Development and evaluation of an alum-loaded gel with antimicrobial potential for the topical management of bacterial folliculitis

Bacterial folliculitis is a common skin disorder characterized by inflammation of hair follicles, primarily caused by Staphylococcus aureus, along with other Gram-positive and Gram-negative bacteria. Existing treatments mainly rely on topical and systemic antibiotics, whose effectiveness is increasingly compromised by resistance and side effects. Here we present a novel approach to the management of bacterial folliculitis, using for the first time an innovative formulation of potassium alum, a natural broad-spectrum antimicrobial and astringent, in the form of hydroxypropyl cellulose (HPC) gel. Hydrophilic gels were made with HPC and hydrated alum at 3, 4, and 5.5 % concentrations. The pH, viscosity, drug content and physical appearance of the formulations was determined. The in vitro antimicrobial activity was evaluated by disc diffusion method against panel of pathogens (S. aureus, E. faecalis, E. hirae, P. aeruginosa, A. baumannii, E. coli, and C. albicans). Release, permeation, and Kp were determined by in vitro and ex vivo (pig skin) Franz diffusion studies. Compatibility of the drug with the excipient was studied by FTIR spectroscopy. The anti-microbial action was dose related: 3% exerted no activity and 5% and 8% demonstrated a marked effect. The ex vivo permeation, Jss, and cumulative release data were the highest for gel 8% alum (G8). FTIR analysis showed no remarkable chemical interactions between alum and the excipients. In vitro efficacy of 5% suspension and 8% cream was moderate although ex vivo there was limited effect due to epidermal barrier activities. This is the first complete report of alum-loaded HPC gel in folliculitis, suggesting the 8% HPC gel to be a clinically novel non-antibiotic topical medicament. Keywords: Potassium alum, hydroxypropyl cellulose, topical gel, bacterial folliculitis, antimicrobial activity, Franz diffusion, FTIR, skin permeation.