Development and evaluation of penciclovir-loaded solid lipid nanoparticles for topical delivery

The objective of this investigation was to develop solid lipid nanoparticles (SLNs) of penciclovir and evaluate the potential of SLNs as the carrier of penciclovir for topical delivery. Penciclovir-loaded SLNs were prepared by a double (W/O/W) emulsion technique. The SLNs presented spherical with the mean diameter of 254.9 nm. The entrapment efficiency, drug loading and zeta potential were 92.40%, 4.62% and −25.0 mV, respectively. DSC study showed that penciclovir encapsulated in SLNs was in the amorphous form. The cumulative amount of penciclovir penetrated through excised rat skin from SLNs was more than 2-fold that of the commercial cream as a control at 12 h after administration. There was no significant difference of penciclovir content deposited in epidermis between the cream and SLNs administrated for 2, 6 and 12 h, while SLNs increased the cumulative uptake of penciclovir in dermis significantly at the same intervals. Microscopic pictures showed that the interaction between SLNs and the skin surface changed the apparent morphology of stratum corneum and broke the close conjugation of corneocyte layers, which was the possible reason that SLNs increased the permeation of penciclovir into skin dermis. It can be concluded from our study that SLNs provide a good skin targeting effect and may be a promising carrier for topical delivery of penciclovir.