The matrix type patches were prepared using the polymer blend of eudragit RL 100 (ERL)/RS 100 (ERS) by solvent casting method and to study the effect of polymer composition, plasticizer and permeation enhancer on the physico-mechanical and in vitro drug release characteristics of the film. Polyethylene glycol 400 (PEG400) and glycerin were used as plasticizer and permeation enhancer, respectively. Incorporation of PEG 400 improved the flexibility, folding endurance and handling properties of the films. Increasing the concentration of ERL and the presence of plasticizer were found to increase the in vitro drug release of the films. The patches were also evaluated for ex vivo skin permeation using human cadaver skin. The presence of glycerin produced significant increase in the flux and permeability constant. The formulation with ERL : ERS ratio 4 : 1, 5% w/w glycerin as permeation enhancer and 10% w/w PEG 400 as plasticizer showed the best results, which exhibited the cumulative percentage of drug release of 63.57% and the cumulative amount of drug permeation across skin of 3557.2 µg/cm2 in 24 hrs. Drug-excipient interaction studies were carried out using DSC and IR technique; films indicated no chemical interaction between drug and excipient. The results of the skin irritation studies showed no noticeable irritancy on rabbit skin indicating the skin compatibility of the drug as well as polymer. An attempt was made to develop the complete transdermal system of the drug by using backing membrane and release liner.