Investigation of Polymeric Micellar Nanoparticles of Amlodipine Besylatefor Transdermal Delivery

Objectives: The objective of this study was to formulate and investigate amlodipine besylate loaded polymeric micelles and their effect on enhancing transdermal permeation of the poorly water-soluble drug via transdermal films. Methods: Pluronic F127 and Pluronic F68 polymers were chosen to prepare micelles in different drug - polymer ratios. Prepared formulations were characterised for surface morphology, micelle size, polydispersity index, zeta potential, loading efficiency, percentage drug weight in micelles and stability. Optimized amlodipine micelle dispersions were incorporated into hydroxypropyl methylcellulose K100 and polyvinyl pyrrolidone K30 transdermal films prepared by the solvent casting method. These films were evaluated for thickness, percentage weight variation, folding endurance, moisture absorbance, percentage drug content, ex vivo permeation and in vivo skin irritation. Results: Selected micelle formulations had the desired vesicle size, homogeneity and stability. Scanning electron microscopy show spherical vesicles. Micelle incorporated transdermal films were smooth, flexible, translucent and mechanically strong. The ex vivo skin permeation studies reveal that the flux of amlodipine besylate from the micelle incorporated transdermal films was significantly higher than that containing the free drug, confirming the drug solubilizing effects of micelles. Reconstitution of micelles from optimized films revealed that the original characteristics of the micelles were intact. Studies in Wistar rats showed that the prepared transdermal films were free of irritation potential when evaluated by the Draize dermal irritation scoring system. Conclusion: Beside their solubilizing effect, Pluronic micelles could be useful as novel drug carriers for enhancing transdermal permeation of Amlodipine besylate and thus its bioavailability.