Design of optimized diffusion-controlled transdermal drug delivery systems

Abstract

Background: We describe a systematic approach to designing multilayer transdermal patches based on therapeutically relevant specifications of the drug. Method: Random search optimization techniques are used to optimize maximum drug release from the patch subject to the therapeutic specifications. Barrier layer thickness and relative concentrations of the drug in the drug-containing layers are used as key design parameters. Results: A patch made of two drug-containing layers of equal thicknesses and relative drug concentrations of 20% and 80%, and a barrier layer with thickness of 14% compared to the total thickness of drug-containing layers was found to be the most optimum design. Conclusion: The proposed design is almost universally applicable and satisfies therapeutically relevant specifications while maximizing drug utilization.

• Controlled release
• diffusion
• multilayer patch
• optimization
• skin
• transdermal delivery