Preparation and Evaluation of Nanoemulsion Formulation Containing Kojic Acid and Kojyl 3-aminopropylphosphonic Acid

The kojyl 3-aminopropylphosphonic acid (KAP) was synthesized by kojic acid (KA) with a 3-aminopropylphosphonic acid. Which is more stable than KA and showed better skin penetration and anti-pigmentation efficacy in melanocytes. However, up till now, there have been no studies aimed at incorporating KAP into an emulsion system and evaluating its effectiveness. We develop a novel skin-lightening agent using KAP as the active ingredient and a low-cytotoxic nanoemulsion as the delivery system in this study. The sorbitan monooleate and polysorbate surfactants with polyethylene glycol (PEG) co-surfactant were used to generate a nanoemulsion system. The transparency and particle size stability over various storage times indicate that the formulated nanoemulsions are suitable for long-term storage. Besides, results demonstrate that the anti-pigmentation function of KA and KAP-containing nanoemulsions (NE-KA and NEKAP) evidently outperformed that of the non-packed KA and KAP group. Despite having the lowest concentration among other treatments, NE-KAP was able to reduce melanin content to approximately 80% of the blank. Our findings suggest that this newly developed nanoemulsion containing KAP could potentially serve as a sustainable alternative to hydroquinone for treating dermal hyperpigmentation disorders in future applications.