Formulation and Evaluation of Bakuchi Oil Loaded Hydrogel for the Management of Common Skin Conditions

Abstract

Background: Skin disorders such as acne vulgaris, eczema, psoriasis, and superficial fungal infections impose a considerable therapeutic burden worldwide.Topical drug delivery offers significant advantages over systemic routes, including avoidance of hepatic first-pass metabolism, targeted drug deposition, and improved patient compliance.Bakuchi oil, derived from the seeds of Psoralea corylifolia L. (Fabaceae), is a classical Ayurvedic remedy rich in bakuchiol, psoralen, isopsoralen, and various fatty acids.It has well-documented anti-inflammatory, antimicrobial, antifungal, and antioxidant activities.Despite its therapeutic potential, incorporation of Bakuchi oil into a stable, cosmetically elegant, and effective topical formulation remains challenging owing to its hydrophobic nature, potential for skin irritation, and physicochemical instability.Objectives: The present study aimed to formulate and optimize a Carbopol 940-based hydrogel loaded with Bakuchi oil for topical application, and to systematically evaluate its physicochemical properties, in vitro drug release behaviour, release kinetics, ex vivo skin permeation, antimicrobial activity, anti-inflammatory activity, and stability.Methods: Seven hydrogel formulations (F1-F7) were prepared by varying the concentrations of Carbopol 940 (0.5-1.5% w/v) and Transcutol-P (2-6% v/v) as the permeation enhancer, with Bakuchi oil at three levels (3, 5, 7% v/v).Preformulation studies encompassing organoleptic characterisation, solubility profiling, phytochemical screening, ultraviolet (UV) spectroscopy, and Fourier-transform infrared (FTIR) spectroscopy were performed.The optimised formulation (F5) was selected on the basis of desirability composite scoring and subjected to in vitro drug release using a Franz diffusion cell, release kinetics modelling (zero order, first order, Higuchi, Korsmeyer-Peppas), ex vivo permeation through excised rat skin, agar well-diffusion antimicrobial assay, albumin denaturation-based antiinflammatory assay, and accelerated stability testing as per International Council for Harmonisation (ICH) Q1A(R2) guidelines.Results: All formulations exhibited acceptable pH (5.8-6.1),adequate viscosity (3820-9820 cPs), satisfactory spreadability, and drug content within pharmacopoeial limits (95-105%).The optimised formulation F5 (Carbopol 940: 1.0%; Transcutol-P: 6%; Bakuchi oil: 5% v/v) demonstrated a cumulative drug release of 94.6±1.0%over 24 hours, following an anomalous (non-Fickian) diffusion mechanism as described by the Korsmeyer-Peppas model (R² = 0.9921, n = 0.62).F5 exhibited significantly greater antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans compared to crude oil alone, and achieved 92.6% albumin denaturation inhibition at 400 µg/mL.Stability testing confirmed retention of physicochemical integrity for three months under both long-term (25°C/60% RH) and accelerated (40°C/75% RH) conditions.Conclusion: The Bakuchi oil loaded Carbopol 940 hydrogel represents a promising, stable, and effective topical delivery platform for the management of common skin conditions.Future clinical trials and scale-up studies are warranted to establish its safety and commercial viability.