- In vitro drug metabolism by human carboxylesterase 1: Focus on angiotensin-converting enzyme inhibitors
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Carboxylesterase 1 (CES1) is the major hydrolase in human liver. The enzyme is involved in the metabolism of several important therapeutic agents, drugs of abuse, and endogenous compounds. However, no studies have described the role of human CES1 in the activation of two commonly prescribed angiotensinconverting enzyme inhibitors: enalapril and ramipril. Here, we studied recombinant human CES1-and CES2-mediated hydrolytic activation of the prodrug esters enalapril and ramipril, compared with the activation of the known substrate trandolapril. Enalapril, ramipril, and trandolapril were readily hydrolyzed by CES1, but not by CES2. Ramipril and trandolapril exhibited Michaelis-Menten kinetics, while enalapril demonstrated substrate inhibition kinetics. Intrinsic clearances were 1.061, 0.360, and 0.02 ml/min/mg protein for ramipril, trandolapril, and enalapril, respectively. Additionally, we screened a panel of therapeutic drugs and drugs of abuse to assess their inhibition of the hydrolysis of p-nitrophenyl acetate by recombinant CES1 and human liver microsomes. The screening assay confirmed several known inhibitors of CES1 and identified two previously unreported inhibitors: the dihydropyridine calcium antagonist, isradipine, and the immunosuppressive agent, tacrolimus. CES1 plays a role in the metabolism of several drugs used in the treatment of common conditions, including hypertension, congestive heart failure, and diabetes mellitus; thus, there is a potential for clinically relevant drug-drug interactions. The findings in the present study may contribute to the prediction of such interactions in humans, thus opening up possibilities for safer drug treatments. Copyright
- Thomsen, Ragnar,Rasmussen, Henrik B.,Linnet, Kristian
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- Captopril inhibits the oxidative modification of apolipoprotein B-100 caused by myeloperoxydase in a comparative in vitro assay of angiotensin converting enzyme inhibitors
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The oxidative modification of low-density lipoproteins (LDL) is a key event in the formation of atheromatous lesions. Indeed, oxidized derivatives accumulate in the vascular wall and promote a local inflammatory process which triggers the progression of the atheromatous plaque. Myeloperoxidase (MPO) has been mentioned as a major contributor to this oxidative process. It takes part in the oxidation both of lipids by chlorination and peroxidation and of apolipoprotein B-100. Based on recent observations with several anti-inflammatory and thiol-containing drugs, the present study was designed to test the hypothesis that anti-hypertensive agents from the angiotensin converting enzyme (ACE) inhibitors group inhibit the oxidative modifications of Apo B-100 caused by MPO. Captopril, ramipril, enalapril, lisinopril and fosinopril were assessed by measuring: their inhibiting effect on the MPO / H2O2 / Cl- system, the accumulation of compound II, which reflects the inhibition of the synthesis of HOCl and the LDL oxidation by MPO in presence of several concentrations of ACE inhibitors. Only captopril, a thiol-containing ACE inhibitor, was able to significantly decrease the oxidative modification of LDL in a dose dependent manner and this by scavenging HOCl. This efficient anti-hypertensive drug therefore appears to also protect against the atherosclerotic process by this newly documented mechanism.
- Van Antwerpen, Pierre,Legssyer, Ilham,Zouaoui Boudjeltia, Karim,Babar, Sajida,Moreau, Patrick,Moguilevsky, Nicole,Vanhaeverbeek, Michel,Ducobu, Jean,Neve, Jean
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- Direct monitoring of drug degradation by easy ambient sonic-spray ionization mass spectrometry: The case of enalapril
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Using enalapril maleate as a test case, the ability of ambient mass spectrometry, namely, via easy ambient sonic-spray ionization mass spectrometry (EASI-MS), to perform direct monitoring of drug degradation has been tested. Two manufacturing processes were investigated (direct compression and wet granulation), and the formation of degradation products was measured via both EASI-MS and high-performance liquid chromatography with ultraviolet detection for a total period of 18 months. Both techniques provide comparable results, which indicate that direct analysis by ambient mass spectrometric techniques presents a viable alternative for drug degradation monitoring with superior simplicity, throughput, and reliability (no sample manipulation), and comparable quantitative results. In terms of qualitative monitoring, the full mass spectra with intact species provided by EASI-MS allow for comprehensive monitoring of known and unknown (or unexpected) degradation products. Copyright
- Amaral, Phellipe H.,Fernandes, Raquel,Eberlin, Marcos N.,Hoeehr, Nelci F.
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p. 1269 - 1273
(2012/04/10)
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- Process for preparing pharmacologically acceptable salt of N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanyl amino acids
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There is provided a process for preparing a pharmacologically acceptable salt of N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanyl-amino acid which comprises condensing an amino acid and N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanine.N-carboxyanhydride under basic condition, carrying out decarboxylation under between neutral and acidic condition to obtain N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanyl-amino acid, and forming a pharmacologically acceptable salt thereof, wherein the production of a by-product (3): is suppressed by carrying out in an aqueous liquid a series of operations till formation of the pharmacologically acceptable salt or till isolation of the pharmacologically acceptable salt. The present invention enables to prepare the pharmacologically acceptable salt of N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanyl-amino acid having high quality, in a commercial scale with high yield and economical efficiency.
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- Rapid conversion of the new angiotensin converting enzyme inhibitor ramipril to its active metabolite in rats
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The rate of conversion of ramipril (Hoe 498), a new angiotensin converting enzyme (ACE) inhibitor, to its active metabolite was compared with that of enalapril. After intravenous administration to rats, ramipril was very rapidly desterified to its active moiety, ramiprilat. The ratio of the active metabolite level to the prodrug level in plasma at 5 min after administration was 10.7 for ramipril, which was about 5 times the ratio for enalapril. The in vitro conversion rates of ramipril were higher than those of enalapril in all rat tissue homogenates examined, including the liver, a main site of metabolism. The apparent Km values of ramipril and enalapril in the liver were 190 and 710 μmol/l, respectively, suggesting that ramipril has a higher affinity for esterase than enalapril. In conclusion, ramipril was superior to enalapril in efficiency of conversion to the active metabolite.
- Tabata,Yamazaki,Ohtake,Hayashi
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p. 865 - 867
(2007/10/02)
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- A Stereoselective Synthesis of N--L-alanine Derivatives by Means of Reductive Amination
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A stereoselective synthesis of N--L-alanine, a portion of the molecule of angiotensin converting-enzyme(ACE) inhibitors, by reductive amination utilizing catecholborane and further applications of the reaction to the synthesis of ACE inhibitors are described.
- Iwasaki, Genji,Kimura, Rieko,Numao, Naganori,Kondo, Kiyoshi
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p. 1691 - 1694
(2007/10/02)
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