Formulation and Evaluation of Topical Film Forming Roxithromycin Emulgel

The study aims to develop and evaluate a topical film-forming nanoemulgel containing Roxithromycin, an antibiotic targeting Staphylococcus aureus, the cause of impetigo in children. Preformulation studies determined methanol as the best solvent for Roxithromycin, which has a melting point of 118°C. UV-Visible spectrophotometry identified a maximum absorption at 210 nm with an R² value of 0.9991. Solubility studies found Roxithromycin most soluble in black seed oil (43.2 mg/mL), Tween 80 (47.0 mg/mL), and ethanol (40 mg/mL). FTIR confirmed compatibility with excipients. The pseudo-ternary phase diagram indicated that a 1:1 ratio of Smix was optimal, forming a nano emulsion with 40% Smix, 10% oil, and 50% water. Among the formulations, F-II (10% oil, 40% Smix, 50% aqueous phase) was optimized, showing a particle size of 139.7 nm, a zeta potential of -20.2, a PDI of 0.372, drug content of 97.6%, and drug release of 91.2%. Five film-forming emulgels were prepared from this optimized nano emulsion using various polymer concentrations. Formulation FFE-II emerged as optimal, with a pH of 5.98, viscosity of 4079 cps, spread ability of 5.5 cm, extrudability score of 1, drug content of 98.2%, and drug release of 95.5%. Stability studies revealed not much variation in the properties of the emulgel, and release kinetics fit the first-order and Higuchi models with R² values of 0.8164 and 0.9725, respectively. Formulation FFE-III displayed clear, adhesive films with excellent properties and long retention time. Key words: Emulgel, Roxithromycin, Antibiotic, film forming, nano emulsion