Purpose:To study the effects of varying lipid concentrations, lipid and oil ratio, and the addition of propylene glycol and lecithin on the long-term physical stability of nanostructured lipid nanocarriers (NLC), skin hydration, and transepidermal water loss. Methods: The various NLC formulations (A1-A5) were prepared and their particle size, zeta potential, viscosity, and stability were analyzed. The formulations were applied on the forearms of the 20 female volunteers (one forearm of each volunteer was left untreated as a control). The subjects stayed for 30 minutes in a conditioned room with their forearms uncovered to let the skin adapt to the temperature (22°C ± 2°C) and humidity (50% ± 2%) of the room. Skin hydration and skin occlusion were recorded at day one (before treatment) and day seven (after treatment). Three measurements for skin hydration and skin occlusion were performed in each testing area. Results: NLC formulations with the highest lipid concentration, highest solid lipid concentration, and additional propylene glycol (formulations A1, A2, and A5) showed higher physical stability than other formulations. The addition of propylene glycol into an NLC system helped to reduce the particle size of the NLC and enhanced its long-term physical stability. All the NLC formulations were found to significantly increase skin hydration compared to the untreated controls within 7 days. All NLC formulations exhibited occlusive properties as they reduced the transepidermal water loss within 7 days. This effect was more pronounced with the addition of propylene glycol or lecithin into an NLC formulation, whereby at least 60% reduction in transepidermal water loss was observed. Conclusion: NLCs with high lipid content, solid lipid content, phospholipid, and lecithin are a highly effective cosmetic delivery system for cosmetic topical applications that are designed to boost skin hydration.

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The qualities of oils extracted from fresh and dried palm-pressed mesocarp fiber were evaluated. The means of extraction included conventional solvent extraction and supercritical carbon dioxide (SC-CO 2 ) extraction with and without addition of ethanol. Extraction efficiency using pure SC-CO 2 and the effect of moisture content on efficiency were studied. Minor components, such as vitamin E, carotenoids, squalene and phytosterols, obtained by different methods were compared. The quality of oil recovered from fresh palm-pressed fiber is generally better than that of oil recovered from dried fiber. The SC-CO 2 extraction rate was lower for fresh fiber than for dried fiber. The incorporation of ethanol with SC-CO 2 resulted in oil with higher oxidative stability than did SC-CO 2 alone. Concentrations of minor components and the acylglycerol compositions of the oils extracted from both types of fibers were similar. SCHEME 1 FIG. 1. Effect of CO 2 flow rate on the extraction of residual oil from dried palm-pressed fiber using supercritical CO 2 (SC-CO2) and n-hexane.

Supercritical carbon dioxide (SC‐CO2) was used to extract palm oil from palm mesocarp (Elaeis guineensis). The conditions surveyed were 40 to 80C and 14 to 30 MPa. The free fatty acid content in SC‐CO2 extracted palm oil was found to be 0.61% as compared to 3.15% in commercial crude palm oil (CPO). The average peroxide value of the SC‐CO2 extracted CPO was 1.68 meq O2/kg, which indicated that SC‐CO2 extraction does not induce the formation of undesirable peroxides and hydroperoxides. The deterioration of bleachability index of SC‐CO2 extracted palm oil met the specification of fairly good CPO with average value of 2.60. The oxidative stability of SC‐CO2 extracted palm oil was slightly lower than commercial and n‐hexane extracted CPO. The pro‐oxidants such as iron and copper were significantly reduced in the SC‐CO2‐produced oil. Minor components such as carotenes, vitamin E (e.g., tocopherols and tocotrienols), phytosterols and squalene were co‐extracted during the SC‐CO2 extraction. The overall quality of SC‐CO2 extracted CPO appears equivalent to those obtained by commercial processing of CPO.