Natural lipids in nanostructured lipid carriers and its cytotoxicity

Nanostructured lipid carriers (NLCs) are active carrier systems which modulate the sustained release of actives and protect unstable compounds against degradation. NLCs can also protect skin from sun light, due to its particulates nature, which gives them intrinsic scattering properties. In this work, we present the preparation of NLCs using natural lipids and its cytotoxicity profile. It was used a vegetal butter with melting point (m.p.) ~32-40°C, an animal wax (m.p. 35-40°C) and a vegetal oil (boiling point ~120-150°C). NLCs were prepared by hot high pressure homogenization method and particles were characterized by average size (Zave), polydispersity index (PDI) and zeta potential (PZ) (Fig.1). The thermal behavior of the NLCs was studied using Differential Scanning Calorimetry (DSC). All the formulations were followed up for 60 days in order to evaluate their stability. NLCs exhibited a Zave around 150-200 nm, PDI less than 0.2 and PZ varying from −25 to −40 mV. The m.p. for the lyophilized NLCs was about 40-56°C. Cytotoxicity of the formulations were evaluated for human keratinocytes (HaCaT) and melanocytes (Melan-A) in the exponential growth phase. Cell viability was used as indicator of cytotoxicity and determined after 4 days of culture by MTT assay. It was found that the NLC formulations were not toxic against HaCaT and Melan-A cells. Results showed that the NLCs produced are potential carriers for nanocosmetics and sunscreen products.