Permeation of ciclopirox across porcine hoof membrane: effect of pressure sensitive adhesives and vehicles.

The purpose of this study was to investigate the effects of various pressure sensitive adhesives (PSA) on the penetration of ciclopirox across porcine hoof membrane. In addition, the influence of various vehicles on the permeation of ciclopirox from a PSA matrix across porcine hoof membrane was evaluated using a plastic penetration chamber containing poloxamer gel at 32°C. Ciclopirox in poloxamer gel was extracted, derivatized and analyzed by HPLC. Ciclopirox showed highest permeability from an acrylic adhesive with a hydroxyl functional group, and this was followed by styrene–isoprene–styrene, styrene–butadiene–styrene, silicone and polyisobutylene adhesives in order. In addition, N-methyl-2-pyrrolidone (NMP), polypropylene glycol 400 (PPG 400), dimethylsulfoxide (DMSO), Labrasol®, mercaptoethanol and Transcutol® showed excellent permeation enhancing effects in a styrene–isoprene–styrene adhesive. A porcine hoof membrane treated with NMP changed from the non-helical phase to the helical phase, and another treated with DMSO showed a SO peak shift to lower wavelength.