In vitro and in vivo assessment of matrix type transdermal therapeutic system of labetalol hydrochloride.

Objective: The aim of the investigation was to develop and evaluate matrix type transdermal therapeutic systems containing new polymeric combinations (Eudragit E PO/Eudragit RL 100 & Plasdone S 630) as polymers and Labetalol Hydrochloride (LBHCl) as a model drug.

Methods: The matrix type TTS of LBHCl were prepared by film casting technique. The patches were characterized for physical, in vitro release studies & ex-vivo permeation studies (human cadaver skin). On the basis of in vitro drug release and skin permeation performance, formulation A1 was found to be better than the other formulations and it was selected as the optimized formulation. The optimized patch was assessed for its pharmacokinetic, pharmacodynamic, skin irritation potential, and stability studies.

Results: The maximum percentage drug release & Permeation in 48 hrs were 92.43 % and 76.24 % respectively for optimized patch. The Korsmeyer peppas release exponent value of 0.604 suggested release mechanism towards first order release in the optimized formulation. The results obtained from the in vivo characterization of the optimized patch showed sustained action of the developed formulation. The interaction studies analysis indicated no chemical interaction between the drug and polymers. The optimized patch was seemingly free of potentially hazardous skin irritation as suggested by skin irritation score of 0.915<2.00 (under Draize score test). The optimized formulation was found to be stable at ambient storage conditions.

Conclusions: The above TTS holds promise for improved bioavailability and better management of hypertension on long term basis.