Development and Characterization of Standardized <i>Mesua ferrea</i> Linn. Extract-Loaded Phytosome Gel for Atopic Dermatitis in BALB/c Female Mice

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by itching, scarring, dryness, swelling, and impaired skin barrier function. Multiconstituents-based novel vesicular phytoformulations are gaining significant attention due to their natural bioactives, excellent safety profile, and improved therapeutic activities compared to unformulated herbal drugs and conventional formulations. The study aimed to evaluate the potential of topical phytosome gel with a standardized n-hexane extract of the flowering buds of Mesua ferrea Linn. (SMf) for AD. Methods: The SMf-loaded phytosome was formulated using various proportions of soya lecithin and cholesterol. It was characterized for zeta potential, vesicle size, polydispersity index (PDI), percentage of loading capacity, entrapment efficiency, and morphology by high-resolution transmission electron microscopy (HR-TEM). Subsequently, SMf-loaded phytosome was converted into gel and accessed for the organoleptic properties, pH, viscosity, spreadability, homogeneity, extrudability, syneresis, drug content, stability, ex-vivo skin permeability, drug-excipient compatibility, and therapeutic activity against AD in 1-chloro-2,4-dinitrobenzene (DNCB)-induced BALB/c female mice. Results: The optimized phytosome formulation demonstrated the highest entrapment efficiency, drug loading, highest yield (%), low vesicle size, high zeta potential, and lowest PDI value. The phytosome gel (G-1.0) showed improved pharmaceutical properties compared to the extract-loaded plain gel formulations. The attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) study showed excellent drug-excipient compatibility. The G-1.0 gel demonstrated excellent pharmaceutical outcomes with significantly improved ex-vivo skin permeability, steady-state flux, permeability coefficient, and enhancement ratio compared to extract-loaded plain gel. Additionally, the G-1.0 gel was found non-irritant when applied topically in BALB/c female mice. The G-1.0 showed significantly higher therapeutic activity against AD in DNCB-induced BALB/c female mice than the extract-loaded plain gel. Conclusion: The overall outcome reflected the ability of SMf-loaded phytosome gel to be a novel nanovesicular topical drug delivery system for the possible treatment of AD. However, further clinical studies are necessary to investigate the fate of the novel formulation for an effective AD treatment.