Cobalt(III)- and rhodium(III)-porphyrin complexes for the effective degradation of fentanyl: Biological inactivation and mechanistic insights.

Cobalt(III) and rhodium(III) complexes containing the water-soluble porphyrin ligand meso-tri(4-sulfonatophenyl)mono(4-carboxyphenyl)porphine (C1S3TPP), [Rh(C1S3TPP)]Nax•nH2O (1) and [Co(C1S3TPP)]Nax•nH2O (2) were prepared from the direct reaction of free porphyrin and metal chloride salts in refluxing MeOH/DMF or EtOH/H2O. Compounds 1 and 2 were characterized using UV-vis and 1H NMR spectroscopies, and high-resolution mass spectrometry. Cell culture based assays of opioid receptor activation showed that while the rhodium complex reduced fentanyl opioid activity 113-fold to an IC50 value of 1.7 µM, the cobalt complex reduced fentanyl activity by 160-fold to an IC50 value of 2.4 µM. An oxidative mechanism for fentanyl breakdown is proposed.

Poly(butyl cyanoacrylate) nanoparticle containing an organic photoCORM.

Carbon monoxide (CO) is a gasotransmitter, which has shown therapeutic effects in recent studies. Photo carbon monoxide releasing molecules (PhotoCORMs) allow the delivery of CO to be controlled by light. In this work, a new organic photoCORM DK4 is studied. DK4 is a diketone type photoCORM, which releases two CO molecules under visible light and simultaneously generates a fluorescent anthracene derivative. However, this type of CORM suffers from a deactivating hydration reaction and often needs to be incorporated in polymers or micelles. The two highly hydrophobic tert-butyl groups of DK4 protect it from the hydration reaction. DK4 functions in 1% DMSO aqueous solution, in which other DKs are deactivated. DK4 was incorporated in a poly(butyl cyanoacrylate) (PBCA) nanoparticle. PBCA has been used as a tissue adhesive and has been extensively studied for delivery of drugs to the brain. The PBCA/DK4 nanoparticle showed good photoactivity and low cytotoxicity, and thus is a promising material for studying the biomedical effects of CO.

Non-photochemical catalytic hydrolysis of methyl parathion using core-shell Ag@TiO2 nanoparticles.

Highly water-dispersible core-shell Ag@TiO2 nanoparticles were prepared and shown to be catalytically active for the rapid degradation of the organothiophosphate pesticide methyl parathion (MeP). Formation of the hydrolysis product, p-nitrophenolate was monitored at pH 7.5 and 8.0, using UV-Vis spectroscopy. 31P NMR spectroscopy confirmed that hydrolysis is the predominant pathway for substrate breakdown under non-photocatalytic conditions. We have demonstrated that the unique combination of TiO2 with silver nanoparticles is required for catalytic hydrolysis with good recyclability. This work represents the first example of MeP degradation using TiO2 doped with AgNPs under mild and ambient conditions. Analysis of catalytic data and a proposed dark mechanism for MeP hydrolysis using core-shell Ag@TiO2 nanoparticles are described.