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GC-NICI-MS analysis of acetazolamide and other sulfonamide (R-SO2-NH2)drugs as pentafluorobenzyl derivatives [R-SO2-N(PFB)2] and quantification of pharmacological acetazolamide in human urine

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Journal of Pharmaceutical Analysis 2020年第1期10卷 49-59页

作者： Olga Begou Kathrin Drabert Georgios Theodoridis dimitrios tsikas Institute of Toxicology Core Unit ProteomicsHannover Medical SchoolCarl-Neuberg-Strasse 1D-30625HannoverGermany Department of Chemistry Aristotle University of Thessaloniki54124ThessalonikiGreece BIOMIC_AUTh Center for Interdisciplinary Research and Innovation(CIRI-AUTH)Balkan Center10th Km Thessaloniki-Thermi RdP.O.Box 8318GR 57001ThessalonikiGreece

Acetazolamide(molecular mass(MM),222)belongs to the class of sulfonamides(R-SO2-NH2)and is one of the strongest pharmacological inhibitors of carbonic anhydrase *** is excreted unchanged in the ***,we report on the development,validation and biomedical application of a stable-isotope dilution GC-MS method for the reliable quantitative determination of acetazolamide in human *** method is based on evaporation to dryness of 50 mL urine aliquots,base-catalyzed derivatization of acetazolamide(d0-AZM)and its internal standard[acetylo-2H3]acetazolamide(d3-AZM)in 30 vol%pentafluorobenzyl(PFB)bromide in acetonitrile(60 min,30C),reconstitution in toluene(200 mL)and injection of 1-mL *** negative-ion chemical ionization(NICI)mass spectra(methane)of the PFB derivatives contained several intense ions including[M]‒at m/z 581 for d0-AZM and m/z 584 for d3-AZM,suggesting derivatization of their sulfonamide groups to form N,N-dipentafluorobenzyl derivatives(R-SO2-N(PFB)2),i.e.,d0-AZM-(PFB)2 and d3-AZM-(PFB)2,*** was performed by selected-ion monitoring of m/z 581 and 83 for d0-AZM-(PFB)2 and m/z 584 and 86 for d3-AZM-(PFB)*** limits of detection and quantitation of the method were determined to be 300 fmol(67 pg)and 1 mM of acetazolamide,***-and inter-assay precision and accuracy for acetazolamide in human urine samples in pharmacologically relevant concentration ranges were determined to be 0.3%e4.2%and 95.3%e109%,*** method was applied to measure urinary acetazolamide excretion after ingestion of a 250 mg acetazolamide-containing tablet(Acemit®)by a healthy *** other tested sulfonamide drugs,methazolamide(MM,236)was also found to form a N,N-dipentafluorobenzyl derivative,whereas dorzolamide(MM,324)was hardly *** GC-MS peaks were obtained from the PFB bromide derivatization of hydrochlorothiazide(MM,298),xipamide(MM,355),indapamide and metholazone(MM,366 each)or br

关键词： Acetazolamide Derivatization Quantification Sulfonamides Validation

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S-Adenosyl-L-methionine towards hepatitis C virus expression: Need to consider S-Adenosyl-L-methionine's chemistry, physiology and pharmacokinetics

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World Journal of Gastroenterology 2017年第40期23卷 7343-7346页

作者： dimitrios tsikas Erik Hanff Alexander Bollenbach Core Unit Proteomics Hannover Medical School

S-Adenosyl-L-methionine(SAM) is a cofactor serving as a methyl donor in numerous enzymatic reactions. It has been reported that SAM has the potential to modify antioxidant-enzymes, glutathione-biosynthesis and methionine adenosyltransferases-1/2 in hepatitis C virus-expressing cells at millimolar concentrations. The efficacy of SAM at micromolar concentrations and the underlying mechanisms remain to be demonstrated.

关键词： S-Adenosyl-L-methionine Bioavailability Concentration Liver

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S-Nitroso-N-acetyl-L-cysteine ethyl ester(SNACET) and N-acetyl-L-cysteine ethyl ester(NACET)–Cysteine-based drug candidates with unique pharmacological profiles for oral use as NO, H_2S and GSH suppliers and as antioxidants: Results and overview

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Journal of Pharmaceutical Analysis 2018年第1期8卷 1-9页

作者： dimitrios tsikas Kathrin S.Schwedhelm Andrzej Surdacki Daniela Giustarini Ranieri Rossi Lea Kukoc-Modun George Kedia Stefan ückert Institute of Toxicology Core Unit Proteomics Hannover Medical School Second Department of Cardiology Jagiellonian University Medical College Department of Medicine Surgery and Neuroscience University of Siena Department of Life Sciences Laboratory of Pharmacology and Toxicology University of Siena Department of Analytical Chemistry Faculty of Chemistry and Technology University of Split Department of Urology and Urological Oncology Hannover Medical School

S-Nitrosothiols or thionitrites with the general formula RSNO are formally composed of the nitrosyl cation(NOt) and a thiolate(RSà), the base of the corresponding acids RSH. The smallest S-nitrosothiol is HSNO and derives from hydrogen sulfide(HSH, H_2S). The most common physiological S-nitrosothiols are derived from the amino acid L-cysteine(Cys SH). Thus, the simplest S-nitrosothiol is S-nitroso-L-cysteine(Cys SNO). Cys SNO is a spontaneous potent donor of nitric oxide(NO) which activates soluble guanylyl cyclase to form cyclic guanosine monophosphate(c GMP). This activation is associated with multiple biological actions that include relaxation of smooth muscle cells and inhibition of platelet *** NO, Cys SNO is a short-lived species and occurs physiologically at concentrations around 1 n M in human blood. Cys SNO can be formed from Cys SH and higher oxides of NO including nitrous acid(HONO)and its anhydride(N_2O_3). The most characteristic feature of RSNO is the S-transnitrosation reaction by which the NOtgroup is reversibly transferred to another thiolate. By this way numerous RSNO can be formed such as the low-molecular-mass S-nitroso-N-acetyl-L-cysteine(SNAC) and S-nitroso-glutathione(GSNO), and the high-molecular-mass S-nitrosol-L-cysteine hemoglobin(Hb Cys SNO) present in erythrocytes and S-nitrosol-L-cysteine albumin(Alb Cys SNO) present in plasma at concentrations of the order of 200 n M. All above mentioned RSNO exert NO-related biological activity, but they must be administered intravenously. This important drawback can be overcome by lipophilic charge-free ***, we prepared the ethyl ester of SNAC, the S-nitroso-N-acetyl-L-cysteine ethyl ester(SNACET), from synthetic N-acetyl-L-cysteine ethyl ester(NACET). Both NACET and SNACET have improved pharmacological features over N-acetyl-L-cysteine(NAC) and S-nitroso-N-acetyl-L-cysteine(SNAC), respectively,including higher oral bioavailability. SNACET exerts NO-related activities which can be

关键词： CGMP Nitric oxide S-Nitrosothiols Oxidative stress Pharmaceuticals

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