Preparation and preliminary biological evaluation of radiogallium-labeled DTPA-amlodipine complex for possible L-type calcium channel imaging

摘要

A DTPA-conjugated amlodipine analog (DTPAAMLO) 3, was prepared for possible voltage gated calcium channel imaging after radiolabeling with Ga-67. [Ga-67]DTPA- AMLO complex was prepared starting [Ga-67] gallium chloride and DTPA-AMLO in 60-90 min at 50-60 degrees C in phosphate buffer. The partition co-efficient and stability of the tracer was determined in final solution (25 degrees C) and presence of human serum (37 degrees C) upto 24 h. The biodistribution of the labeled compound in wild-type rats were determined up to 72 h using organ counting and SPECT. The radiolabled complex was prepard in high radiochemical purity (> 96%, RTLC and > 98% HPLC) and significant specific activity (7-10 GBq/mmol). The logPfor the complex was calculated as -0.594, consistent with a water soluble complex. The tracer is mostly washed out through kidneys which were in full compliance with the amlodipine metabolism and imaging studies demonstrated the same behavior. The tracer uptake in organs with smooth muscles was observed in stomach, colon as well as intestine.