Development and evaluation of topical formulations for a novel skin whitening agent (AP736) using Hansen solubility parameters and PEG-PCL polymers

In this study, we aimed to develop a new topical delivery system in which AP736 is not only physically stable, but also suitably delivered to the skin. By calculating each HSP (Hansen Solubility Parameters), ethylenedioxy moiety-containing compounds could be easily selected for the formulation ingredients of AP736. Although the highest solubility of AP736 in diethylene glycol monoethyl ether make AP736-incorporated water in oil emulsions well formed, the recrystallization of AP736 was observed in oil in water emulsions. Therefore, we fabricated polymeric nanoparticles (PNPs) in order to encapsulate AP736. Three different PEG-PCL polymers with various chain lengths and ethylenedioxy moiety-containing surfactants (i.e. Choleth) were used. The prepared PNPs had a mean particle size from 50nm to 200nm. Most of PNPs showed the good encapsulation efficiency up to 90%. In particular, Choleth-24 had a significant role in encapsulating AP736 in PNPs. After encapsulation of AP736, no significant changes were observed in the sizes of tested PNPs within 4 weeks. Further, the recrystallization of AP736 was not observed in oil in water emulsions after 24 weeks of storage at 40°C. In vitro permeation study using Strat-M, PNPs containing Choleth-24 showed the faster release pattern compared to PNPs using Tween 80 and saturated in DI water. These studies demonstrated that these PNPs might be an effective vehicle for topical application of AP736.Graphical abstract
Source: International Journal of Pharmaceutics - Category: Drugs & Pharmacology Source Type: research