Curcumin-piperine liposomal hydrogel formulation for topical management of atopic dermatitis and associated skin inflammation: optimization, in vitro and in vivo studies.

Abstract

The present study aimed to formulate and evaluate a curcumin-piperine (CUR-PIP) liposome-loaded hydrogel for the topical management of atopic dermatitis (AD). Liposomes were fabricated using the ethanol injection method and optimized through a 3-factorial design, employing phospholipon 90 H and cholesterol as key formulation variables. The effects of these variables on particle size and entrapment efficiency were systematically investigated. The optimized liposomal formulation exhibited a mean particle size of 240.4 nm, a zeta potential of - 27.9 mV, and high entrapment efficiencies of 94% for CUR and 89% for PIP. Comprehensive characterization using differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction confirmed successful drug encapsulation and compatibility between the components. The liposomal hydrogel, prepared using Carbopol 980, demonstrated suitable physicochemical properties, including an appropriate pH (6.3), optimal viscosity, good spreadability, and sustained drug release over 24 h. Ex vivo skin permeation studies indicated enhanced drug retention within the skin (74.23 ± 1.12%) with minimal transdermal permeation, supporting the potential of formulation for localized therapeutic action. Antioxidant assay revealed strong free radical scavenging activity. Furthermore, in vivo evaluation in a DNCB-induced AD mouse model showed that the CUR-PIP liposomal hydrogel significantly reduced erythema, scratching behavior, ear thickness, and spleen index compared to the CUR-PIP suspension and standard dexamethasone groups. Overall, the developed CUR-PIP liposomal hydrogel demonstrated synergistic antioxidant and anti-inflammatory effects, representing a promising and effective topical therapeutic strategy for the management of AD.