title: Spectroscopic and electrochemical studies of cocaine-opioid interactions.
abstract: The drugs of abuse cocaine (C), heroin (H), and morphine (M) have been studied to enable understanding of the occurrence of cocaine-opioid interactions at a molecular level. Electrochemical, Raman, and NMR studies of the free drugs and their mixtures were used to study drug-drug interactions. The results were analyzed using data obtained from quantum-mechanical calculations. For the cocaine-morphine mixture (C-MH), formation of a binary complex was detected; this involved the 3-phenolic group and the heterocyclic oxygen of morphine and the carbonyl oxygen and the methyl protons of cocaine's methyl ester group. NMR studies conducted simultaneously also revealed C-MH binding geometry consistent with theoretical predictions and with electrochemical and vibrational spectroscopy results. These results provide evidence for the occurrence of a cocaine-morphine interaction, both in the solid state and in solution, particularly for the hydrochloride form. A slight interaction, in solution, was also detected by NMR for the cocaine-heroin mixture.
authors.affiliation: Unidade I&D Química-Física Molecular, Universidade de Coimbra, 3001-401, Coimbra, Portugal. jjg@isep.ipp.pt
authors.forename: Jorge M P J
authors.initials: JM
authors.lastname: Garrido
authors.forename: M Paula M
authors.initials: MP
authors.lastname: Marques
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
authors.forename: Tice R A
authors.initials: TR
authors.lastname: Macedo
authors.forename: Ana M
authors.initials: AM
authors.lastname: Oliveira-Brett
authors.forename: Fernanda
authors.initials: F
authors.lastname: Borges
mesh_terms: D000701:Analgesics, Opioid / Q000737:chemistry*; D001665:Binding Sites; D003042:Cocaine / Q000737:chemistry*; D004347:Drug Interactions; D004563:Electrochemistry; D009020:Morphine; D011789:Quantum Theory; D012996:Solutions; D013057:Spectrum Analysis
chemical_list: D000701:Analgesics, Opioid; D012996:Solutions; D009020:Morphine; D003042:Cocaine