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.

A Simple Procedure for the Determination of Carbamazepine in Plasma by High Pressure-Liquid Chromatography

1979 ◽  
Vol 16 (1-6) ◽  
pp. 213-216 ◽  
Author(s):  
C. K. Johnston ◽  
G. H. Lester
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
High Pressure Liquid Chromatography ◽  
Mobile Phase ◽  
Simple Procedure ◽  
Internal Standard ◽  
Reverse Phase ◽  
Coefficients Of Variation ◽  
Initial Results

We describe a simple, rapid procedure for the estimation of carbamazepine in plasma. Protein is precipitated, and extraction is achieved by the addition of acetonitrile containing the internal standard N-acetyltryptophan ethyl ester. Separation is by reverse-phase high-pressure liquid chromatography with an acetonitrile: water mobile phase, and detection is by UV absorption at 280 nm. Total retention time is less than 7 minutes. Initial results gave within-batch and between-batch coefficients of variation of less than 2 %, and mean recovery of 97 %. The method is free from interference by other common anticonvulsant drugs.

Determination of acetaminophen and phenacetin in plasma by high-pressure liquid chromatography.

1977 ◽  
Vol 23 (6) ◽  
pp. 957-959 ◽  
Author(s):  
G R Gotelli ◽  
P M Kabra ◽  
L J Marton
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Chromatographic Method ◽  
Plasma Sample ◽  
Internal Standard ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Method ◽  
Toxic Concentrations ◽  
Liquid Chromatographic

Abstract We describe a sensitive and precise high-pressure liquid chromatographic method in which acetoacetanilide is used as the internal standard to simultaneously determine acetaminophen and phenacetin in plasma. Therapeutic as well as toxic concentrations can be determined on as little as 0.1 ml of plasma. Sample preparation is rapid and chromatography is complete in 5 min. Quantitation is accurate at 0.5 mg/liter concentration for both drugs. Day-to-day precision within 5% is attainable. Of 36 other drugs tested, only theophylline interfered, with the determination of acetaminophen.

Determination of acetaminophen concentrations in serum by high-pressure liquid chromatography.

1977 ◽  
Vol 23 (9) ◽  
pp. 1596-1598 ◽  
Author(s):  
R A Horvitz ◽  
P I Jatlow
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Diethyl Ether ◽  
High Pressure Liquid Chromatography ◽  
Internal Standard ◽  
Reversed Phase ◽  
Single Extraction ◽  
Toxic Concentrations

Abstract We describe a method for determination of serum acetaminophen concentrations in serum by reversed phase high-pressure liquid chromatography. The homolog N-propionyl-p-aminophenol was used as an internal standard. The procedure, which requires only a single extraction with diethyl ether, can be optimized to be linear over the ranges of 10 to 100 or 1 to 20 mg/liter. Within-run CV was 1.2%; between-run CV was 4.4% and 4.9% at two different concentrations. Many commonly used drugs were tested and found not to interfere. The procedure is simple and rapid enough for use on an emergency basis in cases of overdosage, and can be optimized for measurement of either therapeutic or toxic concentrations.

Monitoring clorazepate dipotassium as desmethyldiazepam in plasma by electron-capture gas--liquid chromatography.

1980 ◽  
Vol 26 (1) ◽  
pp. 142-144
Author(s):  
D Haidukewych ◽  
E A Rodin ◽  
R Davenport
Keyword(s):  
Liquid Chromatography ◽  
Electron Capture ◽  
Active Metabolite ◽  
Internal Standard ◽  
Gas Liquid Chromatography ◽  
Sensitivity Limit ◽  
One Step ◽  
The Mean ◽  
Pharmacologically Active ◽  
State Concentration

Abstract We describe a procedure for determing clorazepate dipotassium as its decarboxylated, pharmacologically active metabolite, desmethyldiazepam, in 100 microL of plasma, with use of electron-capture gas--liquid chromatography and with methylnitrazepam as the internal standard. The procedure is a one-tube, one-step extraction without derivative formation and is accurate, reproducible, and rapid. The sensitivity limit is 20 micrograms/L. Within-run and between-run CV's (concentration, 3.5 mg/L) were 2.9 and 3.5%, respectively. Within-run CV's for 1.5 and 1.0 mg/L concentrations were 3.9 and 4.3%, respectively. For a 1.0 mg/kg per day dose of clorazepate dipotassium, the mean steady-state concentration of desmethyldiazepam in plasma was 1.037 mg/L.

Nonaqueous reversed-phase liquid chromatography and fluorimetry compared for determination of retinol in serum.

1983 ◽  
Vol 29 (7) ◽  
pp. 1431-1434 ◽  
Author(s):  
H J Nelis ◽  
J De Roose ◽  
H Vandenbavière ◽  
A P De Leenheer
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Internal Standard ◽  
Reference Method ◽  
Reversed Phase ◽  
Routine Method ◽  
Reversed Phase Liquid Chromatography ◽  
Standard Curve ◽  
Phase Liquid

Abstract A new assay for retinol in human serum, based on nonaqueous reversed-phase liquid chromatography, is presented. Sample preparation includes addition of the internal standard, retinyl propionate, deproteinization of 100 microL of serum with acetonitrile, and extraction with hexane. The standard curve is linear up to 2 mg/L. The assay is characterized by excellent sensitivity (detection limit, 15 micrograms/L) and good within-run and between-run precision (CVs of 2.6 and 2.7%, respectively), and results compare favorably with those by fluorimetry. We assayed 135 samples from hospitalized patients by both methods. Although the two sets of values correlated well (r = 0.955) the fluorimetric method occasionally suffers from interferences. In practice, fluorimetry proves valuable as a routine method, while liquid chromatography meets the criteria of a potential reference method.

Gas-chromatographic analysis for therapeutic concentrations of amitriptyline and nortriptyline in plasma, with use of a nitrogen detector.

1976 ◽  
Vol 22 (6) ◽  
pp. 777-781 ◽  
Author(s):  
D N Bailey ◽  
P I Jatlow
Keyword(s):  
Simultaneous Determination ◽  
Human Plasma ◽  
Chromatographic Analysis ◽  
Active Metabolite ◽  
Internal Standard ◽  
Isoamyl Alcohol ◽  
Coefficients Of Variation ◽  
Chromatographic Procedure ◽  
Therapeutic Doses

Abstract We describe a gas-chromatographic procedure for the simultaneous determination of amitriptyline and its active metabolite, nortriptyline, in therapeutic concentrations in human plasma, with use of a nitrogen detector. Both drugs are extracted at pH 10.5 into hexane/isoamyl alcohol, back-extracted into dilute HCl, and re-extracted into hexane/isoamyl alcohol after alkalinization of the HCl. The solvent is evaporated and the residue gas-chromatographed. Protriptyline is used as the internal standard. As little as 5 mug of amitriptyline or nortriptyline can be detected per liter of plasma. The coefficients of variation, for a concentration of 200 mug/liter, are 4.6% and 4.3% within-day and 8.6% and 3.4% day-to-day for amitriptyline and nortriptyline, respectively. The procedure was applied to patients receiving therapeutic doses of both drugs and also to patients who had taken overdoses of amitriptyline.

Monitoring clorazepate dipotassium as desmethyldiazepam in plasma by electron-capture gas--liquid chromatography.

1980 ◽  
Vol 26 (1) ◽  
pp. 142-144
Author(s):  
D Haidukewych ◽  
E A Rodin ◽  
R Davenport
Keyword(s):  
Liquid Chromatography ◽  
Electron Capture ◽  
Active Metabolite ◽  
Internal Standard ◽  
Gas Liquid Chromatography ◽  
Sensitivity Limit ◽  
One Step ◽  
The Mean ◽  
Pharmacologically Active ◽  
State Concentration

Abstract We describe a procedure for determing clorazepate dipotassium as its decarboxylated, pharmacologically active metabolite, desmethyldiazepam, in 100 microL of plasma, with use of electron-capture gas--liquid chromatography and with methylnitrazepam as the internal standard. The procedure is a one-tube, one-step extraction without derivative formation and is accurate, reproducible, and rapid. The sensitivity limit is 20 micrograms/L. Within-run and between-run CV's (concentration, 3.5 mg/L) were 2.9 and 3.5%, respectively. Within-run CV's for 1.5 and 1.0 mg/L concentrations were 3.9 and 4.3%, respectively. For a 1.0 mg/kg per day dose of clorazepate dipotassium, the mean steady-state concentration of desmethyldiazepam in plasma was 1.037 mg/L.

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