Aim. Technetium-99m-d,l-hexameththylpropyleneamineoxime (99mTc-d,l-HMPAO) prepared from the commercially available lyophilized kit , Ceretec™, (GE Healthcare, UK) is used to image regional cerebral blood flow and for in vitro leukocytes labeling. The aim of this work was to study the influence of the nature (pH, plastic ampoules stored away from light sources or glass ampoules) of 0,9% NaCl sodium chloride injection used to dilute generator produced sodium pertechnetate at 1, 2 , 5 mL for the Ceretec™ reconstitution on the radiochemical purity and stability of 99mTc-d,l-HMPAO. Materials and methods. 99mTc-d,l-HMPAO is prepared using commercially available freeze-dried kits according to the procedure specified by the manufacturer. Kits were reconstituted with 1, 2 or 5 mL of fresh (not more 2 h old) generator eluted sodium [99mTc]pertechnetate coming from a generator eluted not more than 24 h in 0,9% NaCl containing 0,074-0,22 GBq/mL. The radioactive concentration was obtained by diluting generator eluted sodium [99mTc]pertechnetate with 0,9% NaCl Sodium Chloride Injection coming from stored away from light sources plastic ampoules and Sodium Chloride Injection from glass ampoules. The radiochemical purity was measured at 0, 15 and 30 min after preparation and was determined by methods specified by the manufacture. Results. We found no influence on the radiochemical purity and stability ( at 30 min following the preparation) of 99mTc-HMPAO based on the type and the pH of sodium chloride injection used for pertechnetate diluting. RCP values decreased proportionally with the decrease of the final volume of preparation and in particular for 1 mL of diluted pertechnetate, the PCR at 30 minutes following the preparation is less than the required (80%). Finally we found that pH average for 99mTc-d,l-HMPAO is lower than indicated by the manufacturer (9,0-9,8). Conclusions. In summary in this work we found that instability of the neutral lipophilic 99mTc-d,l-HMPAO complex is faster in reconstituted kits with smaller volumes than 2 mL of pertechnetate, as happens in routine preparations for in vitro leukocyte labeling, and in particular reconstituted kit with volume of 1 mL can’t be used beyond the 15 minutes of preparation. This suggests that any protocols that provide volumes smaller than 2 mL of pertechnetate for the Ceretec™ reconstitution should be carefully evaluated in terms of stability of the product. We also noted that the pH average for any categories of preparation is lower than indicated by the manufacturer (9,0-9,8). This does not seem to compromise the stability of the product.

Radiochemical Puritiy Of 99mTc-HMPAO: some Considerations on Routine Radiopharmaceuticals Preparation

PASQUALI, Micol;UCCELLI, Licia;BOSCHI, Alessandra;GIGANTI, Melchiore;DUATTI, Adriano
2012

Abstract

Aim. Technetium-99m-d,l-hexameththylpropyleneamineoxime (99mTc-d,l-HMPAO) prepared from the commercially available lyophilized kit , Ceretec™, (GE Healthcare, UK) is used to image regional cerebral blood flow and for in vitro leukocytes labeling. The aim of this work was to study the influence of the nature (pH, plastic ampoules stored away from light sources or glass ampoules) of 0,9% NaCl sodium chloride injection used to dilute generator produced sodium pertechnetate at 1, 2 , 5 mL for the Ceretec™ reconstitution on the radiochemical purity and stability of 99mTc-d,l-HMPAO. Materials and methods. 99mTc-d,l-HMPAO is prepared using commercially available freeze-dried kits according to the procedure specified by the manufacturer. Kits were reconstituted with 1, 2 or 5 mL of fresh (not more 2 h old) generator eluted sodium [99mTc]pertechnetate coming from a generator eluted not more than 24 h in 0,9% NaCl containing 0,074-0,22 GBq/mL. The radioactive concentration was obtained by diluting generator eluted sodium [99mTc]pertechnetate with 0,9% NaCl Sodium Chloride Injection coming from stored away from light sources plastic ampoules and Sodium Chloride Injection from glass ampoules. The radiochemical purity was measured at 0, 15 and 30 min after preparation and was determined by methods specified by the manufacture. Results. We found no influence on the radiochemical purity and stability ( at 30 min following the preparation) of 99mTc-HMPAO based on the type and the pH of sodium chloride injection used for pertechnetate diluting. RCP values decreased proportionally with the decrease of the final volume of preparation and in particular for 1 mL of diluted pertechnetate, the PCR at 30 minutes following the preparation is less than the required (80%). Finally we found that pH average for 99mTc-d,l-HMPAO is lower than indicated by the manufacturer (9,0-9,8). Conclusions. In summary in this work we found that instability of the neutral lipophilic 99mTc-d,l-HMPAO complex is faster in reconstituted kits with smaller volumes than 2 mL of pertechnetate, as happens in routine preparations for in vitro leukocyte labeling, and in particular reconstituted kit with volume of 1 mL can’t be used beyond the 15 minutes of preparation. This suggests that any protocols that provide volumes smaller than 2 mL of pertechnetate for the Ceretec™ reconstitution should be carefully evaluated in terms of stability of the product. We also noted that the pH average for any categories of preparation is lower than indicated by the manufacturer (9,0-9,8). This does not seem to compromise the stability of the product.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1732147
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