The effect of ceramides on skin absorption by Raman spectroscopy.

INTRODUCTION: Ceramides are essential epidermal constituents that play a critical role in skin moisturization treatment as a raw material in cosmetics formulation. Recently, ceramides have been known to be frequently applied in various cosmetic formulations. Despite ceramide's beneficial characteristics, academic research regarding ceramides and their skin absorption remains insufficient. Therefore, our study conducted clinical research employing Raman spectroscopy to investigate the effects of ceramides on skin absorption to enhance the understanding of ceramides' dermatological functionality and their topical application in cosmetics science. MATERIALS AND METHODS: Twenty healthy individuals with dry skin have participated in this clinical trial. In this double-arm designed trial, the test group received an investigational product with ceramides (5000 ppm) and a control group received an investigational product without the ceramides while all other components remained identical. The subjects visited the clinical research center and acclimatized for 30 min in constant humidity and temperature for equilibrium, subsequently conducting a measurement. Before the trial, the research subject's target site (lower arm area) was kept clean, devoid of any cosmetic administering 24 h before the trial when investigational product was topically applied. RESULTS: Our findings with Raman spectroscopy statistically demonstrate that skin absorption amount, speed and depth for both groups improved overall (p < 0.05) after administration of the investigational product. Notably, the test group received an investigational product with ceramides (5000 ppm) indicating superior effectiveness across all parameters compared to a control group from comparison analysis of each parameter (p < 0.05). CONCLUSION: This study concludes that ceramide-containing cosmetics provide a beneficial effect on skin absorption via visual and statistical results of Raman spectroscopy analysis.

Surfactant-stable and pH-sensitive liposomes coated with N-succinyl-chitosan and chitooligosaccharide for delivery of quercetin.

Layer-by-layer (LbL) self-assembly of multilayered liposomes is used to improve the stability of conventional liposomes. In this study, the LbL technology was used to prepare novel multilayered liposomes from chitooligosaccharide and N-succinyl-chitosan. We propose that this preparation can be used as a transdermal drug delivery system (TDDS) to enhance stability against surfactants and control drug release. Particle size increased with the number of layers in the multilayer and the zeta potential varied between positive and negative values with alternate deposition of polyelectrolytes. Finally, approximately 300-400nm-thick four-layered liposomes were prepared. These liposomes were more stable against surfactants and showed a relatively high release of quercetin at pH 5.5 than the uncoated liposomes as assessed via in vitro drug release and skin permeation studies. In summary, the multilayered liposomes showed potential for use as a surfactant-stable TDDS that effectively enhanced the permeation of quercetin, a poorly soluble drug, into the skin.