title: Usnea barbata CO2-supercritical extract in alkyl polyglucoside-based emulsion system: contribution of Confocal Raman imaging to the formulation development of a natural product.
abstract: Topical treatment of skin infections is often limited by drawbacks related to both antimicrobial agents and their vehicles. In addition, considering the growing promotion of natural therapeutic products, our objective was to develop and evaluate naturally-based emulsion system, as prospective topical formulation for skin infections-treatment. Therefore, alkyl polyglucoside surfactants were used for stabilization of a vehicle serving as potential carrier for supercritical CO2-extract of Usnea barbata, lichen with well-documented antimicrobial activity, incorporated using two protocols and three concentrations. Comprehensive physicochemical characterization suggested possible involvement of extract's particles in stabilization of the investigated system. Raman spectral imaging served as the key method in disclosing extract's particles potential to participate in the microstructure of the tested emulsion system via three mechanisms: (1) particle-particle aggregation, (2) adsorption at the oil-water interface and (3) hydrophobic particle-surfactant interactions. Stated extract-vehicle interaction proved to be correlated to the preparation procedure and extract concentration on one hand and to affect the physicochemical and biopharmaceutical features of investigated system, on the other hand. Thereafter, formulation with the best preliminary stability and liberation profile was selected for further efficiency and in vivo skin irritation potential evaluation, implying pertinent in vitro antimicrobial activity against G+ bacteria and overall satisfying preliminary safety profile.
authors.affiliation: a Department of Pharmaceutical Research and Development , Institute for Medicinal Plant Research "Dr Josif Pancic" , Belgrade , Serbia .
authors.forename: Ana
authors.initials: A
authors.lastname: Zugic
authors.affiliation: b Department of Pharmaceutical Technology , Eberhard-Karls Universität , Tübingen , Germany .
authors.forename: Dominique Jasmin
authors.initials: DJ
authors.lastname: Lunter
authors.affiliation: b Department of Pharmaceutical Technology , Eberhard-Karls Universität , Tübingen , Germany .
authors.forename: Rolf
authors.initials: R
authors.lastname: Daniels
authors.affiliation: c Department of Pharmaceutical Technology and Cosmetology, Faculty of Pharmacy , University of Belgrade , Belgrade , Serbia .
authors.forename: Ivana
authors.initials: I
authors.lastname: Pantelic
authors.affiliation: d Department of Pharmacy, Faculty of Medicine , University of Nis , Nis , Serbia , and.
authors.forename: Marija
authors.initials: M
authors.lastname: Tasic Kostov
authors.affiliation: a Department of Pharmaceutical Research and Development , Institute for Medicinal Plant Research "Dr Josif Pancic" , Belgrade , Serbia .
authors.forename: Vanja
authors.initials: V
authors.lastname: Tadic
authors.affiliation: e Department of Microbiology, Faculty of Veterinary Medicine , University of Belgrade , Belgrade , Serbia.
authors.forename: Dusan
authors.initials: D
authors.lastname: Misic
authors.affiliation: d Department of Pharmacy, Faculty of Medicine , University of Nis , Nis , Serbia , and.
authors.forename: Ivana
authors.initials: I
authors.lastname: Arsic
authors.affiliation: c Department of Pharmaceutical Technology and Cosmetology, Faculty of Pharmacy , University of Belgrade , Belgrade , Serbia .
authors.forename: Snezana
authors.initials: S
authors.lastname: Savic
mesh_terms: D001688:Biological Products / Q000032:analysis* / Q000494:pharmacology; D002245:Carbon Dioxide / Q000737:chemistry; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D045703:Emulsifying Agents / Q000032:analysis* / Q000494:pharmacology; D005960:Glucosides / Q000032:analysis* / Q000494:pharmacology; D006801:Humans; D009924:Organ Culture Techniques; D012869:Skin Absorption / Q000187:drug effects / Q000502:physiology; D013059:Spectrum Analysis, Raman / Q000379:methods*; D020949:Usnea; D055815:Young Adult
chemical_list: D001688:Biological Products; D045703:Emulsifying Agents; D005960:Glucosides; D002245:Carbon Dioxide
keywords: Antimicrobial activity; biopharmaceutical characterization; colloidal structure; extract–vehicle interaction; physicochemical stability; skin performance