title: Investigation on the phototransformation of tadalafil in aqueous media. 6-Epimerization vs. solvent trapping reaction.
abstract: Irradiation of tadalafil at lambda > 290 nm in aqueous solutions leads to 6-epimer and/or water adducts depending on concentration and pH. A rationalization of the results involves the heterolytic cleavage of C6-N5 bond via a well-stabilized zwitterionic intermediate. The drug is stable in the dark except under strongly basic conditions where it undergoes C12a-epimerization.
authors.affiliation: IC-REACH Dipartimento di Chimica Organica e Biochimica, Università Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia 4, I-80126, Napoli, Italy. ftemussi@unina.it
authors.forename: Fabio
authors.initials: F
authors.lastname: Temussi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bassolino
authors.forename: Flavio
authors.initials: F
authors.lastname: Cermola
authors.forename: Marina
authors.initials: M
authors.lastname: DellaGreca
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Iesce
authors.forename: Sara
authors.initials: S
authors.lastname: Montanaro
authors.forename: Lucio
authors.initials: L
authors.lastname: Previtera
authors.forename: Maria
authors.initials: M
authors.lastname: Rubino
mesh_terms: D002243:Carbolines / Q000737:chemistry* / Q000528:radiation effects; D002384:Catalysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D012997:Solvents / Q000737:chemistry*; D013237:Stereoisomerism; D000068581:Tadalafil; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry*
chemical_list: D002243:Carbolines; D012997:Solvents; D014867:Water; D000068581:Tadalafil