Preparation and evaluation of kojic acid dipalmitate solid lipid nanoparticles

Abstract

IntroductionNatural dissolution of kojic acid dipalmitate (KAD) in oil medium makes it difficult to load pharmacologic dose in a stable penetrative drug delivery system as topical dosage form. This study aimed to evaluate solid lipid nanoparticles (SLNs) as a drug delivery platform for the topical delivery KAD. MethodsSLNs were made with five different lipids and homogenization methods. The particle size was analyzed and the best lipid was chosen. Fourier-transform infrared spectroscopy, scanning electron microscopy, and differential scanning calorimetry were done. Then, KAD cream, KAD hydrogel, SLN-based KAD cream, and SLN-based KAD hydrogel were prepared and their release and permeation profile were evaluated on rat skin by Franz cell. ResultThe particle size of SLNs prepared with glycerol monostearate was about 70 nm. The optimum formulation was the combination with GMS 100 mg, KAD 10 mg, and ethanol/acetone in 2.5:1.5; all of which had the KAD entrapment efficiency of about 47%. The release of KAD powder was the fastest, and release from the SLN-based KAD hydrogel was slower than others. The KAD loaded in the SLN had the highest concentration in the stratum corneum, and KAD loaded in hydrogel formulation had the most concentration in the epidermis layer. ConclusionKAD can be loaded in the SLN with fair entrapment efficiency and particle size of <100 nm. KAD loaded in SLN-based cream made the maximum concentration of KAD in the epidermis compared with other formulations. Thus, SLN-based KAD cream is suggested as a proper topical formulation.