Muhammad Rafiullah Khan

Radiosynthesis and biodistribution of 99mTc-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.

Radiosynthesis and biological evaluation of the 99mTc-tricarbonyl moxifloxacin dithiocarbamate complex as a potential Staphylococcus aureus infection radiotracer

In the present investigation, radiosynthesis of the (99m)Tc-tricarbonyl moxifloxacin dithiocarbamate complex ((99m)Tc(CO)(3)-MXND) and its biological evaluation in male Wister rats (MWR) artificially infected with Staphylococcus aureus (S. aureus) was assessed. The (99m)Tc(CO)(3)-MXND complex was radiochemically examined in terms of stability in saline and in serum and biologically its in-vitro binding with S. aureus and percent absorption in MWR models. Radiochemically the (99m)Tc(CO)(3)-MXND complex showed more than 90% stability in saline up to 240 min and in serum 14.95% undesirable species was appeared within 16h. In-vitro the (99m)Tc(CO)(3)-MXND complex showed saturated binding with S. aureus. In MWR artificially infected with live S. aureus the complex showed about six fold higher uptakes in the infected muscle as compared to the normal muscle. However, insignificant change in the uptake of (99m)Tc(CO)(3)-MXND complex in the infected and inflamed or normal muscle was observed in the MWR infected with heat killed S. aureus. The (99m)Tc(CO)(3)-MXND complex disappeared from the circulatory system and appeared in the urinary system within 60-90 min followed by excretion through normal route of urinary system. Based on the elevated and stable radiochemical succumb in saline, serum, saturated in-vitro binding with S. aureus and higher accumulation in the target organ of the MWR, we recommend the (99m)Tc(CO)(3)-MXND complex for radio-localization of the infection induced by S. aureus in human.

Synthesis and Biological Evaluation of the 99mtcn-Gemifloxacin Dithiocarbamate Complex: A Novel Streptococcus Pneumoniae Infection Imaging Agent

Synthesis and biological evaluation of the 99mTcN-Gemifloxacin dithiocarbamate (99mTcN-GIND) complex was investigated in terms of radiochemical stability (RCP) in saline, serum, in-vitro binding with Streptococcus pneumoniae (S. pneumoniae) and biodistribution in male Wistar rats artificially infected with living and heat killed S. pneumoniae. The maximum RCP was 98.25 ± 0.30% at 30 min and decreased to 91.25 ± 0.34% within 240 min. The complex showed stable behavior (in-vitro) in serum at 37°C with a 14.35% undesirable side products within 16 h. The complex showed 71.25% in-vitro binding S. pneumoniae. The uptake of the complex in the infected muscle was six times higher than the inflamed and normal muscles of the MWR infected with living S. pneumoniae. The promising (in-vitro and in-vivo) radiochemical and biological behavior posed the 99mTcN-GIND complex as a potential radiotracer for S. pneumoniae infection.