Nanoparticle-in-gel system for delivery of vitamin C for topical application.

Hyperpigmentation is a dermal condition of melanocyte proliferation, induced by various factors like ultraviolet radiation producing reactive oxygen species, DNA damage, and apoptosis. The application of topical antioxidants through the different type of formulations can help to prevent oxidative damage to the skin. L-ascorbic acid (vitamin C) is a water-soluble compound and the most abundant antioxidant in human skin, but this vitamin is unstable and loses its potency with poor formulation strategies. Nanotechnology has been effectively used to promote stability and therapeutic activity of various drug molecules. With this context, the objective of the work was set to formulate a topical delivery system of vitamin C nanoparticles incorporated into the polymeric gel. Vitamin C (50 mg) was loaded into ethyl cellulose nanoparticles, of varying concentrations (50-250 mg), by the solvent evaporation method and subsequently incorporated into hydroxypropyl methyl cellulose gels (3, 5, and 7%). The formulations were characterized for various physico-chemical properties such as particle size, drug content, entrapment efficiency, and drug-polymer interactions. In vitro, drug release studies were conducted by using dialysis bag method and Franz diffusion cell for the nanoparticles and gel formulations, respectively. The optimized formulation exhibited sustained release over 8 h. The ex vivo skin permeation studies were performed and the amount of drug retained and released through the skin were determined. The results obtained from the study proved the potentiality and suitability of this novel system to treat hyperpigmentation.