UNLABELLED: The SPECT radioligand, 3-quinuclidinyl-4-[123I]iodobenzilate ([123I]IQNB), binds to muscarinic receptors and has generated interest as a potential agent for clinical SPECT. Unfortunately, cumbersome and inefficient radioiodination procedures have limited the practicality of [123I]IQNB SPECT imaging. METHODS: We report a rapid (5 min) and simple radioiodination procedure for preparing [123I]IQNB from a tri-n-butylstannyl precursor in a no-carrier-added reaction that yields high specific activity with radiochemical yield exceeding 60%. The radiochemical purity of the final product exceeds 95%. RESULTS: We have used this procedure to radioiodinate the four stereoisomers of [123I]IQNB. The procedure is highly reliable and reproducible. SPECT studies on a healthy human volunteer at 1, 2, 6 and 24 hr after injection of each of the four stereoisomers reveal expected differences in the kinetic and binding characteristics of the four stereoisomers. (R,S)-[123I]IQNB appears to be the SPECT agent of choice. CONCLUSION: Radioiodination of [123I]IQNB from our tri-n-butylstannyl precursor is simpler, more efficient and less expensive than previous techniques. The potential exists for a "kit" which would be practical in a typical clinical setting.
UNLABELLED: The SPECT radioligand, 3-quinuclidinyl-4-[123I]iodobenzilate ([123I]IQNB), binds to muscarinic receptors and has generated interest as a potential agent for clinical SPECT. Unfortunately, cumbersome and inefficient radioiodination procedures have limited the practicality of [123I]IQNB SPECT imaging. METHODS: We report a rapid (5 min) and simple radioiodination procedure for preparing [123I]IQNB from a tri-n-butylstannyl precursor in a no-carrier-added reaction that yields high specific activity with radiochemical yield exceeding 60%. The radiochemical purity of the final product exceeds 95%. RESULTS: We have used this procedure to radioiodinate the four stereoisomers of [123I]IQNB. The procedure is highly reliable and reproducible. SPECT studies on a healthy human volunteer at 1, 2, 6 and 24 hr after injection of each of the four stereoisomers reveal expected differences in the kinetic and binding characteristics of the four stereoisomers. (R,S)-[123I]IQNB appears to be the SPECT agent of choice. CONCLUSION: Radioiodination of [123I]IQNB from our tri-n-butylstannyl precursor is simpler, more efficient and less expensive than previous techniques. The potential exists for a "kit" which would be practical in a typical clinical setting.
Authors: Sean J Colloby; Ian G McKeith; David J Burn; David J Wyper; John T O'Brien; John-Paul Taylor Journal: Neurology Date: 2016-06-15 Impact factor: 9.910
Authors: Sanjeet Pakrasi; Sean J Colloby; Michael J Firbank; Elaine K Perry; David J Wyper; Jonathan Owens; Ian G McKeith; E David Williams; John T O'Brien Journal: J Neurol Date: 2007-03-14 Impact factor: 4.849