Enhancement of stability and dermal delivery of Carissa carandas Linn. leaf extract by liquid crystals

This study aimed to develop liquid crystal (LC) containing the ethyl acetate extract from Carissa carandas Linn. leaves and investigate their stability, release profile, and skin penetration. Various factors affecting the LC formulations were investigated, including types and amounts of oils and surfactants. The physical and chemical stability of C. carandas extract-loaded LCs were investigated in accelerated heating-cooling conditions. Each LC was evaluated for its physical appearance, optical properties, and rheological behavior. Ursolic acid, a major component of C. carandas extract, was used as a marker for the quantitative analysis using high-performance liquid chromatography. The release profile was evaluated by a dialysis method, whereas the skin permeation and penetration were investigated using the Franz diffusion cell. The results showed that LC formulations could significantly enhance the chemical stability of C. carandas extract. LC1, composed of 2.5% w/w coconut oil, 30% w/w Tween® 85, and 67.5% w/w DI water, was the most suitable formulation which could significantly release the extract from the formulations and deliver the active into the deeper skin layer with no permeation through the skin into blood circulation. After 24 h, 42.7 ± 2.5% w/w of ursolic acid was released from LC1 and 22.8 ± 3.2% w/w penetrated into the viable epidermis and dermis layer. Therefore, LC1 was suggested as an innovative delivery system effective for application in cosmetics. [Display omitted] •Liquid crystal (LC) enhanced the chemical stability of C. carandas extract.•Ursolic acid from LC penetrated into the viable epidermis and dermis layer.•LC was a safe and effective delivery system to be applied in the cosmetic area.