title: Enhancement of melatonin photostability by encapsulation in lipospheres.
abstract: The effect of lipid microparticle carrier systems on the light-induced degradation of melatonin was investigated. Microspheres loaded with melatonin were prepared using tristearin or tripalmitin as the lipid material and hydrogenated phosphatidylcholine or polysorbate 60 as the emulsifier. The obtained lipid microspheres were characterized by scanning-electron microscopy and differential scanning calorimetry. Free or microencapsulated melatonin was incorporated in a model cream formulation (oil-in-water emulsion) and irradiated with a solar simulator. The extent of photodegradation was measured by high-performance liquid chromatography. The photolysis experiments demonstrated that the light-induced decomposition of melatonin was markedly decreased by encapsulation into lipid microspheres based on tristearin and phosphatidylcholine (the extent of degradation was 19.6% for unencapsulated melatonin compared to 5.6% for the melatonin-loaded microparticles). Therefore, incorporation in lipid microparticles can be considered an effective system to enhance the photostability of melatonin.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Università di Ferrara, via Fossato di Mortara 17, 44100 Ferrara, Italy.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Tursilli
authors.forename: Alberto
authors.initials: A
authors.lastname: Casolari
authors.forename: Valentina
authors.initials: V
authors.lastname: Iannuccelli
authors.forename: Santo
authors.initials: S
authors.lastname: Scalia
mesh_terms: D003692:Delayed-Action Preparations; D004339:Drug Compounding; D004355:Drug Stability; D045703:Emulsifying Agents / Q000737:chemistry; D004655:Emulsions; D008027:Light; D008081:Liposomes / Q000737:chemistry*; D008550:Melatonin / Q000737:chemistry* / Q000528:radiation effects; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry; D010782:Photolysis; D012995:Solubility; D013499:Surface Properties; D014280:Triglycerides / Q000737:chemistry*
chemical_list: D003692:Delayed-Action Preparations; D045703:Emulsifying Agents; D004655:Emulsions; D008081:Liposomes; D010713:Phosphatidylcholines; D014280:Triglycerides; D008550:Melatonin; C022618:tristearin