Improved dermal delivery of FITC-BSA using a combination of passive and active methods

This work presents results on the in vitro penetration of a model macromolecule [fluorescein isothiocyanate‐labeled bovine serum albumin (FITC-BSA)] through porcine skin, mediated with a microneedle skinroller (200‐µm‐length needle) and different novel formulations. After perforating the porcine skin with a microneedle skinroller, the efficiency of delivering FITC-BSA via different novel formulations was evaluated and compared. Formulations, including l‐α‐phosphatidylcholine (PC) liposomes, double emulsions, and double‐encapsulation formulations were used. High‐resolution cryo‐scanning electron microscopy was used to visualize surface morphology and cross‐section of perforated porcine skin. By the use of confocal microscopy, the penetration pathway and penetration depth of FITC-BSA through the perforated porcine skin under different formulations were analyzed. FITC-BSA was extracted from stratum corneum and viable skin, and analyzed by fluorimetry, indicating that there is no significant difference in the amount of FITC-BSA delivered to viable skin by PC‐liposome suspension (12.90 ± 1.25 µg/cm2) versus double‐encapsulation formulations (10.47 ± 0.80 µg/cm2); however, both formulations showed a significant increase as compared with an aqueous solution of FITC-BSA. In this work, double‐encapsulation formulations were used in dermal delivery for the first time and combined with microneedle skinroller treatment, the results showed a high efficiency in delivering macromolecules. © 2011 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:4804-4814, 2011