Considering a growing demand for medicinal/cosmetic products with natural actives, this study focuses on the low-energy nanoemulsions (LE-NEs) prepared via the Phase inversion composition (PIC) method at room temperature as potential carriers for natural oil. Four different red raspberry seed oils (ROs) were tested, as follows: cold-pressed vs. CO 2extracted, organic vs. non-organic, refined vs. unrefined. The oil phase was optimized with Tocopheryl acetate and Isostearyl isostearate, while water phase was adjusted with either glycerol or an antioxidant hydro-glycolic extract. This study has used a combined approach to formulation development, employing both conventional methods (pseudo-ternary phase diagram − PTPD, electrical conductivity, particle size measurements, microscopical analysis, and rheological measurements) and the methods novel to this area, such as textural analysis and Raman spectroscopy. Raman spectroscopy has detected fine differences in chemical composition among ROs, and it detected the interactions within nanoemulsions. It was shown that the cold-pressed, unrefined, organic grade oil (RO2) with 6.62% saturated fatty acids and 92.25% unsaturated fatty acids, was optimal for the LE-NEs. Textural analysis confirmed the existence of cubic gel-like phase as a crucial step in the formation of stable RO2-loaded LE-NEs, with droplets in the narrow nano-range (125 to 135 nm; PDI � 0.1). The DPPH test in methanol and ABTS in aqueous medium have revealed a synergistic free radical scavenging effect between lipophilic and hydrophilic antioxidants in LE-NEs. The nanoemulsion carrier has improved the biological effect of raw materials on HeLa cervical adenocarcinoma cells, while exhibiting good safety profile, as confirmed on MRC-5 normal

The study showed that the established approach which combines a general experimental design and instrumental, rheological and textural measurements could be appropriate, more objective, repeatable and time and money-saving step towards developing cosmetic emulsions with satisfying, improved or unchanged, consumer-acceptable performance during the reformulation.

Objective The acidic skin pH is one of the regulating factors of skin barrier homeostasis. Topical products as extrinsic factors which influence skin pH could be used for acidification of the skin and consequent beneficial effect. To formulate stabile and safe topical emulsion product with low pH is on‐going challenge and areas interesting to explore are related to the effect of acidic products on the skin pH together with development of protocols for these studies. Aim of our work was to investigate formulations of acidic topical products with glycolic acid (GA) stabilized with long chain alkyl polyglucoside emulsifier, in regard to the specific colloidal structure of the vehicle, together with effect of products with different concentration of acidic active on skin pH. Methods Investigated formulations were basic vehicle and two creams with glycolic acid (concentration 2 and 10 wt%). Microstructure was investigated by polarization microscopy, Raman spectral imaging, thermal analysis and rheological measurements. Effects on the skin were assessed by measurement of biophysical skin parameters in vivo studies (5‐hour, 24‐hour and 7‐days). In vitro screening of antimicrobial activity was performed against bacteria Staphylococcus epidermidis. Results Polarization micrographs and Raman images have shown that GA does not disturb the specific colloidal structure. Together with rheological and thermal analysis obtained results have shown that GA in higher concentrations contributes to vehicles’ lamellar structure. In 5‐hour study the mean values of skin pH ranged from 3.98‐4.25 and 3.89‐4.10 after application of products with smaller and higher GA concentration. GA samples lowered skin surface pH to 5 and less in 24‐hour and 7‐day study, with stronger effect of sample with more GA. Sample with 10% of GA had significant inhibitory effect on growth of S. epidermidis in 1:1 concentration. Conclusions Investigated APG emulsifier could be used as a stabilizer for acidic topical products with GA which are characterized by satisfactory safety profile. Topical products induce acidification of the skin after short‐ and long‐term application without barrier impairment or sign of irritation. Acidification of the skin depends on presence of ingredients which are proton donors and their concentrations.

Due to the lack of skin irritation and skin barrier impairment along with the marked hydration effect, it could be said that the in-vestigated actives incorporated into alkyl polyglucoside emulsi-fier-stabilized creams may be safely applied as ingredients for "tailor-made" cosmetic moisturizers intended for normal and dry skin care, whereas olive oil squalene could be used for the treatment of irritated or sensitive skin as well. [Projekat Ministarstva nauke Republike Srbije, br. TR34031]

During the formulation of liposome-containing products different problems can occur and the selection of a suitable carrier remains the greatest challenge. To estimate feasibility of a novel alkyl polyglucoside surfactant (hydroxystearyl alcohol and hydroxystearyl glucoside) as an emulsifier for cosmetics with liposome-encapsulated plant stem cells, we performed a two-phase study. In the first, the pre-formulation phase, the emulsifier's critical micelle concentration (CMC) and liposome-encapsulated active-emulsifier interactions were determined. The second phase was carried out to develop and characterize a cosmetic emulsion suitable to serve as a carrier for liposomes. The investigated emulsifier, with the obtained CMC value of 0.0085 wt.%, could be classified as liposome-friendly and can be used to develop stable and aesthetically acceptable cosmetics or even prospective pharmaceutical liposome-containing emulsions.