title: Photostability of 6-MAM and morphine exposed to controlled UV irradiation in water and methanol solution: HRMS for the characterization of transformation products and comparison with the dry state.
abstract: The UVA and UVB light-induced behaviour of 6-monoacetylmorphine (6-MAM) and morphine, the main metabolites of heroin, was studied in methanol, aqueous solution and in the dry state. UVA and UVB irradiations were performed for different times (radiant energies of 20-300J/cm(2)). UV spectra of irradiated samples were compared with samples kept in the dark. To estimate the extent of photolysis, positive ion electrospray ionization experiments were performed on the irradiated samples by LC-HRMS. Tentative identification of photoproducts was performed on the basis of their elemental formula as calculated by HRMS results. Morphine and 6-MAM demonstrated to be quite stable under UVA light but very sensitive to UVB irradiation. In methanol solutions they undergo a similar pattern, both reaching 90% photodegradation after 100J/cm(2) of UVB, with a slightly faster kinetic for morphine at lower doses. In water, the yields of photodegradation are nearly one third lower than in methanol. In the solid state, the yield of photodegradation is lower than in solution. The structures of some UVB-induced degradation products are proposed. Photoaddition of the solvent and photooxidation seem the main pathways of phototransformation of these molecules. Moreover, both compounds revealed to generate singlet oxygen under UVB exposure.
authors.affiliation: Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Via Marzolo 5, I-35121 Padova, Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Miolo
authors.affiliation: Department of Cardiological, Thoracic and Vascular Sciences, Legal Medicine and Toxicology, University Hospital of Padova, Via Falloppio 50, I-35121 Padova, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Tucci
authors.affiliation: Department of Chemistry, Biology and Biotechnology and Centro di Eccellenza sui Materiali Innovativi Nanostrutturati (CEMIN), University of Perugia, 06100 Perugia, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Mazzoli
authors.affiliation: Department of Cardiological, Thoracic and Vascular Sciences, Legal Medicine and Toxicology, University Hospital of Padova, Via Falloppio 50, I-35121 Padova, Italy.
authors.forename: Santo Davide
authors.initials: SD
authors.lastname: Ferrara
authors.affiliation: Department of Cardiological, Thoracic and Vascular Sciences, Legal Medicine and Toxicology, University Hospital of Padova, Via Falloppio 50, I-35121 Padova, Italy. Electronic address: donata.favretto@unipd.it.
authors.forename: Donata
authors.initials: D
authors.lastname: Favretto
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D003932:Heroin / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D000432:Methanol / Q000737:chemistry; D009020:Morphine / Q000032:analysis / Q000737:chemistry*; D009022:Morphine Derivatives / Q000032:analysis / Q000737:chemistry*; D010782:Photolysis; D026082:Singlet Oxygen / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D009022:Morphine Derivatives; D012997:Solvents; D014867:Water; D026082:Singlet Oxygen; D003932:Heroin; D009020:Morphine; C026979:6-O-monoacetylmorphine; D000432:Methanol
keywords: 6-monoacetylmorphine; Drugs of abuse; HRMS; Morphine; UVA/UVB-photodegradation