The Depigmentation Effect of Hydroquinone-loaded Nanostructured Lipid Carriers (NLCs) on the Rat Skin

The goal of this research is the localization of hydroquinone (HQ) to the epidermis for the treatment of
hyperpigmentation in rat skin. For this purpose, nanostructured lipid carrier (NLC) was selected for the
dermal delivery of HQ. A 2 3 factorial design was used in this study, and eight NLCs were prepared with
a cold homogenization technique. HQ entrapment efficiency (EE %), particle size, morphology, thermal
behavior of NLCs, and permeability parameters through rat skin with NLC in comparison with HQ aqueous
solution (HQ-S) with Franz diffusion cells were evaluated. Based on the optimization technique, the best
NLC was selected and in the in vivo experiment, the depigmentation effect of optimized NLC in comparison
with that of HQ-S was evaluated. The results showed that the main problem for HQ permeability was fast
permeation and low concentration in the site of action. Partitioning from aqueous donor phase into skin
rate was the limiting step for drug flux, and this can be solved using NLC. The decrease in maximum
flux obtained by NLC was according to formulation 8. Regression analysis suggested a significant and
direct effect of the S/L ratio and the percentage of liquid lipids on the drug loading. NLC decreased drug
permeation through rat skin basically due to sustained release properties.