Purification and stabilization of 99mTc-d,l-HMPAO: role of organic extractants.
99mTc-d,l-HMPAO, an important SPECT agent for imaging cerebral perfusion, suffers from the disadvantage of an inherent instability and its shelf life has been reported to be 30 min. The latter is a harsh constraint and not compatible with Centralized Radiopharmacy procedures. During the attempts to improve upon the stability of 99mTc-d,l-HMPAO, preservation of product as an organic extract into suitable solvents like diethylether, ethylacetate, methylethylketone, chloroform was tried out. Chloroform extraction (yield: >90%) resulted in a product having stability not less than 5 hours. Gentle drying of the chloroform extract and reconstitution in normal saline resulted in quantitative recovery of 99mTc-d,l-HMPAO with acceptable radiochemical purity (>90%). This finding is thus of much significance, especially in the context of centralized large hospital radiopharmacy setting, by rendering convenience and flexibility in scheduling patients.
Chattopadhyay
S
S
Radiopharmaceuticals Laboratory, Board of Radiation and Isotope Technology (BRIT), Variable Energy Cyclotron Centre, 1/AF 700 064, Bidhan Nagar, Calcutta, India.
Das
M K
MK
Vanaja
R
R
Ramamoorthy
N
N
D004355:Drug Stability; D009930:Organic Chemicals; D015609:Organotechnetium Compounds / Q000302:isolation & purification*; D010091:Oximes / Q000302:isolation & purification*; D019275:Radiopharmaceuticals / Q000302:isolation & purification*; D012997:Solvents; D013237:Stereoisomerism; D019690:Technetium Tc 99m Exametazime
D009930:Organic Chemicals; D015609:Organotechnetium Compounds; D010091:Oximes; D019275:Radiopharmaceuticals; D012997:Solvents; D019690:Technetium Tc 99m Exametazime