title: Stabilization of [99mTc]HMPAO--1. Ethanolic preparation.
abstract: The use of [99mTc]HMPAO for cerebral blood flow imaging has been hampered by the short useful life time of the labelled radiopharmaceutical. Preparation of [99mTc]HMPAO in 85% ethanol was found to increase the in vitro stability (92% radiochemical purity at 90 min) in comparison to the aqueous preparation (79% at 90 min). Biological distribution studies in mice indicated similar brain uptake (4.42 +/- 1.02 and 4.12 +/- 0.82% per gram at 20 min) and brain: blood ratio (0.97 +/- 0.27 and 1.03 +/- 0.20 at 20 min) of the ethanolic (2 h after preparation) and aqueous (15 min after preparation) formulations of [99mTc]HMPAO respectively. The improved in vitro stability of [99mTc]HMPAO prepared in 85% ethanol may prove useful in instances where previously the 30 min time limit precluded its use.
authors.affiliation: Health Sciences Centre, Winnipeg, Manitoba, Canada.
authors.forename: M W
authors.initials: MW
authors.lastname: Billinghurst
authors.forename: D N
authors.initials: DN
authors.lastname: Abrams
authors.forename: M S
authors.initials: MS
authors.lastname: Lawson
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D000431:Ethanol; D005079:Excipients; D051379:Mice; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010091:Oximes / Q000493:pharmacokinetics; D019690:Technetium Tc 99m Exametazime; D014018:Tissue Distribution; D014867:Water
chemical_list: D005079:Excipients; D015609:Organotechnetium Compounds; D010091:Oximes; D014867:Water; D019690:Technetium Tc 99m Exametazime; D000431:Ethanol