Development and Evaluation of a Polyherbal Neem-Based Emulgel Enriched with Herbal Oils for Enhanced Topical Delivery and Antibacterial Efficacy

Abstract

Introduction: The rising demand for natural and safe dermatological treatments has renewed interest in herbal formulations, particularly those utilizing Azadirachta indica (neem). However, poor solubility and permeability limit its direct application. Emulgels, combining the benefits of emulsions and gels, offer an innovative solution for enhanced topical delivery. Neem (Azadirachta indica), with its well-documented antimicrobial and wound-healing properties but poor solubility, presents an ideal candidate for emulgel formulation when combined with synergistic essential oils (clove, jasmine, rose).

Objective: This study aimed to develop and characterize a stable neem-based polyherbal emulgel enriched with clove, jasmine, and rose oils for improved antibacterial efficacy, stability, and patient acceptability that overcomes neem's solubility limitations while enhancing therapeutic efficacy against common skin pathogens (E. coli and S. aureus) and improving wound healing parameters.

Methods: Neem extract was obtained via Soxhlet extraction and characterized through phytochemical and FTIR analysis. Neem extract was incorporated into an emulgel with Carbopol 934, guar gum, and essential oils. Emulgel formulations were prepared and evaluated for organoleptic properties, rheological characteristics (viscosity: 1050 cP, spreadability: 26.3 g.cm/sec), pH (5.0), stability, and antimicrobial efficacy via disc/well diffusion assays. Antibacterial Testing performed with disc and agar well diffusion methods against Escherichia coli and Staphylococcus aureus were performed. Skin irritancy was assessed through 24-hour patch tests on human volunteers.

Results: The emulgel exhibited optimal pH (5.0), viscosity (1050 cP), and spreadability (26.3 g·cm/s) with no phase separation. FTIR confirmed retention of bioactive compounds (e.g., nimbidin, eugenol). Antibacterial activity: Zones of inhibition ranged from 19–25.5 mm, comparable to gentamicin (30 mm). Non-irritating: Patch tests showed excellent skin compatibility. The optimized formulation demonstrated excellent antibacterial activity (25.5 mm zone against E. coli, 21 mm against S. aureus), representing 75-85% of gentamicin's efficacy. FTIR confirmed retention of bioactive functional groups (C=O at 1723 cm⁻¹, O-H at 3334 cm⁻¹). The emulgel showed no irritation in human tests and maintained stability under various storage conditions.

Conclusion: The neem-based emulgel successfully combines traditional herbal knowledge with modern drug delivery technology, offering a safe, effective natural alternative to synthetic topical antimicrobials with broad-spectrum activity and excellent patient acceptability.