High-Performance Liquid-Chromatographic Measurement of Plasma Creatinine in Newborns

1992 ◽  
Vol 38 (1) ◽  
pp. 101-103 ◽  
Author(s):  
Paul H Scott

Abstract This HPLC method for measuring plasma creatinine is based on cation-exchange chromatography and is particularly suitable for use with specimens from babies. A short chromatographic run is performed after simple protein precipitation with zinc sulfate and addition of an internal standard, N-methylnicotinamide. The standard curve for the method is linear up to 200 mumol/L, and analytical recovery of added creatinine is between 101% and 103%. Between-batch precision (CV) is less than 3% for mean creatinine values of 103 and 164 mumol/L. The method is free of interference from other metabolic components and drugs commonly used in neonates in routine clinical practice. Using specimens from neonates, I compared this method with a routinely used automated alkaline picrate method (from Randox Labs., performed on a Cobas MIRA analyzer). Linear-regression analysis yielded a correlation coefficient of 0.90, a slope of 1.00, and an intercept of +0.8 mumol/L. This HPLC method for creatinine should be of use in those circumstances where the alkaline picrate method is known to produce dubious results; however, the latter method is probably more suitable for routine use.

2011 ◽  
Vol 8 (s1) ◽  
pp. S41-S46
Author(s):  
Prafulla Kumar Sahu ◽  
M. Mathrusri Annapurna ◽  
Dillipkumar Sahoo

This paper describes a high-performance liquid chromatographic method for simultaneous estimation of nabumetone and paracetamol in binary mixture. The method was based on RP-HPLC separation and quantitation of the two drugs on hypersil C-18 column (250 mm × 4.6 mm) using a mobile phase consisting of acetonitrile and 0.05% aqueous acetic acid (70:30v/v) at flow rate of 1 mL min-1. Quantitation was achieved with PDA detector at 238 nm based on peak area with linear calibration curves at concentration ranges 5-25 µg mL-1for both the drugs. Naproxen sodium was used as internal standard. The method has been successively applied to pharmaceutical formulation. No chromatographic interference from the tablet excipients was found. The method was validated in terms of precision, robustness, recovery and limits of detection and quantitation. The intra and inter-day precision and accuracy values were in the acceptance range as per ICH guidelines.


2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Hong Yan ◽  
Pei Xu ◽  
Hai Huang ◽  
Juan Qiu

AbstractA pre-column derivatized high-performance liquid chromatographic (HPLC) method with ultraviolet-visible detection was developed to measure the concentrations of spectinomycin in fermentation broth. Derivatization reagents, 2,4-dinitrophenylhydrazine in acetonitrile (5 mg mL−1) and trifluoroacetic acid in acetonitrile (0.8 mol L−1), were added to an aliquot of the fermentation broth, and the mixture was incubated for 60 min at 70°C. The resulting derivative was separated from other compounds by isocratic elution in a reversed-phase column Zorbax SB-C18 (250 mm × 4.6 mm, 5 µm). Mobile phase consisted of acetonitrile, tetrahydrofuran, and water (φ r = 40: 35: 25) and the flow rate was 1.0 mL min−1. The detection wavelength was 415 nm. The standard curve for spectinomycin sulfate was linear with correlation coefficients of 0.9997 in the range of 25 µg mL−1 to 600 µg mL−1. The relative standard deviation values ranged from 0.43 % to 2.18 % depending on the concentration of samples. The average recovery was 101.5 %. The limit of detection was 50 ng mL−1.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Nitin Dubey ◽  
Nidhi Dubey ◽  
Rajendra Mehta

A simple, sensitive, and selective high-performance liquid chromatographic (HPLC) method has been developed and validated for the analysis of aconitine in marketed ayurvedic taila (oil) formulations containing roots of Aconitum chasmanthum. Chromatography of methanolic extracts of these formulations was performed on C18 (5 μm × 25 cm × 4.6 mm i.d.) column using isocratic mobile phase consisting of (65 : 35% v/v) acetonitrile and buffer solution (aqueous 0.01 M ammonium bicarbonate buffer, adjusted to pH 9.6 using 30% ammonia solution) at a flow rate of 1 mL/min and SPD-10 AVP photodiode array (PDA) UV-Visible detector. The analytical reference, aconitine, was quantified at 238 nm. The retention time of aconitine was about 42.54 min. The linear regression analysis data for the calibration plot showed a good linear relationship with correlation coefficient of 0.9989 in the concentration range of 15 to 90 μg/mL for aconitine with respect to peak area. The limit of detection and limit of quantitation values were found to be 0.03 μg/mL and 0.1 μg/mL respectively. Repeatability of the method was found to be 0.551–1.689 RSD. Recovery values from 97.75 to 99.91% indicate excellent accuracy of the method. The developed HPLC method is accurate and precise and it can be successfully applied for the determination of aconitine in marketed ayurvedic oil formulations containing Aconitum chasmanthum.


Author(s):  
Biljana Gjorgjeska

Ketoconazole has been widely used as an antifungal drug  that is formulated as tablets, cream and over­the­counter ketoconazole shampoo. The aim of this research was to study and to standardize an ultraviolet spectrophotometric (UVS) method, potentiometric  and a high  performance  liquid  chromatographic  (HPLC) method  for  the determination  of ketoconazole in commercially available Oromycosal® tablets. These three methods were compared and discussed with respect to  their  sensitivity,  selectivity  and ready­applicability  in  routine  analytical  work.   Absorption  spectra and spectrophotometric determinations were carried out on the UVS spectrophotometer. Investigated concentrations were in range from  0.003 to  0.02mg?dm­3. The absorbance was measured at 224  nm.  In potentiometric  titrations  glass  and saturated (KCl) calomel electrode were used. HPLC analyses of ketoconazole were carried in the presence of econazole as internal standard. It can be concluded that the described methods are simple, fast and reliable for determination of ketoconazole in pharmaceutical preparations. The preparation of the samples is easy, the excipients do not  interfere in the methods, so they can be used in routine quality control analysis.


1988 ◽  
Vol 34 (4) ◽  
pp. 724-729 ◽  
Author(s):  
M Hariharan ◽  
T VanNoord ◽  
J F Greden

Abstract We describe a rapid, sensitive method for the routine simultaneous determination of nicotine and cotinine in 1 mL of plasma. Extraction in 10-mL screw-capped Teflon tubes with methylene chloride after deproteinization with trichloroacetic acid eliminated emulsion formation. The extract, after evaporation and reconstitution in 30 microL of mobile phase, is injected into a reversed-phase C-18 ion-pair column of an isocratic high-performance liquid-chromatographic unit. Absorbance is monitored at 256 nm. The mobile phase is a citrate-phosphate (30 mmol each per liter) buffer mixture containing 50 mL of acetonitrile and 1 mmol of sodium heptanesulfonate per liter. 2-Phenylimidazole is the internal standard. The detection limit is 1 microgram/L for nicotine and 3 micrograms/L for cotinine. The standard curve is linear from 0 to 700 micrograms/L for both compounds. The average CV for nicotine in the concentration range 0-100 micrograms/L is 6.5%, and that for cotinine in the concentration range 50-700 micrograms/L is 4%.


1988 ◽  
Vol 34 (12) ◽  
pp. 2502-2503 ◽  
Author(s):  
P A Hynning ◽  
P Anderson ◽  
U Bondesson ◽  
L O Boréus

Abstract A high-performance liquid chromatographic (HPLC) method for determining verapamil and norverapamil in plasma is presented and compared with gas chromatography/mass spectrometry (GC-MS). The plasma samples were extracted at alkaline pH with hexane containing 2-butanol (20 mL/L) and then back-extracted into phosphate buffer (0.1 mol/L, pH 3.0). For chromatography we used a reversed-phase column (Supelcosil LC-18 DB) with a mobile phase of the phosphate buffer and acetonitrile (70/30 by vol). Fluorescence detection was used (excitation at 203 nm, emission at 320 nm). Overall analytical recovery was 85%. Standard curves were linear from 1 to 1000 micrograms/L. The detection limit was 1 microgram/L. The assays are accurate and precise. We found no interferences by those substances tested. Results by HPLC and GC-MS agreed well (r = 0.99) for both verapamil and norverapamil determinations.


1987 ◽  
Vol 33 (10) ◽  
pp. 1841-1850 ◽  
Author(s):  
G L Lensmeyer ◽  
D A Wiebe ◽  
I H Carlson

Abstract We describe an extraction and an isocratic "high-performance" liquid-chromatographic (HPLC) separation of cyclosporine (CsA) and nine metabolites (M1, M8, M17, M18, M21, M25, M26, M203-218, and MUNDF1) from whole blood. Metabolites (for standards) were purified from human bile with liquid-liquid and solid-phase extractions, chromatographed on a cyanopropyl (CN) semipreparative HPLC column, and further purified on octyl, CN, and silica columns. The identity of each metabolite was verified with authentic standards on three chemically different HPLC columns and on the basis of cross-reactivity data from radioimmunoassay. For the routine analytical method, 1 mL of whole blood is diluted, hemolyzed, and applied to a Bond Elut CN (500 mg) cartridge to extract CsA, metabolites, and cyclosporin C, the internal standard. Interferences are removed by using four wash solutions and an additional cartridge of octyldecyl sorbent introduced prior to elution. Analytes are separated on a Zorbax CN analytical column maintained at 58 degrees C, with detection at 214 nm. Analytical recovery, as tested with three lots of CN sorbent, ranged from 47% to 95% for the 10 cyclosporines. Between-run CVs are less than 10% at 200 micrograms/L (concentration of each compound) and the standard curves are linear to 1500 micrograms/L. We also report a study of the separation mechanisms.


1988 ◽  
Vol 34 (9) ◽  
pp. 1897-1899 ◽  
Author(s):  
M H Cheng ◽  
W Y Huang ◽  
A I Lipsey

Abstract This high-performance liquid-chromatographic (HPLC) method for simultaneous determination of prednisone and its metabolite, prednisolone, in plasma is a modification of the method of Frey et al. (Clin Chem 1979;25:1944-7). Heparinized plasma (1.0 mL) with 0.1 mL of internal standard solution (11-deoxy-17-hydroxycorticosterone, 2 mg/L) is extracted with 7.0 mL of dichloromethane, then washed sequentially with 0.1 mol/L HCl, 0.1 mol/L NaOH, and deionized water, 2.0 mL each. The extract is evaporated and the residue reconstituted with 75 microL of mobile phase, methanol/H2O (40/60 by vol). Thirty microliters of this is injected onto a reversed-phase C6 column, which is eluted at 1.4 mL/min. Analytical recoveries of prednisone and prednisolone were 94-98% and 102-106%, respectively. Day-to-day precision (CV) was 3.8% for prednisone, 6.1% for prednisolone. We encountered no interference from the 21 other steroids and 25 drugs tested. This method is simple, accurate, and precise.


1985 ◽  
Vol 31 (2) ◽  
pp. 196-201 ◽  
Author(s):  
G L Lensmeyer ◽  
B L Fields

Abstract This unique extraction and isocratic "high-performance" liquid chromatographic method for measuring cyclosporine (CsA) in blood involves a Zorbax cyanopropyl analytical column maintained at 58 degrees C, with detection at 214 nm, and recycling of the water:acetonitrile mobile phase for improved long-term column stability and efficiency. Routinely, 1.0 mL of serum, plasma, or whole blood is diluted with water:acetonitrile (70:30) and applied to a disposable solid-phase cyanopropyl column to rapidly extract the drug and the internal standard cyclosporin D (CsD). Analytical recovery for this step averages 90% with whole blood and 98% with serum and plasma. Between-run CVs were 6.5 and 2.6% for means of 104 and 1128 micrograms/L, respectively. The standard curve is linear up to 1600 micrograms/L. The minimum detection limit is 10 to 15 micrograms/L. No interferences from endogenous substances or other drugs were found. In addition, a compound cross reacting with the Sandoz radioimmunoassay antibody was isolated from patients' samples with the present procedure and was tentatively identified as a CsA metabolite(s). It appears to be highly partitioned on blood cells, very little being detected in the serum or plasma. In a comparison with RIA, correlation coefficients were 0.828 and 0.652 for serum and whole blood, respectively. Results from a 12-h pharmacokinetic study in which different sample types were analyzed by RIA and liquid chromatography further exemplified major discrepancies between types of CsA determinations.


1985 ◽  
Vol 31 (9) ◽  
pp. 1564-1565 ◽  
Author(s):  
P Boyne ◽  
B A Robinson ◽  
P Murphy ◽  
M McKay

Abstract We evaluated a simple, specific method for measuring plasma creatinine concentration, involving enzymatic degradation of creatinine before analysis by a kinetic Jaffé reaction. The enzymes--prepared in a dry, stable form--are convenient to use and eliminate the need to correct for sample dilution. As little as 50 microL of plasma is required, making the procedure ideal for use with samples from children. Between-day precision studies for determination of plasma creatinine at concentrations of 70 and 470 mumol/L yielded CVs of 7.8 and 4.3%, respectively. Analytical recovery of creatinine added to plasma samples ranged from 94 to 113%. Linear regression analysis demonstrated excellent agreement between results by this method and those by a "high performance" liquid-chromatographic technique.


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