Cellulitis is a common bacterial skin infection predominantly caused by Staphylococcus aureus and Streptococcus pyogenes, often requiring prolonged antibiotic therapy that may lead to adverse effects and antimicrobial resistance. This study presents a preliminary in-vitro evaluation of a Calendula oil-based emulgel against Staphylococcus aureus, a common pathogen associated with cellulitis. The findings highlight its antimicrobial potential along with favourable physicochemical and formulation characteristics, supporting its promise for further preclinical and clinical investigation. The oil was authenticated through organoleptic, physicochemical, phytochemical, and FTIR evaluations, confirming its purity and bioactive profile. A validated UV–Vis spectrophotometric method (λmax 237 nm, R² = 0.9956) ensured reliable quantification of the oil. Formulation F2 exhibited optimal rheological behaviour with pseudo-plastic flow, appropriate yield stress (~550 Pa), rapid drying time (38 ± 10 sec), and uniform drug distribution (95.75 ± 0.84%). The in vitro release profile demonstrated sustained diffusion, with cumulative release of 45.8% at the final time point. Antimicrobial testing against S. aureus revealed that the emulgel (6.67 ± 0.577 mm inhibition zone) was comparable to clindamycin (6.33 ± 0.577 mm), while the essential oil alone exhibited higher activity (8 ± 1.00 mm). These findings confirm that Calendula officinalis oil emulgel possesses desirable physicochemical, rheological, and antimicrobial properties, making it a promising topical therapeutic for cellulitis.

Palak Karia, Sumedha Nadkar, Piyush Hande, Anuj Avhad, Sahil Jaiswal, Soundarya Thanvi, Om Singh

Cellulitis; Calendula officinalis; Emulgel; Essential oil; In vitro drug release; Topical formulation.