Purpose: To compare the antibacterial-enhancing efficacy of aloe vera and honey in salicylic acid topical formulations against acne. Method: Six formulations containing 5 % salicylic acid were developed as creams and gels as follows: Formulations S, V and H were creams containing salicylic acid alone (S), salicylic acid with 28 % aloe vera (V), and salicylic acid with 10 % honey (H). Formulations J, M, and B were gels containing salicylic acid alone (J), salicylic acid with aloe vera 20 % (M) and salicylic acid with 12 % honey (B). Each formula was evaluated for colour, odour, pH, viscosity, spreadability, and stability under different temperatures (25, 30, and 60oC) and times (1 hour, 1 day, and 1 week). Furthermore, antibacterial activity was determined using the agar well diffusion method against Escherichia coli, Staphylococcus aureus, Enterobacter spp., Pseudomonas spp., Proteus, and Klebsiella spp. Results: The formulations exhibited distinct colours and odours, with pH values ranging from 4 to 6, viscosities between 3813 and 9813 cP, and spreadability from 10 to 45.5 (g*cm/s). Antibacterial activity, measured by inhibition zone diameters, varied from 0.4 to 2.5 cm against different bacterial strains (p < 0.001). Creams (S, V, and H) exhibited high selectivity, showing strong activity against Gram-positive bacteria such as S. aureus but limited effectiveness against Gram-negative rods like Proteus. In contrast, gel formulations (J, M, and B) showed a broader and more consistent spectrum of activity. All formulations showed stability for up to one month, even with temperature fluctuations, while maintaining a skin-compatible pH. Conclusion: Formulations containing aloe vera and honey increased the antibacterial activity of salicylic acid, thereby making them suitable adjuvants in anti-acne formulations.
