Copper(II) complexes of a new cynnamyl derivative of the antibiotic rifampicin

Radiosynthesis and biodistribution of (99m)Tc-rifampicin: a novel radiotracer for in-vivo infection imaging

(99m)Tc-rifampicin ((99m)Tc-RMP) a new radioantibiotic complex was synthesized specifically for the infection localization caused by methicillin-resistant Staphylococcus aureus (MRSA). The in-vitro radiochemical purity (RCP) yield, in-vivo biodistribution behavior in artificially infected rats (AIT) and scintigraphic accuracy in artificially infected rabbit (AIB) of the (99m)Tc-RMP complex was investigated using different concentration of the RMP, sodium pertechnetate (Na(99m)TcO(4)), stannous chloride dihydrate (SnCl(2) x 2H(2)O) at different pH ranges 5-6. The best RCP yield observed at 30, 60, 90 and 120 min after labeling was; 98.95+/-0.20, 98.15+/-0.24, 96.50+/-0.27 and 91.55+/-0.22%, respectively, using 1.5 mg RMP, 175 microL of SnCl(2) x 2H(2)O (1 microg/microL in 0.01 N HCl), 3 mCi of Na(99m)TcO(4), at pH 5.6. Initially in the infected muscle (INM) of the AIT the activity was lower but after 90 min it went up to 18.35+/-0.20% from 5.95+/-0.25%. The activity in the inflamed muscle (IMM), normal (NM) muscle, blood, liver and spleen was initially high that decreased with time. The ratios of the INM/NM and IMM/NM were 7.34+/-0.74 and 1.20+/-0.85, respectively. The whole body static (WBS) imaging of the MRSA infected rabbit confirmed the usefulness of the (99m)Tc-RMP as a precise radiotracer for MRSA infection imaging. On the basis of in-vitro RCP, in-vivo biodistribution and scintigraphic precision, we recommend the (99m)Tc-RMP complex prepared aseptically for in-vivo assessment of MRSA infection.

Spectroscopic studies on the anticancer antibiotic Altromycin H and the interaction with copper(II) ions

The antitumor antibiotic Altromycin H was studied using electronic absorption (UV-Vis.) and circular dichroism (CD) spectroscopy. The dissociation constants of the phenolic groups on C(5) and C(11) were estimated as pK(1)=6.7 and pK(2)=11.8 at 25 degrees C, respectively, and a complete assignment of the CD and UV-Vis. bands is proposed. The interaction of Cu(II) ions with the Altromycin H has been also investigated by UV-Vis., CD and electron paramagnetic resonance (EPR) spectroscopy. A pH depended stepwise complex formation was observed. At pH<4 no copper-Altromycin H interactions were detected. At the 4<pH<8 the Cu(II) ions coordinate to Altromycin H via the C(4)O and C(5)OH groups atoms of the chromophore ring and the [Cu(AltroH)(2)] complex (formation constant, K(f), 4.00+/-0.9 x 10(11) M(-2) at 25 degrees C) is the predominant species. In alkaline solution the hydroxo-bridged complex, [Cu(OH)(AltroH)](2), is proposed to be as the unique present species.