Whitening effect of kojic acid dipalmitate loaded nanosized ethosomal gel for the treatment of hyperpigmentation: In vitro and in vivo characterization.

Background: In recent years, the demands of depigmenting agents in cosmetics have been increased to treat skin conditions such as hyperpigmentation and melasma. Tyrosinase is a major enzyme involve in hyperpigmentation. Kojic acid dipalimate (KAD) is an ester derivative of kojic acid and exhibit excellent tyrosinase inhibiting activity on human skin.

Objective: To develop and characterize a novel topical delivery system for KAD by using ethosomes and their in vitro, in vivo characterization for the treatment of hyperpigmentation.

Methods: Different KAD loaded ethosomal suspensions were prepared using soy phosphatidylcholine, ethanol, propylene glycol, and water with cold method. These formulations were evaluated for size, zeta potential, Polydispersity index, entrapment efficiency, FTIR spectroscopy, and scanning electron microscopy (SEM). Afterward, the stability of optimized gel was checked and the in vivo studies were carried out in order to evaluate the skin benefits.

Results: The optimized formulation has zeta potential, size, and entrapment efficiency of -23.4 mV, 148 nm, and 90.0008%, respectively. SEM results showed vesicles were spherical in shape. Ethosomal gel had a good stability at lower temperature (8, 25°C). In addition, ethosomal gel gives significant decrease in skin melanin, erythema, and sebum level while it causes improvement in skin hydration level and elasticity during non-invasive in vivo studies.

Conclusion: The overall findings indicated that the prepared KAD loaded ethosomal formulation was stable and provides deep penetration of KAD into the skin. It offers a promising therapeutic approach for use in skin hyperpigmentation as it has skin whitening and moisturizing effects.