The objective of this study was to investigate the effects of drug amounts (0.1%, 0.2% and 0.3% w/w), amounts of the oil (10%, 15% and 20% w/w of lipid matrix) and types of the oil (soybean oil (S), medium chain triglycerides (M), oleic acids (O) and linoleic acids (L)) in lipid matrix of all-trans retinoic acid (ATRA)-loaded nanostructured lipid carriers (NLCs) for transdermal drug delivery. The ATRA-loaded solid lipid nanoparticles (SLNs) were formulated with 30% w/w cetyl palmitate. All lipid nanoparticles had average sizes between 130 and 241 nm and had negative zeta potentials. The drug loading of all formulations was higher than 95%. The release of drug from all lipid nanoparticles followed zero-order kinetics. The amount of drug released from all the NLCs and SLNs was significantly greater than the drug released from the ATRA suspension. The ATRA flux of the SLNs was higher than the NLCs. The flux of the NLCs containing oleic acid was significantly higher than the other types of oils. The chemical stability at 4 °C, the percentage of ATRA remaining in all the lipid nanoparticles tested was higher than 80%. It can be concluded that both the SLNs and NLCs are promising dermal drug delivery systems for ATRA.

Sponge spicules are needle-like structures and used for dermabrasive treatment of the skin. This research aimed to develop an effective delivery system by using sponge spicules for enhancing skin permeation of bioactive proteins and growth factors from deer antler velvet (DAV). DAV was extracted by sonication and bioactivity studies were evaluated. The size of microspicules (MSs) was reduced and mixed with DAV extract cream. In vitro skin permeation was analyzed by using bovine serum albumin-fluorescein isothiocyanate conjugate (BSA-FITC) as a model macromolecular compound. For in vivo study, DAV extract formulations were applied on the skin of healthy humans, and effects were evaluated. Results showed that DAV extract containing proteins and growth factors increased the proliferation and migration of skin fibroblast cells. This extract was homogeneously mixed with spicule cream. Without blending, MS was 11.89 µm wide and 176.77 µm long; blending time exhibited short and broken MSs (MBs) for short blending (30 s) and fine powder (MF) for long blending (10 min). MS cream showed the highest permeation of BSA-FITC through the skin (2.26-fold enhancement), but it resulted in skin irritation. Therefore, MB cream that increased the permeation of BSA-FITC by 1.94-fold was not significantly different from MS formulations chosen for in vivo study. Applying DAV-containing MB cream on the skin for 14 d decreased the melanin content and erythema value but increased elasticity and hydration. Therefore, the MB-containing cream can enhance the macromolecule delivery through the skin, improve the skin properties, and avoid skin irritation.