Abstract
Objective: The package insert for Neurolite® suggests a radiochemical purity (RCP) value of greater than 90% and a procedure for the RCP determination that uses a thin-layer chromatography (TLC) plate and a solvent system of ethyl acetate. This technique is very time-consuming, taking approximately 40 to 60 min to complete.
Methods: A new, convenient mini-paper chromatography (MPC) method has been developed for the RCP analysis of 99mTc-bicisate that utilizes precut (1.0 cm x 9.0 cm) Whatman Chr 17 paper as the stationary phase and ethyl acetate as the mobile phase. A blood collection tube (16 cm x 100 cm) was used as the developing chamber and did not require the pre-equilibration step for solvent saturation.
Results: Ten sets of triplicate measurements were obtained over a range of 72.1 %-98.3%. Technetium-99m-bicisate had an R1 value of 0.8–1.0 in the proposed MPC method and this new method decreased the RCP analysis to 3—4 min. The recommended TLC method and the proposed MPC method correlate very closely with r = 0.9987 and a linear regression of TLC% = 0.96 MPC% + 3.63%. Overall the MPC method underestimates the RCP values obtained by the TLC method so that using the MPC’s RCP values (without converting via the regression equation) leads to a conservative procedure. A 99mTc-bicisate kit may be rejected by the MPC method yet may pass with the TLC method. Therefore the MPC method will not create a false positive RCP result.
Conclusion: The MPC method provides a rapid and efficient RCP analysis of 99mTc-bicisate.
