Analysis of Urinary Pseudouridine by Micellar Electrokinetic Capillary Chromatography

1997 ◽  
Vol 34 (5) ◽  
pp. 527-533 ◽  
Author(s):  
M D Evans ◽  
D Perrett ◽  
J Lunec ◽  
K E Herbert
Keyword(s):  
Chromatographic Analysis ◽  
Healthy Subjects ◽  
Solid Phase ◽  
Internal Standard ◽  
Resolving Power ◽  
Capillary Chromatography ◽  
Chromatographic Techniques ◽  
Coefficients Of Variation ◽  
The Mean ◽  
Electrokinetic Capillary Chromatography

We describe a capillary electrophoresis procedure, using uridine as an internal standard, for the analysis of urinary pseudouridine following solid-phase extraction. This method retains the advantages of existing chromatographic techniques but has superior resolving power and is technically less demanding. The standard curves were linear and reproducible with a detection limit of 60 fmol; chromatographic analysis was complete in under 10min. Injection variability was <5% and multiple independent analyses of the same urine sample for pseudouridine concentration gave coefficients of variation of < 10%. The mean (SD) urinary pseudouridine level in 18 healthy subjects was 16·1 (2·l)nmol/μmol creatinine. For a limited group of subjects where samples were taken more frequently, intra-individual variation averaged 27.5% reflecting variable excretion.

Determination of plasma procainamide and N-acetylprocainamide concentration by high-pressure liquid chromatography.

1977 ◽  
Vol 23 (7) ◽  
pp. 1318-1320 ◽  
Author(s):  
J S Dutcher ◽  
J M Strong
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Antiarrhythmic Drug ◽  
Chromatographic Analysis ◽  
Active Metabolite ◽  
Internal Standard ◽  
Routine Method ◽  
Simple Extraction ◽  
The Mean

Abstract We describe a routine method for determining concentrations of the antiarrhythmic drug procainamide and its active metabolite, N-acetylprocainamide, in plasma. A simple extraction of 1.0 ml of plasma is followed by separation and chromatographic analysis by use of a column containing microparticulate silica. p-nitro-N-(2-diethylaminoethyl)benzamide hydrochloride was synthesized and used as the internal standard. Total chromatographic time is only 7 min. The day-to-day CV during three months of daily use was less than 4% of the mean for each compound, and we saw no deterioration in column performance during this time. Phenobarbital, phenytoin, lidocaine, primidone, methsuximide, quinidine, and their metabolites do not interfere.

Liquid chromatographic analysis of disopyramide and its mono-N-dealkylated metabolite.

1979 ◽  
Vol 25 (3) ◽  
pp. 405-408 ◽  
Author(s):  
J J Lima
Keyword(s):  
Chromatographic Analysis ◽  
Mobile Phase ◽  
High Performance ◽  
Antiarrhythmic Drugs ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic ◽  
Lower Limits

Abstract We describe a rapid, sensitive, and specific "high performance" liquid chromatographic analysis for disopyramide and its mono-N-dealkylated metabolite in serum, urine, and saliva. We used a mu-Bondapak CN column and an acetate buffer mobile phase containing methanol. Retention times for the two compounds and the internal standard, p-chlorodisopyramide, were 3.4, 4.1, and 6.3 min, respectively. The lower limits of sensitivity for drug and metabolite were 50 and 80 micrograms/L, respectively, with maximum coefficients of variation of 4.6 and 12%, respectively. Currently used antiarrhythmic drugs did not interfere with the analysis of disopyramide, and the pharmacokinetics of the drug, obtained from studies of one subject, agree well with reported values.

High Plasma Levels of Human Chromogranin a and Adrenomedullin in Patients with Pheochromocytoma

2005 ◽  
Vol 91 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Dario Cotesta ◽  
Chiara Caliumi ◽  
Piero Alò ◽  
Luigi Petramala ◽  
Maria Gabriella Reale ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Biochemical Parameters ◽  
Chromogranin A ◽  
Solid Phase ◽  
High Plasma ◽  
Tumor Removal ◽  
Blood Samples ◽  
Adrenocortical Adenomas ◽  
Specific Radioimmunoassay ◽  
The Mean

Aims and background The aim of our study was to investigate the plasma chromogranin A (CgA) and adrenomedullin (AM) levels in patients with pheochromocytomas. Methods and study design We collected blood samples for measurement of plasma CgA and AM in 21 patients with pheochromocytomas, 43 healthy subjects and 26 patients with solid non-functioning adrenocortical adenomas. In 11 patients with pheochromocytomas plasma CgA and AM were measured again four weeks after tumor removal. CgA and AM were measured by means of a novel solid-phase two-site immunoradiometric assay based on monoclonal antibodies (CgA-RIA CT, CIS bio international) and by a specific radioimmunoassay (RIA, Phoenix Pharm. Inc.), respectively. Results The mean plasma CgA level (±SD) in patients with pheochromocytomas (204 ± 147.9 ng/mL) was significantly higher (P <0.001) than that in healthy subjects (41.6 ± 10.7 ng/mL) and in patients with non-functioning adrenocortical adenomas (47.3 ± 17.6 ng/mL). The mean plasma AM concentration (±SD) in patients with pheochromocytomas (27.5 ± 10.4 pg/mL) was significantly higher (P <0.001) than that in HS (13.8 ± 4.5 pg/mL) and in patients with non-functioning adrenocortical adenomas (16.6 ± 7.3 pg/mL). Plasma CgA levels correlated with plasma AM levels (r = 0.501; P <0.02) and with plasma metanephrine levels (r = 0.738; P <0.0001) in patients with pheochromocytomas. In 11 patients with pheochromocytomas plasma CgA and AM concentrations significantly decreased after tumor removal (P <0.001 for both). Circulating CgA and AM had a sensitivity of 76.2% and 81%, a specificity of 97.7% and 90.7%, and an accuracy of 91% and 88%, respectively. Conclusion This study demonstrates that circulating CgA and AM levels are increased in pheochromocytoma patients compared with healthy subjects and patients with non-functioning adrenocortical adenomas. Moreover, at the time of diagnosis plasma CgA levels correlated with plasma AM levels and with plasma metanephrine levels in all patients with pheochromocytomas. In conclusion, plasma CgA and AM concentrations may represent additional biochemical parameters for clinical monitoring of patients with pheochromocytomas.

scholarly journals Differentiation between naproxen, naproxen–protein conjugates, and naproxen–lysine in plasma via micellar electrokinetic capillary chromatography—a new approach in the bioanalysis of drug targeting preparations

1997 ◽  
Vol 43 (11) ◽  
pp. 2083-2090 ◽  
Author(s):  
Christiane Albrecht ◽  
Jürg Reichen ◽  
Jan Visser ◽  
Dirk K F Meijer ◽  
Wolfgang Thormann
Keyword(s):  
Serum Albumin ◽  
Drug Carrier ◽  
Internal Standard ◽  
Micellar Electrokinetic Capillary Chromatography ◽  
Capillary Chromatography ◽  
Total Plasma ◽  
New Approach ◽  
Protein Conjugates ◽  
Plasma Injection ◽  
Electrokinetic Capillary Chromatography

Abstract Pharmacotherapy through the targeting of drugs is a promising new approach that requires adequate analytical methods capable of differentiating between the free drug, the drug carrier, and metabolites. Using micellar electrokinetic capillary chromatography (MECC), we report the separation of naproxen (NAP) from NAP covalently coupled to human serum albumin or to mannosylated serum albumin and the metabolite naproxen–lysine. An assay for selective analysis of the different forms of NAP by direct plasma injection was developed with salicylate as internal standard and solute detection by laser-induced fluorescence. Compared with previously applied techniques, including HPLC and total plasma fluorescence, MECC offers the advantage that free and covalently bound NAP can be differentiated in one run and can be accurately monitored in microliter quantities of plasma. Summation of all NAP equivalents determined by MECC revealed data that compare well with those produced by total plasma fluorescence and HPLC.

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