Nanoliposomes@Transcutol for In Vitro Skin Delivery of 8-Methoxypsoralen

: 8-methoxypsoralen is the most common drug in psoralen plus ultraviolet light irradiation therapy for the treatment of severe psoriasis. Despite of the efficacy, its classic oral administration leads to several serious adverse effects. However, the topical psoralen application produces a drug skin accumulation lower than that obtained by oral administration, due to the drug low skin permeability. In this paper, 8-methoxypsoralen loaded Penetration Enhancer-containing Vesicles were prepared using soy phosphatidylcholine and the penetration enhancer Transcutol® (5% or 10%) and characterized in terms of size, polydispersity index, zeta potential and encapsulation efficiency. No statistically significant differences in both size (~135 nm) and encapsulation efficiency (~65%) were found for different Transcutol® concentration. Transdermal delivery study assessed by Franz diffusion cells, showed that the 8-methoxypsoralen mainly accumulated into the stratum corneum. Moreover, after Penetration Enhancer-containing Vesicles application, the drug recovered in this layer is almost double of that delivered by conventional liposomes, while no significant difference was found from the different Transcutol® concentrations. Finally, biocompatibility checked by an MTT assay, demonstrated that the incubation of human keratinocytes for 24 h with 8-methoxypsoralen loaded Penetration Enhancer-containing Vesicles did not significantly reduce cell viability.