Microneedle Assisted Transdermal Delivery of Levodopa

Objectives: The present study was designed to investigate the role of microneedle arrays (0.6 and 1.2 mm lengths) in enhancing the in vitro permeation of levodopa (LD) across pig ear skin. Experimental: In vitro skin permeation studies were carried out using Franz diffusion cells for a period of 24 h. A previously developed and validated RP-HPLC-PDA method was used to analyze the samples. Histological examination of skin samples treated with microneedles was carried out to confirm the penetration of microneedles into skin. Results and Discussion: Histological examination of the skin samples clearly showed the micro-conduits in the skin layers after micro-needle application. The penetration depth of micro-needles in skin was found to be about 40-50% of micro-needle length. It was found that increase in the donor volume, i.e., the chemical potential on donor side, increased the permeation of LD. A 9-fold increase in flux with a 16-fold decrease in lag time was observed with 1.2 mm micro-needle application when compared to passive permeation. Conclusion: Micro-needle assisted trans dermal delivery of LD can be an ideal choice for the therapy of parkinson's disease for reducing off-episodes? and side effects pertaining to oral delivery. Further work needs to be done to effectively enhance the transdermal permeation of LD in order to achieve the clinically significant plasma levels.