In-vitro drug release and skin irritation studies

This study examined loratadine-loaded ethosomal dispersions and the incorporation of the selected batch into a Carbopol-based gel for potential topical/transdermal use. Eight distinct formulations (F1–F8) were prepared and subsequently evaluated for vesicle size, drug entrapment and in-vitro release. Particle size ranged from 118.6 ± 2.41 nm for F1 to 236.8 ± 4.12 nm for F8; entrapment efficiency ranged from 72.64% to 87.35%. F8 showed the highest entrapment efficiency (87.35%) and drug release was 90.18% over seven hours. The selected F8 dispersion was mixed with Carbopol gel and tested for viscosity, spreadability, pH and drug content. Drug content was found to be 98.46%, while cumulative release reached 87.35% at seven hours. Of the kinetic models assessed, the Higuchi model had the highest coefficient of determination (R² = 0.9997). No visible irritation was recorded during the 14-day observation period. Stability study was carried out for four-weeks under specific storage conditions. Overall, the experimental findings identify F8 as the strongest candidate among the batches tested, based on entrapment, release and measured gel properties. These in-vitro findings justify further investigation but do not establish clinical effectiveness or confirm transdermal delivery in humans. Further studies, including appropriate skin-permeation testing and well-documented stability assessment, are needed.