Nanoemulgel of Aegle marmelos Essential Oil: Characterization, Ex vivo Permeation and Antimicrobial Evaluation for Acne

Abstract

The focus of study was on the development and characterization of nanoemulsion-based gel (nanoemulgel) containing Aegle marmelos (bael) leaf essential oil for potential application in acne management. The essential oil was extracted via hydrodistillation with a yield of 0.35±0.1% (w/v) and analyzed using GC-MS, which identified 41 compounds with D-limonene (75.81%) as the predominant constituent. Spontaneous emulsification technique was employed to prepare nanoemulsion with an optimized surfactant-to-co-surfactant ratio of 1:1, resulting in stable nanoparticles with an average size of 109.5±7.59nm, polydispersity index of 0.274±0.04, and zeta potential of -0.852±0.176mV. Nanoformulation was incorporated into a 2% Carbopol 934 gel to form nanoemulgel with appropriate viscosity (597.1 mPa·s), spreadability (8.32g·cm/s), and pH (4.42±0.02). Ex vivo permeation studies using rat abdominal skin demonstrated superior delivery with the nanoemulsion (7,200 µg/cm²) compared to nanoemulgel (6,500µg/cm²) and pure essential oil (5,000µg/cm²) over 24hours. In vitro studies revealed 85% release of nanoemulsion within 10 hours versus sustained release for nanoemulgel over 48 hours. Antimicrobial assays showed significant activity against acne-causing bacteria with a minimum inhibitory concentration of 2.5% against both S. aureus and S. epidermidis. Essential oil exhibited the largest inhibition zones (30.00±0.00mm against S. aureus; 17.33±0.58mm against S. epidermidis), followed by nanoemulsion and nanoemulgel formulations, which performed comparably to standard antibiotics. These findings suggest that A. marmelos essential oil nanoemulgel represents a promising natural alternative for acne treatment, offering enhanced stability, controlled release, and effective antimicrobial activity while addressing concerns of antibiotic resistance.