Optimization condition in labeling of ofloxacin with [99m]Tc and its biological evaluation in Staphylococcus aureus and Escherichia coli for infection imaging

The use of radiopharmaceuticals is a powerful tool in the management of patients with infectious or inflammatory diseases in nuclear medicine. In this study ofloxacin as a second-generation fluoroquinolone is used to design a desired infection imaging agent after labeling with [99m]Tc via direct labeling. Ofloxacin was radiolabeled with [99m]Tc using different concentrations of ligand, stannous chloride, sodium pertechnetate and at different pH. Then labeling yield, stability in saline and serum, lipophilicity, binding with Staphylococcus aureus and Escherichia coli and biodistribution in infected mice for labeled compound were studied. The final complex was characterized by TLC and HPLC and radiochemical purity of >90% was obtained when 1.5 mg ofloxacin in presence of 75 micro g SnCl2 was labeled with 370 MBq sodium pertechnetate. The complex showed specific binding to Staphylococcus aureus and Escherichia coli. Biodistribution results showed that radioligand had high affinity in the infected site in mice. The uptake for Staphylococcus aureus induced infections [T/NT = 2.33 +/- 0.17 at 1 h post injection] was higher than that was for Escherichia coli [T/NT = 1.96 +/- 0.13 at 1 h post injection]. This complex may lead to further development of a radiotracer for imaging of infections induced by grampositive or gram-negative bacteria

effect of prednisolone on the sensitivity of Technetium 99m-methylene diphosphonate [[99m] Tc-MDP] scintigraphy to detect simulated closed fracture in the rat tibia

The purpose of the present study was to evaluate the effect of prednisolone on the sensitivity of bone scanning to detect the simulated closed fracture in the rat tibia. A total number of forty eight adult, male NMRI rats randomly assigned into two parts, one part for 4 and other for 8 weeks experiments. Each part has been divided into four groups, one group not receiving prednisolone [control group] and the other groups receiving 5, 10 and 20 mg/kg prednisolone respectively. After four and eight weeks of experiments a simulated closed fracture was created in the tibia approximately 1 cm near knee joint. .The scintigraphy imaging has been performed on second and fifth day after tibial bone fracture and the ratio of the activity of tibia bone fracture to the contra lateral healthy side was calculated [R factor]. All scintigraphy images showed the rat tibia bone fracture. Statistically significant difference in the R factors have been observed, when scintigraphy images were performed in fifth day after injury. Bone radionuclide scanning by [99m]Tc-MDP is very sensitive for detection of occult fracture. In order to enhance bone scan sensitivity, it may be reasonable to postpone [99m]Tc-MDP scintigraphy imaging at least 2 to 3 days after suspected trauma in patients receiving glucocorticoid medication