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/cm(2)) versus double-encapsulation formulations (10.47 ± 0.80 µg/cm(2)); 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.