Preparation and Characterization of Transethosome Formulation for the Enhanced Delivery of Sinapic Acid

Sinapic acid (SA) is a bioactive phenolic acid; its diverse properties are its anti-inflammatory, antioxidant, anticancer, and antibacterial activities. The bioactive compound SA is poorly soluble in water. Our goal was to formulate SA-transethosomes using thin-film hydration. The prepared formulations were examined for various parameters. In addition, the optimized formulation was evaluated for surface morphology, in-vitro penetration studies across the Strat M®, and its antioxidant activity. The optimized formulation (F5) exhibited 74.36% entrapment efficacy. The vesicle size, zeta potential, and polydispersity index were found to be 111.67 nm, -7.253 mV, and 0.240, respectively. The surface morphology showed smooth and spherical vesicles of SA-transethosomes. In addition, the prepared SA-transethosomes exhibited enhanced antioxidant activity. The SA-transethosomes demonstrated considerably greater penetration across the Strat M® membrane during the study. The flux of SA and SA-transethosomes through the Strat M® membrane was 1.03 ± 0.07 µg/cm2/h and 2.93 ± 0.16 µg/cm2/h. The enhancement ratio of SA-transethosomes was 2.86 ± 0.35 compared to the control. The SA-transethosomes are flexible nano-sized vesicles and are able to penetrate the entrapped drug in a higher concentration. Hence, it was concluded that SA-transethosome-based approaches have the potential to be useful for accentuating the penetrability of SA across the skin.

Phospholipid Vesicles for Dermal/Transdermal and Nasal Administration of Active Molecules: The Effect of Surfactants and Alcohols on the Fluidity of Their Lipid Bilayers and Penetration Enhancement Properties

This is a comprehensive review on the use of phospholipid nanovesicles for dermal/transdermal and nasal drug administration. Phospholipid-based vesicular carriers have been widely investigated for enhanced drug delivery via dermal/transdermal routes. Classic phospholipid vesicles, liposomes, do not penetrate the deep layers of the skin, but remain confined to the upper stratum corneum. The literature describes several approaches with the aim of altering the properties of these vesicles to improve their penetration properties. Transfersomes and ethosomes are the most investigated penetration-enhancing phospholipid nanovesicles, obtained by the incorporation of surfactant edge activators and high concentrations of ethanol, respectively. These two types of vesicles differ in terms of their structure, characteristics, mechanism of action and mode of application on the skin. Edge activators contribute to the deformability and elasticity of transfersomes, enabling them to penetrate through pores much smaller than their own size. The ethanol high concentration in ethosomes generates a soft vesicle by fluidizing the phospholipid bilayers, allowing the vesicle to penetrate deeper into the skin. Glycerosomes and transethosomes, phospholipid vesicles containing glycerol or a mixture of ethanol and edge activators, respectively, are also covered. This review discusses the effects of edge activators, ethanol and glycerol on the phospholipid vesicle, emphasizing the differences between a soft and an elastic nanovesicle, and presents their different preparation methods. To date, these differences have not been comparatively discussed. The review presents a large number of active molecules incorporated in these carriers and investigated in vitro, in vivo or in clinical human tests.