Tc-HMPAO Hexamethylpropylene Amine Oxime

8-diaza-3,6,6,9-tetramethyl-undecane-2,10-dione-bisoxime (HMPAO) 

The Ceretec kit contains the lyophilized, sterile ingredients in a multidose vial. Labeling with Tc eluate is carried out under aseptic conditions by adding 5 ml of sterile sodium Tc-pertechnetate to the vial (0.37-1.11 GBq). The shielded vial should be gently inverted for 10 s to ensure complete dissolution of the lyophilisate. The reaction is allowed to proceed at room temperature for 5 min. 

In addition, each package consisting of five labeling units contains also five vials of methylene blue injection 1% USP (10 mg methylene blue USP in 1 ml water for injection), and five vials containing 0.003 M monobasic sodium phosphate USP and dibasic sodium phosphate USP in 4.5 ml of 0.9% sodium chloride injection USP. Each milliliter contains 0.276 mg monobasic sodium phosphate monohydrate, 0.142 mg dibasic sodium phosphate anhydrous, and 9 mg sodium chloride in water for injection for a sufficient amount. A mixture of methylene blue in phosphate buffer is used for stabilization of the Tc-HMPAO complex (Amersham Healthcare 1995). 

99rnTc-exametazime injection solution should be used within 60 min after labeling. In order to maintain high stability of the Tc-HMPAO complex for up to 6 h after preparation, the producer provides methylene blue injection USP 1% or alternatively, cobalt(II)-chloride aqueous solution (250 pg/2.5 ml, European Pharmacopeia [Ph. Eur.]) for stabilization. 

Stabilization of the Tc-HMPAO complex for intravenous use with methylene blue. Half a milliliter of methylene blue injection 1% USP should be withdrawn into a sterile syringe and injected into the 4.5-ml vial containing the buffer solution. Two milliliters of the methylene blue/phosphate buffer mixture should be gently swirled and withdrawn into a syringe for use as stabilizer. This mixture must be used within 30 min of preparation. 

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