title: Photostabilization of sunscreen oil through preparation of a free-flowing powder.
abstract: Octyl-p-methoxycinnamate (OMC) is a sun-blocking agent that absorbs ultraviolet (UV) radiation in UVB range. However, when exposed to sunlight, OMC is converted into a less UV-absorbent form, which reduces its effectiveness. The aim of this study was to stabilize the oil by microencapsulation and to convert it into a free-flowing powder form. In addition, the study aimed to develop a suitable high-performance liquid chromatography method to detect the oil in the presence of its degradation product. OMC was microencapsulated by the congealable disperse-phase encapsulation using carnauba wax (cw) and beeswax (bw) at different wax-to-drug ratios (2:1 and 4:1). The photostability of the oil was investigated by exposing the microspheres to UV radiation. After 180 min of exposure, the photoprotective abilities of all the tested formulae were similar and reached about 82%. However, physicochemical assessment showed superiority of cw microspheres over their bw analogues.
authors.affiliation: Faculty of Pharmacy, Department of Pharmaceutics, Cairo University, Egypt. latifranda@yahoo.co.uk
authors.forename: Randa
authors.initials: R
authors.lastname: Latif
authors.forename: Hanan
authors.initials: H
authors.lastname: Refai
authors.forename: Shereen
authors.initials: S
authors.lastname: Tawakkol
mesh_terms: D002214:Capsules; D002934:Cinnamates / Q000737:chemistry*; D004355:Drug Stability; D055668:Photochemical Processes / Q000528:radiation effects*; D013473:Sunscreening Agents / Q000737:chemistry*; D013997:Time Factors; D014466:Ultraviolet Rays; D014885:Waxes / Q000737:chemistry
chemical_list: D002214:Capsules; D002934:Cinnamates; D013473:Sunscreening Agents; D014885:Waxes; C038228:beeswax