Dermal Delivery of Korean Red Ginseng Extract: Impact on Storage Stability of Different Carrier Systems and Evaluation of Rg1 and Rb1 Skin Permeation Ex Vivo

Radical scavenging effect of skin delivery systems using Korean red ginseng extract and assessment of their biocompatibility with human primary dermal fibroblasts and HaCaT keratinocytes

Korean red ginseng (KRG) extract is proposed for cosmetic use, but no data on biological effects of KRG-loaded vehicles exist. The study aimed to optimize new multi- and monophase vehicles for KRG extract delivery, assess their biocompatibility and evaluate their radical scavenging effect in vitro. Storage stability of oil-in-water nanoemulsions (NEs) and hydroalcoholic gels (2 % w/w KRG) was assessed over twelve weeks using dynamic light scattering, rheology and pH measurements. Release profiles of ginsenosides Rb1 (more hydrophilic) and Rg1 (moderately lipophilic) through a cellulose membrane were also investigated employing Franz diffusion cells. Antioxidant potential and biocompatibility were assessed via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and cell viability assays. Vehicles remained stable over twelve weeks at 8 °C (NEs Dh stable, gel viscosity + 3.5 %). Diffusion studies showed higher release of Rg1 vs. Rb1 (7.10 vs. 1.39 µg/cm-2 after 28 h). KRG-formulations demonstrated good biocompatibility with primary human dermal fibroblasts and HaCaT keratinocytes (72-94 % viability). Radical scavenging capacity of KRG extract did not differ between pure and incorporated form and was lower than that of a Hypericum extract or ascorbic acid. Results render KRG-formulations a potentially promising alternative to conventional antioxidants used in daily products.

Surfactants for stabilization of dermal emulsions and their skin compatibility under UVA irradiation: Diacyl phospholipids and polysorbate 80 result in high viability rates of primary human skin cells

Phospholipids are versatile formulation compounds with high biocompatibility. However, no data on their effect on skin in combination with UVA radiation exist. Thus, it was the aim of this work to (i) develop o/w nanoemulsions (NEs) differing in surfactant type and to investigate their physicochemical stability at different storage temperatures, (ii) establish a standardized protocol for in vitro phototoxicity testing using primary human skin cells and (iii) investigate the phototoxicity of amphoteric phospholipids (S45, S75, E80, S100, LPC80), sodium lauryl ether sulfate (SLES) and polysorbate 80 (PS80). Satisfying systems were developed with all surfactants except S100 due to low zeta potential (-21.4 mV ± 4.69). SLES and PS80-type NEs showed the highest stability after eight weeks; temperature-dependent variations in storage stability were most noticeable for phospholipid surfactants. For phospholipid-based NEs, higher phosphatidylcholine content led to unstable formulations. Phototoxicity assays with primary skin fibroblasts confirmed the lack of UVA-related phototoxicity but revealed cytotoxic effects of LPC80 and SLES, resulting in cell viability as low as 2.7 % ±0.78 and 1.9 % ±1.57 compared to the control. Our findings suggest that surfactants S45, S75 and PS80 are the most promising candidates for skin-friendly emulsifiers in sensitive applications involving exposure to UV light.

Spruce Balm-Based Semisolid Vehicles for Wound Healing: Effect of Excipients on Rheological Properties and Ex Vivo Skin Permeation

The treatment of chronic wounds, an important issue with the growing elderly population, is increasingly hindered by antibiotic resistance. Alternative wound care approaches involve the use of traditional plant-derived remedies, such as purified spruce balm (PSB), with antimicrobial effects and the promotion of cell proliferation. However, spruce balm is difficult to formulate due to its stickiness and high viscosity; dermal products with satisfying technological properties and the scientific literature on this topic are scarce. Thus, the aim of the present work was to develop and rheologically characterize a range of PSB-based dermal formulations with different hydrophilic/lipophilic compositions. Mono- and biphasic semisolid formulations based on different compounds (petrolatum, paraffin oil, wool wax, castor oil, and water) were developed and characterized by their organoleptic and rheological measurements. A chromatographic method of analysis was established, and skin permeation data were collected for pivotal compounds. The results showed that the dynamic viscosity ranged from 10 to 70 Pas at 10/s for the different shear-thinning systems. The best formulation properties were observed for water-free wool wax/castor oil systems with 20% w/w PSB followed by different water-in-oil cream systems. Skin permeation through porcine skin was observed for different PSB compounds (e.g., pinoresinol, dehydroabietic acid, and 15-hydroxy-dehydroabietic acid) using Franz-type diffusion cells. The permeation potential of wool wax/castor oil- and lard-based formulations was shown for all the analyzed substance classes. The varying content of pivotal compounds in different PSB batches collected at different timepoints from different spruce individuals might have contributed to observed differences in vehicle performance.