SPE for Endo- and Exo-Iohexol Analysis with HPLC in Canine Serum and Rat Urine

Klenner, Stefanie; Bergmann, Carl; Strube, Katrin; Ternes, Waldemar; Spillmann, Thomas

doi:10.1365/s10337-007-0202-1

Cited by 13 publications

(19 citation statements)

References 15 publications

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“…Generally, the nanoporous materials of the NN series are prepared by introducing many methylene (-CH 2 -) links between pairs of phenyl rings in styrene-divinylbenzene copolymer beads taken in a strongly swollen state [4,5]. The thus prepared hypercrosslinked polystyrenes already found wide application as highly efficient adsorbing materials [6][7][8][9], in particular, for SPE of organic pollutants [10][11][12][13]. The polymers possess a rigid open network structure with a highly developed system of small pores.…”

Section: Introductionmentioning

confidence: 99%

Self‐concentration effects in preparative SEC of mineral electrolytes using nanoporous neutral polymeric sorbents

Davankov

Tsyurupa

Blinnikova

et al. 2008

J of Separation Science

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Separation of mineral electrolytes according to size exclusion mechanism using neutral nanoporous polystyrene sorbents and carbonaceous materials has been examined in detail on hand of HCl and CaCl2 solutions, taken separately and in the mixture. Phase distribution coefficients of the above electrolytes have been measured under static conditions at different concentrations. The k-values and their dependence on the concentration were correlated with the elution curves of the components from a chromatographic column. Both the static and dynamic data suggest a strong dependence of the hydration number and effective size of ions on the concentration. Self-concentration of HCl in small pores and that of CaCl2 outside of small pores exhibits itself in both static and chromatographic experiments and results from the relocation of the components largely within the volume of the initial mixture. Additional apparent "retention" of HCl in the porous volume of the sorbent in concentrated electrolyte mixtures was shown to be caused by the competition between all ions of the system for hydration water. Increased separation selectivity and enhanced self-concentration effects for more concentrated mixtures point to preparative and industrial perspectives of size exclusion chromatography (SEC) of complex electrolyte mixtures on nanoporous neutral sorbents.

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Section: Introductionmentioning

confidence: 99%

Self‐concentration effects in preparative SEC of mineral electrolytes using nanoporous neutral polymeric sorbents

Davankov

Tsyurupa

Blinnikova

et al. 2008

J of Separation Science

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“…As this method requires an acid precipitation of the proteins extraction steps, we used PAH as an internal standard. Although Cavalier et al did not use any internal standard in their method , Klenner et al chose the sodium diatrizoate dehydrate. We suggest that it is important to correct for a possible loss of analyte during sample preparation or sample inlet.…”

Section: Discussionmentioning

confidence: 99%

Routine Determination of GFR in Renal Transplant Recipients by HPLC Quantification of Plasma Iohexol Concentrations and Comparison With Estimated GFR

Castagnet¹,

Blasco

Vourc’h

et al. 2012

Clinical Laboratory Analysis

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Estimated glomerular filtration rate (eGFR) methods are not sufficiently reliable in renal transplant recipients (RTR) and should be replaced by iohexol plasma clearance measurement. However, this method has poor availability in health centers. The aim of our study was to develop a high-performance liquid chromatography (HPLC) method for plasma iohexol measurement in routine practice and to evaluate its plasma clearance as a reference of GFR. We developed an HPLC method using UV detection. We evaluated sample storage conditions to provide recommendations for routine practice. Then, we compared GFRbased on plasma iohexol clearance (GFR-iohexol) to eGFR using modification of diet in renal disease, Cockcroft and Gault, and CDK-EPIequations in 40 RTR. The method was validated over a concentration range of 15-300 μg/l. Excellent linearity (r > 0.998), inter- and intraday precision (CV < 3.3%), and accuracy (>96.8%) were complied with ICH guidelines. We also demonstrated excellent samples stability (9 days). Although eGFR methods are not references in RTR, we found a correct concordance between eGFR and GFR-iohexol in our population. To conclude, our method is simple, rapid, accurate, and reliable for routine clinical and research use especially in RTR.

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“…Grade 3 ascites was evident in only those patients classified Child-Pugh B (4) or C. 10 The remaining patients had either no or grade 1 ascites. Median MELD score was 18 (12)(13)(14)(15)(16)(17)(18)(19)(20)(21) Cr-EDTA: chromium-51 labelled ethylenediamine tetraacetic acid; GFR: glomerular filtration rate; SD: standard deviation; IQR, inter-quartile range (25-75%).…”

Section: Patients and Study Designmentioning

confidence: 99%

Application of an isocratic methanol-based HPLC method for the determination of iohexol concentrations and glomerular filtration rate in patients with cirrhosis

et al. 2013

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Background: Glomerular filtration rate (GFR) and mortality is more accurately determined by gold standard measures than serum creatinine-based estimates in cirrhosis. No formal validation of any gold standard method has been reported. Methods: An isocratic methanol-based method incorporating the reference standard iohexol-related compound C was developed and validated in 12 patients with cirrhosis by simultaneously determining GFR using iohexol and chromium-51 labelled ethylenediamine tetraacetic acid ( 51 Cr-EDTA) clearance. Iohexol pharmacokinetics was also studied with the collection of blood and ascitic fluid at intervals following an iohexol bolus. Results: Triplicate assays produced a linear calibration curve (R 2 ¼ 0.99, N ¼ 5) over an iohexol concentration range of 23.6-755 mg/L. Mean (range) extraction recovery of iohexol from serum was greater than 95% (94-97%), with an intraday coefficient of variation less than 3%. Twelve patients with cirrhosis with mean Child-Pugh score of 9 displayed a mean difference (bias) À1.3 mL/min/1.73 m 2 (À18 to þ 16) comparing iohexol with 51 Cr-EDTA. Iohexol equilibrated between blood and ascitic compartments after 4 h. Conclusion: A simple, cheap, and accurate isocratic, methanol-based method for the determination of iohexol concentrations is described, validated according to Food and Drug Administration guidance. Iohexol demonstrated comparable performance with 51 Cr-EDTA in determining GFR. Delayed equilibrium of iohexol between blood and ascitic compartments suggests sampling beyond 4 h would improve accuracy of GFR determinations in patients with cirrhosis.

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SPE for Endo- and Exo-Iohexol Analysis with HPLC in Canine Serum and Rat Urine

Cited by 13 publications

References 15 publications

Self‐concentration effects in preparative SEC of mineral electrolytes using nanoporous neutral polymeric sorbents

Self‐concentration effects in preparative SEC of mineral electrolytes using nanoporous neutral polymeric sorbents

Routine Determination of GFR in Renal Transplant Recipients by HPLC Quantification of Plasma Iohexol Concentrations and Comparison With Estimated GFR

Application of an isocratic methanol-based HPLC method for the determination of iohexol concentrations and glomerular filtration rate in patients with cirrhosis

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