Stability of the mixture of technetium-99m human serum albumin and lidocaine hydrochloride for clinical application.Nucl Med Commun. 2009 Jul; 30(7):494-7.NM
To evaluate the stability of the mixture of technetium-99m (99mTc) human serum albumin (HSA) with the local anesthetic lidocaine hydrochloride.
MATERIALS AND METHODS
We assessed three preparations of the radiotracer, 99mTc-HSA, filtered 99mTc-HSA, and a mixture of 99mTc-HSA with lidocaine hydrochloride and then filtered. Time sequence evaluation was performed on all the specimens (n= 10) at 0, 30, 60, 90, 120, 150, and 180 min after preparation. Measurements of radiochemical purity as labeling stability and pH value change were conducted for each group of specimens.
We found no definite difference in the stability before and after the filtering procedure for 99mTc-HSA. However, we showed a decline of stability in the mixture of 99mTc-HSA with lidocaine. The filtered specimens showed a relatively higher pH value, towards a more neutral status, as compared with the unfiltered specimens.
Though pain relief for the patient receiving sentinel lymph node mapping is important, a preparation of a mixture of 99mTc-HSA and lidocaine may cause radiolabeling instability. Furthermore, compared with the filtered 99mTc-sulfur colloid, a filtering procedure does not change the labeling stability of the 99mTc-HSA. On the contrary, the filtered preparation was neutralized closer to the physiologic condition. For lymphoscintigraphic studies,our results suggested that pretreatment with local anesthesia followed by subdermal injection of a filtered 99mTc-HSA rather than a pre-mixture with lidocaine is appropriate for clinical application.