Preparation and physicochemical characterization of rotigotine drug-in-adhesive patch containing crystal growth inhibitor

The objective of this study was to characterize crystallization of Rotigotine (RTG) in a drug in adhesive type patch. RTG was dissolved above 20%w/w in acrylic based adhesives, however its solubility was below 3% in silicone based adhesive. The DSC result of mixture containing acrylate based adhesive and RTG showed that saturated solubility of RTG was 41%w/w in the results of melting enthalpy by DSC. The present of crystal could be confirm by DSC data and the saturated solubility could obtain by melting enthalpy in DSC. The additives for crystal growth inhibitor were respectively selected from polymer, antioxidant and fatty acid. The oleic acid was investigated to be most effective for inhibiting crystal growth and the formation of partially crystalline. In this study, characterization study was performed through Raman and SEM-EDS. The crystal growth rate and crystal inhibition ability were also calculated. The penetration enhancer commonly used enhancer to skin permeation was considered the outstanding crystal inhibition. In permeation study, early permeation ability of the patch was increasing according to increasing content of oleic acid.