Physicochemical Properties and Anti-Propionibacterium acnes Activity of Film-Forming Solutions Containing Alpha-Mangostin-Rich Extract

The objective of this study was to study the effect of formulation compositions on physicochemical properties and anti-Propionibacterium acnes activity of film-forming solutions containing alpha-mangostin-rich extract (AM). Film-forming solution bases and film-forming solutions containing AM were prepared by using Eudragit RL PO or Klucel LF or combinations of them as film-forming polymers. Rheological properties, pH values of the solutions, and mechanical properties of the dry films were investigated. An optimized formulation was selected and evaluated for the film surface, in vitro AM release, an anti-P. acnes activity, and potential for being a skin irritant. It was found that mechanical properties of the dry films were affected by total polymer contents, ratios of Klucel LF/Eudragit RL PO, AM, and contents of triethyl citrate. The film-forming solutions containing AM had pH values around 7.0. Their flow curves exhibited Newtonian flow behaviors. The optimized formulation provided films possessing smooth and nonporous surfaces. These films showed greater anti-P. acnes activity than their base films without toxicity to skin fibroblasts. Furthermore, AM released from the film matrix obeyed Higuchi's equation. In conclusion, the film-forming solutions containing AM had potential for treatment of acne vulgaris caused by P. acnes. However, further in vivo study is necessary to determine their efficacy and safety for using in patients suffering from acne vulgaris.