Natural products used in the treatment of acne vulgaris may be promising alternative therapies with fewer side effects and without antibiotic resistance. The objective of this study was to formulate creams containing Spirulina (Arthrospira) platensis to be used in acne therapy. Spirulina platensis belongs to the group of micro algae and contains valuable active ingredients. The aim was to select the appropriate nonionic surfactants for the formulations in order to enhance the diffusion of the active substance and to certify the antioxidant and antibacterial activity of Spirulina platensis-containing creams. Lyophilized Spirulina platensis powder (SPP) was dissolved in Transcutol HP (TC) and different types of nonionic surfactants (Polysorbate 60 (P60), Cremophor A6:A25 (CR) (1:1), Tefose 63 (TFS), or sucrose ester SP 70 (SP70)) were incorporated in creams as emulsifying agents. The drug release was evaluated by the Franz diffusion method and biocompatibility was tested on HaCaT cells. In vitro antioxidant assays were also performed, and superoxide dismutase (SOD) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were executed. Antimicrobial activities of the selected compositions were checked against Staphylococcus aureus (S. aureus) and Cutibacteriumacnes (C. acnes) (formerly Propionibacterium acnes) with the broth microdilution method. Formulations containing SP 70 surfactant with TC showed the most favorable dissolution profiles and were found to be nontoxic. This composition also showed significant increase in free radical scavenger activity compared to the blank sample and the highest SOD enzyme activity was also detected after treatment with the cream samples. In antibacterial studies, significant differences were observed between the treated and control groups after an incubation time of 6 h.
Keywords: Spirulina platensis; UVB-induced oxidative stress; acne vulgaris; antimicrobial; antioxidant; cutibacterium acnes; nonionic surfactants; topical formulations; transcutol.