In vitro Kinetic Release Study, in vivo Hydration and Moisturizing Effect of Peel-off Oil-in-Water (O/W) Nanoemulsion Containing Kojic Monooleate for Topical Application

Background: Kojic monooleate (KMO) contains tyrosinase inhibitor and exhibits strong antioxidant activity makes it a good candidate to be incorporated into a formulation for topical application. A peel-off was chosen to ensure a better hydration effect and permeability of KMO into the skin. The objectives of this research were to analyze the kinetic release study of peel-off oil-in-water O/W nanoemulsion containing KMO and evaluate the moisturizing and hydration effect towards human volunteers. Methods: The peel-off formulation was developed by adding 27.61% w/w polyvinyl alcohol (PVA) and 1.05% w/w propylene glycol (PG). The study was performed by using Franz cell, tewameter and corneometer to analyze the release rate of KMO from peel-off O/W nanoemulsion, moisturizing, and hydration effect of formulation towards humans after 180 min of application, respectively. Results: The final formulation has a pH of 4.74, conductivity of 7.47 ± 4.05 x 10-3 𝜇S/cm, viscosity 0.1058 Pa·s and spreadability of 61.86 ± 1.71 g·cm/s. It also disports 79.99 ± 2.53 % released of KMO after 180 min of study time. The results of the hydration effect of the formulation towards human volunteers’ skin suggested that the peel-off O/W nanoemulsion containing KMO does increase the hydration of the skin by 12.33% due to the occlusive effect of KMO. Conclusion: In summary, this study presents new findings in the kinetic release study, hydration and moisturizing effect of peel-off O/W nanoemulsion containing KMO for topical application.