Microemulsion-based Gel for the Transdermal Delivery of Rasagiline Mesylate: in Vitro and in Vivo Assessment for Parkinson's Therapy

Rasagiline mesylate (RSM) is a selective and irreversible monoamine oxidase B inhibitor used for the treatment of Parkinson's disease (PD). However, its unfavorable biopharmaceutical properties, such as extensive degradation in the gastrointestinal tract and first-pass metabolism are responsible for its low oral bioavailability and suboptimal therapeutic efficacy. Here, we report the feasibility of delivering RSM via the transdermal route using RSM containing microemulsion-based gel (RSM-MEG) to achieve effective management of PD. Our in vitro skin permeation studies of RSM-MEG showed significantly higher (at least ~1.5-fold) permeation across rat skin compared to the conventional RSM hydrogel. Our skin irritation studies in rabbits showed that RSM-MEG is safe for transdermal application. Finally, using the rat model of rotenone-induced Parkinsonism, we demonstrated that the topical application of RSM-MEG was equally effective in reversing PD symptoms when compared to oral RSM therapy. Thus, our study confirmed the feasibility and potential of transdermal delivery of RSM via simple topical application of RSM-MEG, and this approach could be an alternative therapeutic intervention for the treatment of Parkinson's disease.