The antibacterial and anti-inflammatory potential of rosemarinic acid (ROA), a naturally occurring ester of caffeic acid has been well reported. Antibacterial effect of ROA is attributed to nucleoid damage with an increase in spatial division and condensation of genetic material. ROA has been found dynamic against many human pathogenic bacterial strains but its inhibitory prospective has never been established against skin inflammations caused by Propionibacterium acne. The skin surface in acne prone areas is colonized with Staphylococcus aureus and Propionibacterium acnes which contribute to inflammation and acne. Resistance to current antimicrobial therapies suggested the need to explore new antimicrobial agents against acne. Present work included the preparation of ROA-loaded niosomes and their in vitro antimicrobial evaluation against P. acne and S. aureus. This work also included the development of niosomal gel of rosmarinic acid for sustained delivery to bacteria infected cells. Niosomes of rosmarinic acid were formulated by reverse phase evaporation method using different ratio of span 85 and cholesterol. The prepared formulations were evaluated for its vesicle size, entrapment efficiency, in vitro release study and antibacterial activity. In vivo study of developed formulation was conducted on Swiss albino mice in comparison with solution of plain drug and a marketed formulation of benzoyl peroxide. It was evident that niosomes are novel carrier for delivery of naturally occurring antimicrobial agents, in deeper tissues of skin. The results showed that drug-loaded niosomes dispersed in the gelling agent are an effective delivery system for treatment of acne vulgaris.
Keywords: Acne vulgaris; Propionibacterium acne; Staphyllococus aureus; anti-inflammatory; antibacterial; rosmarinic acid.