Dual delivery of ginger oil and hexylresorcinol with lipid nanoparticles for the effective treatment of cutaneous hyperpigmentation

Cutaneous hyperpigmentation is a widespread pathology affecting a large slice of the world population. In this work, we propose a treatment approach based on the co-delivery of 4-hexylresorcinol (HR) and ginger oil (GO), using lipid nanoparticles. In specific, HR and GO were encapsulated within nanostructured lipid carriers (NLCs), produced with the high-shear homogenization technique, and using Precirol ATO 5 as solid lipid component. Different NLCs and solid lipid nanoparticles (SLNs) formulations were prepared in order to evaluate any additive or synergistic effect between HR and GO. All the formulations were properly optimized on the basis of the mean size and polydispersity of the nanoparticles population, determined by Dynamic Light Scattering (DLS) technique, and on the basis of stability studies. The rheological behavior of both SLNs and NLCs formulations was evaluated through flow sweep analyses and opportunely adjusted to allow proper topical application. These formulations were then submitted to a cosmetic clinical test on a panel of women presenting cutaneous stains. To this end, CIE L*a*b* and melanin index colorimetrical analyses were carried out to verify the efficacy of the formulations in treating cutaneous hyperpigmentation. Hence, SLNs and especially NLCs have proven to be suitable carriers for a novel treatment approach as an adjuvant in skin concerns in the pharmaceutical and cosmetic fields.