- 11C-Radiosynthesis and preliminary human evaluation of the disposition of the ACE inhibitor [11C]zofenoprilat
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(4S)-1-[(S)-3-Mercapto-2-methylpropanoyl]-4-phenylthio-L-proline (Zofenoprilat, 2), the active metabolite of the potent ACE inhibitor Zofenopril Calcium (1), was labelled with carbon-11 (t1/2=20.4 min) to evaluate its pharmacokinetics behaviour in human body using Positron Emission Tomography (PET). [11C]2 labelling procedures were based on the use of immobilized Grignard reagent and the acylation of (S)-4-phenylthio-L-proline methyl ester (5) with 11C-labelled methacryloyl chloride, followed by a Michael addition with thiobenzoic acid. The radiochemical yield was 5-10% (EOB, decay corrected) and specific radioactivity ranged from 0.5 to 1.5 Ci/μmol (18.5-55.5 GBq/μmol). Preliminary in vivo human evaluation of [11C]2 showed that the drug accumulates in organs which express high levels of ACE, like lungs and kidneys, and in organs involved in drug metabolism such as the liver and gall bladder. Results of the distribution of [11C]2 showed a measurable concentration of the drug in the target tissues such as the kidney and to a minor extent, the heart, where it can afford organ protection.
- Matarrese, Mario,Salimbeni, Aldo,Turolla, Elia Anna,Turozzi, Damiano,Moresco, Rosa Maria,Poma, Davide,Magni, Fulvio,Todde, Sergio,Rossetti, Claudio,Sciarrone, Maria Teresa,Bianchi, Giuseppe,Kienle, Marzia Galli,Fazio, Ferruccio
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p. 603 - 611
(2007/10/03)
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- Angiotensin-converting enzyme inhibitors. Mercaptan, carboxyalkyl dipeptide, and phosphinic acid inhibitors incorporating 4-substituted prolines
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Analogues of captopril, enalaprilat, and the phosphinic acid [[hydroxy(4-phenylbutyl)phosphinyl]acetyl)-L-proline incorporating 4-substituted proline derivatives have been synthesized and evaluated as inhibitors of angiotensin-converting enzyme (ACE) in vitro and in vivo. The 4-substituted prolines, incorporating alkyl, aryl, alkoxy, aryloxy, alkylthio, and arylthio substituents were prepared from derivatives of 4-hydroxy- and 4-ketoproline. In general, analogues of all three classes of inhibitors with hydrophobic substituents on proline were more potent in vitro than the corresponding unsubstituted proline compounds. 4-Substituted analogues of captopril showed greater potency and duration of action than the parent compound as inhibitors of the angiotensin I induced pressor response in normotensive rats. The S-benzoyl derivative of cis-4-(phenylthio)captopril, zofenopril, was found to be one of the most potent compounds of this class and is now being evaluated clinically as an antihypertensive agent. In the phosphinic acid series, the 4-ethylenethioketal and trans-4-cyclohexyl derivatives were found to be the most potent compounds in vitro and in vivo. A prodrug of the latter compound, fosinopril, is also being evaluated in clinical trials.
- Krapcho,Turk,Cushman,Powell,DeForrest,Spitzmiller,Karanewsky,Duggan,Rovnvak,Schwartz,Natarajan,Godfrey,Ryono,Neubeck,Atwa,Petrillo Jr.
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p. 1148 - 1160
(2007/10/02)
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