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.

Morphine studied by vibrational spectroscopy and DFT calculations

“…[12] Beside this fact, the spectral pattern of both salts is similar and shows very clearly characteristic bands of morphine. These results are in agreement with the previously reported data for morphine [10] and morphine hydrochloride [7] registered with laser excitation at 785 and 514 nm, respectively.…”

“…The CG structure in which hydroxyl groups' arrangement allows for the formation of two intramolecular H-bonds (O 18 H 31 · · ·O 40 = 2.129 Å and O 19 H 32 · · ·O 40 = 2.485 Å) is the gas-phase, energetically preferred form predicted by calculations. The obtained results are in some contradiction to those of Garrido et al, [7] where a geometry of N-protonated morphine with terminal groups pointing outside in opposite directions was considered. Our computations show that arrangement of the hydroxyl groups in respect to the rings has a considerable impact on the infrared signature of the compound.…”

“…[6] The structural analysis of morphine and analysis of its vibrational spectra were performed at the B3LYP/6-31G(d) level. [7] SERS, FT-IR and Raman spectroscopy, assisted by density functional theory (DFT) computational methods, were employed to investigate the absorption and orientation of morphine on a silver surface. [8 -10] The results suggested that the molecule had a charge-transfer adsorption on the Ag island film, and both planes of its 'T' type structure had a rather perpendicular orientation to the substrate, mainly via the lone-pair electrons on the oxygen atoms.…”

Carbon nanotube β-cyclodextrin-modified electrode for quantification of cocaine in seized street samples

“…The mechanism postulated for the oxidation of tertiary amines involves abstraction of an electron from the amino-nitrogen, followed by a rapid proton loss to form a neutral radical, which then loses an electron and is hydrolysed to the products. The oxidation reaction leads to a secondary amine, norcocaine (Scheme 2), and an aldehyde [26][27][28].…”

Heroin-related overdose: The unexplored influences of markets, marketing and source-types in the United States

“…Much less is understood about the pharmacodynamics of this mixture than about that of either drug on its own. Animal studies suggest that the effect of heroin and cocaine in combination is unique and different from either drug alone, (Garrido et al, 2007) with increased neurotoxicity compared with heroin and cocaine used sequentially (Cunha-Oliveira et al, 2010). Epidemiological findings suggest that speedballs may play a role in heroin overdose risk but this is less well established than that of sedatives (O’Driscoll et al, 2001).…”