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Semipreparative HPLC (semipreparative + hplc)
Selected AbstractsSynthesis and biological evaluation of [carboxyl - 11C]eprosartanJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 8 2009Ola Ĺberg Abstract Essential hypertension occurs in approximately 25% of the adult population and one cause of hypertension is primary aldosteronism. Targeting the angiotensin II AT1 receptor using PET and an appropriate tracer may offer a diagnostic method for adrenocortical tissue. This report describes the synthesis of the selective AT1 receptor antagonist [carboxyl - 11C]eprosartan 10, 4-[2-butyl-5-((E)-2-carboxy-3-thiophen-2-yl-propenyl)-imidazol-1-ylmethyl]-[carboxyl - 11C]benzoic acid, and its precursor (E)-3-[2-butyl-3-(4-iodo-benzyl)-3H -imidazol-4-yl]-2-thiophen-2-ylmethyl-acrylic acid 9. 11C-carboxylation of the iodobenzyl moiety was performed using a palladium-mediated reaction with [11C]carbon monoxide in the presence of tetra- n -butyl-ammonium hydroxide in a micro-autoclave using a temperature gradient from 25 to 140°C over 5,min. After purification by semipreparative HPLC, [carboxyl - 11C]eprosartan 10 was obtained in 37,54% decay-corrected radiochemical yield (from [11C]carbon monoxide) with a radiochemical purity >95% within 35,min of the end of bombardment (EOB). A 5-µAh bombardment gave 2.04,GBq of 10 (50% rcy from [11C]carbon monoxide) with a specific activity of 160,GBq,µmol,1 at 34,min after EOB. Frozen-section autoradiography shows specific binding in kidney, lung and adrenal cortex. In vivo experiments in rats demonstrate a high accumulation in kidney, liver and intestinal wall. Copyright © 2009 John Wiley & Sons, Ltd. [source] Sequence diversity of the peptaibol antibiotic suzukacillin-A from the mold Trichoderma virideJOURNAL OF PEPTIDE SCIENCE, Issue 5 2006Corina Krause Abstract From the culture broth of the mold Trichoderma viride, strain 63 C-I, the polypeptide antibiotic suzukacillin (SZ) was isolated. A peptide mixture named SZ-A was obtained by crystallization from crude SZ. Individual peptides from SZ-A were isolated by semipreparative HPLC and sequences were determined by HPLC-ESI-MS. The data confirm a general sequence of SZ-A published previously and in addition establish the individual sequences of 15 acetylated eicosa peptides with C -terminal alcohols. The major peptide SZ-A4 (21% of all peptides) shows the sequence: Ac-Aib-Ala-Aib-Ala-Aib-Ala6 -Gln-Aib-Lx9 -Aib-Gly-Aib12 -Aib-Pro-Vx15 -Aib-Vx17 -Gln-Gln-Fol. Amino acid exchanges of the peptaibol are located in position 6 (Ala/Aib), 9 (Vx/Lx), 12 (Aib/Lx), 17 (Aib/Vx) and possibly at position15 (Val/Iva) (uncommon abbreviations: Aib (,-aminoisobutyric acid); Iva (D -isovaline); Lx (L -leucine or L -isoleucine); Vx (L -valine or D -isovaline); Fol (L -phenylalaninol)). Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd. [source] Impurities in a morphine sulfate drug product identified as 5-(hydroxymethyl)-2-furfural, 10-hydroxymorphine and 10-oxomorphineJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2003Seán S. Kelly Abstract Stability testing of morphine sulfate formulated with nonpareil sugar seeds (consisting of sucrose and starch) and fumaric acid revealed the formation of the three impurities 5-(hydroxymethyl)-2-furfural, 10-hydroxymorphine and 10-oxomorphine. 5-(Hydroxymethyl)-2-furfural was isolated via semipreparative HPLC utilizing volatile mobile phase constituents and was identified by analysis of its HRMS and NMR spectra. 10-Hydroxymorphine and 10-oxomorphine were obtained via semipreparative HPLC and subsequent removal of ion-pair reagents using an anion exchange resin, or by solid phase extraction, and identified by spectroscopic analysis followed by comparison with authentic materials. 5-(Hydroxymethyl)-2-furfural is a degradation product of hexose sugars, and its formation in the presence of morphine sulfate formulated with fumaric acid suggests that caution should be exercised when including nonpareil seeds in formulations that contain acidic drug salts and/or acid excipients. The preliminary results of tests on the interaction of acidic salts of some other drugs with nonpareil seeds are presented. © 2003 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 92:485,493, 2003 [source] Chiral HPLC separation and CD spectra of the enantiomers of the alkaloid tacamonine and related compoundsCHIRALITY, Issue 10 2001Salvatore Caccamese Abstract The HPLC enantiomeric separation of racemic indole alkaloids tacamonine, 17,-hydroxytacamonine, deethyleburnamonine, and vindeburnol was accomplished using Chiralpak AD and Chiralcel OD as chiral stationary phases. Small structural differences affect the enantioselectivity ability of these phases. Single enantiomers of tacamonine and vindeburnol were isolated by semipreparative HPLC and their CD spectra and optical rotations were measured. Chirality 13:691,693, 2001. © 2001 Wiley-Liss, Inc. [source] | ||||||||||