Search

Schizophrenia is a devastating mental disorder characterized by relapsing psychotic episodes accompanied with emotional, professional and social decline. The classical dopamine hypothesis of schizophrenia postulates that hyperactivity of dopaminergic neurotransmission is responsible for the positive symptoms of the disorder. More exactly hyperactivity of the dopamine D3 receptor system is thought to be involved in the pathology of schizophrenia. Therefore, a new ¹²³I-labelled compound was developed which may allow in vivo visualization of the D3 receptor by SPECT. [¹²³I]-4-iodo-N-(4-(4-(2-methoxyphenyl)-piperazin-1-yl)butyl)-benzamide was synthesized and labelled by electrophilic aromatic substitution of the tributylstannyl derrivative. The radiochemical yield was 82–85% and the specific activity was >2.96 Ci/µmol. Copyright © 2003 John Wiley & Sons, Ltd.

Schizophrenia is a devastating mental disorder characterized by relapsing psychotic episodes accompanied with emotional, professional and social decline. The classical dopamine hypothesis of schizophrenia postulates that hyperactivity of dopaminergic neurotransmission is responsible for the positive symptoms of the disorder. More exactly hyperactivity of the dopamine D3 receptor system is thought to be involved in the pathology of schizophrenia. Therefore a new ¹²³I-labelled compound was developed which may allow in vivo visualization of the D3 receptor by SPECT. [¹²³I]-4-iodo-N-(4-(4-(2-methoxyphenyl)-piperazin-1-yl)butyl)-benzamide was synthesized and labelled by electrophilic aromatic substitution of the tributylstannyl derrivative. The radiochemical yield was 82–85% and the specific activity was >2.96 Ci/µmol. Copyright © 2003 John Wiley & Sons, Ltd.

4-[¹²³I]Iodo-N-{2-[4-(6-trifluoromethyl-2-pyridinyl)-1-piperazinyl]ethyl}benzamide (1. ¹²³I), a potential SPECT 5-HT1A radioligand, was synthesized by electrophilic iododestannylation of the tributyltin derivative with n.c.a. [¹²³I]NaI and chloramine-T under acidic conditions (20 min, ambient temperature). Radiochemical yield averaged around 60 % (sd = 8,n = 22). After HPLC purification, chemical purity was higher than 95 % and radiochemical purity higher than 99 %. Specific activity was always higher than 222 GBq/µmol (6 Ci/µmol). The calculated log P is 4.28. Initial brain uptake in NMRI mice was 1.16 % ID (2 min) and decreased slowly afterwards (0.51 % ID (2 h)). 60 min p.i., the majority of the radioactivity in plasma and brain was present as 1. ¹²³I, respectively 75.15 % and 96.48 %. Copyright © 2001 John Wiley & Sons, Ltd.

The synthesis of two ¹¹C labelled chromeno[3,4-c]pyridin-5-ones for the visualisation of the dopamine D4 receptor subtype has been developed. The production entailed an O-methylation of the O-desmethyl precursor with [¹¹C]iodomethane in the presence of tetrabutylammonium hydroxide. Subsequent purification by RP-HPLC and formulation by tracer enrichment on a C18 Sep Pak provided a solution which was suitable for human iv injection. Specific activity of the tracer averaged 37 GBq/μmol at EOS and the radiochemical yields were 65% (decay-corrected, based on [¹¹C]CH3I). Total activity obtained was 5·6–7·4 GBq. The preparations have been demonstrated to be chemically and radiochemically pure by HPLC. Copyright © 2000 John Wiley & Sons, Ltd.

Donepezil (1-benzyl-4-[(5,6-dimethoxy-1-oxoindan-2-yl)methyl-]piperidine), a potent acetylcholine esterase inhibitor, was labelled with [¹¹C]iodomethane by O-methylation of the O-6'-desmethyl precursor. Synthesis, purification and formulation were performed in approximately 30 min with an average specific activity of 39.5 GBq/μmol at EOS. The total activity available for applications was 7.5–11.1 GBq. Copyright © 2000 John Wiley & Sons, Ltd.