Formulation and Development of Adapalene Topical Nanohydrogel Using Different Surfactants and Cosurfactants for Antiacne Activity: In Vitro and Ex Vivo Evaluation

Abstract

A formulation of an adapalene nanohydrogel (ADP-NH) using different surfactants and cosurfactants for topical application was developed and characterized. The best formulation was obtained with nanohydrogel (NH) containing Tween-80- (NH-Tween-80-) incorporated carbopol-940 and ethanol, 0.67% and 3.00% $w/w$ , respectively. The optimized formulations of NH-Tween-80, nanohydrogel containing sodium lauryl sulphate (NH-SLS), and nanohydrogel containing glycerol (NH-glycerol) were separately evaluated to examine their in vitro and ex vivo permeability characteristics and compared with 0.3% dimethyl sulfoxide (control) solution. The polydispersity index of NH-Tween-80, NH-SLS, and NH-glycerol were found to be $0.264\pm 0.312$ , $0.382\pm 0.0045$ , and $0.310\pm 0.412$ , respectively. All NH formulations showed pH within human skin pH ranges throughout the stability period. The NH-Tween-80 revealed 191.22 μg/mL of ADP permeation through Strat-M® membrane which was statistically significant ( $p<0.05$ ) compared to NH-SLS, NH-glycerol, and control solution. At 24 h, NH-Tween-80 demonstrated 305.11 μg/mL of ADP permeation in Wistar rat abdominal skin which was 1.99-, 1.56-, and 4.89-fold higher in comparison with NH-SLS, NH-glycerol, and control solution, respectively. Moreover, the ex vivo permeability of NH-Tween-80 was also compared with conventional gel (market sample) which was 3.38-fold greater at 24 h. During the 6th month of accelerated stability analysis, the NH-Tween-80, NH-SLS, and NH-glycerol demonstrated $99.25\%\pm 0.15$ , $91.23\%\pm 0.41$ , and $96.08\%\pm 0.20$ drug content, respectively. There were no noticeable physical changes observed up to 6 months for NH-Tween-80, while color change was observed in the 1st month and 3rd month of accelerated stability samples of NH-SLS and NH-glycerol, respectively. In this study, only NH-Tween-80 was considered both physically and chemically stable formulation. Therefore, it was concluded that the topical application of ADP-NH containing Tween-80 could be a very promising alternative for the treatment of acne vulgaris.