Synthesis, Characterization, Biodistribution and Scintigraphic Evaluation of Technetium-99m (99mTc) Labeled Pazufloxacin (PZN): A Novel Infection Radiotracer

Abstract

In this study tagging of 99m Tc with PZN was examined with regards to different concentration of PZN, stannous chloride, 99m Tc and pH ranges from 5.00-6.00. The suitability of the 99m Tc labeled PZN was assessed in terms of percent radiochemical purity (%RCP) yield in normal saline at concentration value of the stannous chloride as 120 mg, stability in serum (in vitro) at 37°C at different intervals, in vitro up take by live and heat killed E. coli, biodistribution behavior in artificially E. coli (live and heat killed) infected animal model rat and scintigraphic accuracy in artificially E. coli infected animal model rabbit. Maximum %RCP yields of 98.25 ± 0.26% was observed after 30 m of labeling using 2 mg of PZN, 125 μg stannous chloride, 2.5 m Ci sodium pertechnetate and pH 5.3.The labeled PZN showed stable profile in serum at 37°C with a total decay of 16.40 ± 0.18%. The labeled PZN showed 72.55 ± 0.90% maximum bacterial uptake after 90 min in live and in case of heat killed E. coli, no significant uptake was seen. The labeled PZN showed 14.75 ± 0.40% absorption and accumulation in the infected muscle of the rat infected with live E. coli and infected to normal muscle ratio was 6:1. Scintigraphically, it was observed that after few minutes, the activity accumulated in the infected muscle was more than the others sites. The instant investigation substantiated that labeling PZN through this technique as compared to 99m TcV:N~ and 99m Tc(CO)3s howed almost analogous %RCP yield, stability in serum at 37°C, in vitro binding with E. coli, biodistribution profile in animal modal rats and scintigraphic accuracy in animal model rabbit.