scholarly journals Determination of diazepam and its metabolites in serum by the use of liquid chromatography: Mass spectrometry method

2007 ◽  
Vol 64 (10) ◽  
pp. 659-662 ◽  
Author(s):  
Snezana Djordjevic ◽  
Vesna Kilibarda
Keyword(s):  
Biological Fluids ◽  
Accurate Method ◽  
Reversed Phase ◽  
Active Metabolites ◽  
Serum Samples ◽  
Standard Curve ◽  
Routine Identification ◽  
Selective Ion Monitoring ◽  
Pharmacologically Active

Background/Aim. Diazepam is a benzodiazepine anxyolitic. Metabolism of diazepam takes place in liver which generates pharmacologically active metabolites N-desmethyldiazepam, temazepam and oxazepam. The aim of this study was to develop and validate the method of liquid chromatographymass spectrometry (LC-MS) for separation and determination of diazepam and its active metabolites in the serum of rats samples after i.p. application of diazepam in a dose of 10 mg/kg. Methods. The serum samples taken from Wistar rats, were used in LC-MS analysis after the application of 10 mg/kg of diazepam i.p. Results. After alkaline extraction from the serum samples with diethylether and separation on a C18 reversed-phase column by using mobile phase methanolglacial acetic acid-water (50:1:49 v/v), diazepam and its metabolites were quantified. Determination was performed in a selective ion monitoring (SIM) mode, thereby the other exogenous and endogenous compounds did not interfere with this assay. Diazepam, N-desmethyldiazepam, oxazepam and temazepam were eluted in 14 minutes. The standard curve was linear in the range from 10-2 000 ng/ml. The limits of detection for diazepam, N-desmethyldiazepam, oxazepam and temazepam were 4.37, 3.13, 4.38 and 7.31 ng/ml, respectively. The limits of quantitation for diazepam, Ndesmethyldiazepam, oxazepam and temazepam were 14.58, 10.41, 14.59 and 24.36 ng/ml, respectively. Conclusion. The described LC-MS is a simple, sensitive, specific and accurate method and could be used for routine identification and quantification of small concentrations of diazepam and its metabolites in biological fluids.

Liquid-chromatographic procedure for simultaneous analysis for eight benzodiazepines in serum.

1982 ◽  
Vol 28 (11) ◽  
pp. 2274-2278 ◽  
Author(s):  
G L Lensmeyer ◽  
C Rajani ◽  
M A Evenson
Keyword(s):  
High Performance ◽  
Reversed Phase ◽  
Gradient System ◽  
Active Metabolites ◽  
Reduced Pressure ◽  
Working Standard ◽  
Standard Curve ◽  
Chromatographic Procedure ◽  
Pharmacologically Active ◽  
Liquid Chromatographic

Abstract We describe an efficient extraction and liquid-chromatographic method for separating commonly encountered benzodiazepine drugs and their pharmacologically active metabolites. After a single extraction of the drugs from serum, chlordiazepoxide, demoxepam, N-desmethyl-chloriazepoxide, diazepam, N-desmethyldiazepam, N-desalkylflurazepam, oxazepam, and prazepam can be resolved and quantified by using a C18 reversed-phase "high-performance" column and a ternary-solvent gradient system. Three separate solutions [60 mmol/L ammonium acetate (pH 7.69), 60 mmol/L acetic acid (pH 2.8), and acetonitrile] were incorporated into a gradient mobile phase such that changes in pH and solvent composition occur. Complete chromatographic resolution of the benzodiazepines resulted, permitting quantification of all within 15 min. The standard curve is linear to at least 8 mg/L for each drug, and the detection limit for each was 0.05-0.10 mg/L. The day-to-day precision for both high and low concentrations yielded CVs of 5 to 9%. Extraction of each drug from serum was 95 to 100% complete. Exogenous and endogenous interferences are minimal. Finally, we circumvented the instability problem of benzodiazepine standards in solution by using a simple reduced-pressure drying process that produces a working standard that is stable for at least nine months.

Simultaneous determination of lidocaine and its principal metabolites by liquid chromatography on silica gel, with aqueous eluent.

1984 ◽  
Vol 30 (5) ◽  
pp. 637-640 ◽  
Author(s):  
K Kushida ◽  
K Oka ◽  
T Suganuma ◽  
T Ishizaki
Keyword(s):  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Silica Gel ◽  
High Performance ◽  
Reversed Phase ◽  
Active Metabolites ◽  
Lower Detection ◽  
Pharmacologically Active ◽  
Organic Amines

Abstract We describe the simultaneous determination of lidocaine and its pharmacologically active metabolites, monoethylglycinexylidide and glycinexylidide, in plasma by "high-performance" liquid-chromatography. By use of a bare ( unbonded ) silica gel with aqueous eluents, separations of organic amines such as lidocaine and its metabolites, which are very difficult and have a poor peak symmetry on bonded reversed-phase packings, were easily accomplished with a good peak symmetry. The method is sufficiently precise, sensitive, and specific. Analytical recoveries of all compounds were greater than 90%; CVs for reproducibility were less than 5% for all compounds; the lower detection limits were 0.1 mg/L or less. This method can be used to monitor the concentrations of these compounds in plasma and to prevent the concentration-related side-effect(s).

Development of an HPLC method for measuring orally administered 1-substituted 2-alkyl-3-hydroxypyrid-4-one iron chelators in biological fluids

1990 ◽  
Vol 36 (1) ◽  
pp. 5-8 ◽  
Author(s):  
J G Goddard ◽  
G J Kontoghiorghes
Keyword(s):  
High Performance ◽  
Biological Fluids ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Hplc Method ◽  
Iron Chelators ◽  
Serum Samples ◽  
Thalassemic Patient ◽  
Serum And Urine

Abstract "High-performance" liquid-chromatographic (HPLC) methods have been developed for identifying 1-substituted 2-alkyl-3-hydroxypyrid-4-one iron chelators in serum and urine. Ion pairing with heptane- or octanesulfonic acid in pH 2.0-2.2 phosphate buffer and reversed-phase chromatography were required to separate these compounds from endogenous compounds in both biological fluids. In both the 2-methyl and 2-ethyl series of 1-substituted compounds (H, methyl, ethyl, or propyl) the elution times increased in accordance with the n-octanol/water partition coefficients (propyl greater than ethyl greater than H greater than methyl). Urine samples were filtered (0.4 microns pore size) and injected either undiluted or after dilution with elution buffer. After the addition of internal standard, the plasma or serum samples were deproteinized by treatment with HCIO4, 0.5 mol/L, centrifuged, and the supernates were injected directly onto the HPLC. Using these procedures, we could identify 1,2-dimethyl-3-hydroxypyrid-4-one (L1) in the serum and urine of a thalassemic patient who had received a 3-g dose of the drug and in the urine of other patients who had received the same dose. One or more possible metabolites were also observed in the chromatograms of both urine and serum. The 24-h urinary output of L1 (0.22-2.37 g) and iron (10.6-71.5 mg) varied but there was no correlation between the two with respect to quantity or concentration. Instead, urinary iron output was higher in patients with a greater number of transfused units of erythrocytes. This is the first study in humans to show that L1 is absorbed from the gut, enters the circulation, and is excreted in the urine.

Determination of nifedipine in serum or plasma by reversed-phase liquid chromatography.

1983 ◽  
Vol 29 (7) ◽  
pp. 1344-1348 ◽  
Author(s):  
P R Bach
Keyword(s):  
Liquid Chromatography ◽  
Reversed Phase ◽  
Extraction Column ◽  
Phase Extraction ◽  
Reversed Phase Liquid Chromatography ◽  
Ultraviolet Absorbance ◽  
Standard Curve ◽  
Coefficients Of Variation ◽  
Phase Liquid

Abstract Therapeutic concentrations of nifedipine in serum or plasma were measured by reversed-phase liquid chromatography, with detection by ultraviolet absorbance at 235 nm. In the procedure a disposable reversed-phase extraction column is used. A 1-mL sample is required. The method is sensitive to 3 micrograms of nifedipine per liter and the standard curve is linear to at least 400 micrograms/L. Coefficients of variation at 100 micrograms/L were 2.2% within-run, 2.8% between-run. The method has been used to determine nifedipine in patients involved in a test of its efficacy in treating muscular dystrophy.

scholarly journals Direct Injection Liquid Chromatographic Technique for Simultaneous Determination of Two Antihistaminic Drugs and Their Main Metabolites in Serum

2007 ◽  
Vol 90 (2) ◽  
pp. 384-390 ◽  
Author(s):  
Samy Emara ◽  
Alaa El-Gindy ◽  
Mostafa K Mesbah ◽  
Ghada M Hadad
Keyword(s):  
Human Serum ◽  
Simultaneous Determination ◽  
Chromatographic Technique ◽  
Simple Liquid ◽  
Good Precision ◽  
Active Metabolites ◽  
Serum Samples ◽  
Antihistaminic Drugs ◽  
Liquid Chromatographic

Abstract A very simple liquid chromatographic technique was developed and validated for the simultaneous determination of 2 antihistaminic drugs, loratadine (LT) and terfenadine (TR), and their major active metabolites, desloratadine (DL) and fexofenadine (FX), respectively, in human serum. LT, DL, TR, and FX from directly injected serum samples were enriched on a protein-coated RP8 silica precolumn (10 4.6 mm id) while serum constituents, such as proteins and salts, were eluted to waste. Using an online column-switching system, the drugs and their metabolites were quantitatively transferred and separated on a second analytical column (Shim-pack 5 μm particle size cyanopropyl, 250 × 4.6 mm id) followed by ultraviolet detection at 243 nm for LT and DL and 220 nm for TR and FX. Very good precision, accuracy, and linearity were obtained over the range of 101000 ng/mL for LT and DL, 10500 ng/mL for TR, and 103000 ng/mL for FX in human serum. High extraction recoveries from serum ranging from 96.03 to 98.19, 95.44 to 97.26, 95.61 to 98.17, and 95.60 to 97.89 for LT, DL, TR, and FX, respectively, were obtained.

scholarly journals Detection of pregnancy in sheep using an ELISA for pregnancy-specific protein B

2018 ◽  
Vol 66 (2) ◽  
pp. 329-336
Author(s):  
Tímea Milisits-Németh ◽  
Orsolya Gabriella Balogh ◽  
István Egerszegi ◽  
László Kern ◽  
R. Garth Sasser ◽  
...  
Keyword(s):  
Accurate Method ◽  
Specific Protein ◽  
Economic Benefits ◽  
Seasonal Breeding ◽  
Serum Samples ◽  
Mating Period ◽  
Blood Samples ◽  
Sheep Production ◽  
Protein B

The early detection of pregnancy and the determination of fetal numbers have economic benefits in sheep production because of the seasonal breeding patterns where missing a breeding opportunity means the loss of one productive year. The purpose of this study was to evaluate the efficacy of the B6-HRP ELISA for ovine pregnancy-specific protein B (oPSPB) measurement in the detection of pregnancy and estimation of fetal numbers in different sheep breeds. BioPRYN® ELISA assay kit was used for the detection of pregnancy in the experimental animals. Ninety-three ewes of three breeds (British Milksheep – BM, Lacaune – L and Transylvanian Racka – TR), each from three farms in Hungary, were included in the study. BM and L ewes were artificially inseminated (AI). Thirty-five days after AI, all ewes were examined by transabdominal ultrasound. The TR flock was mated naturally over a six-week period. At the end of the mating period, the ewes were similarly examined by ultrasound. Blood samples were taken from all pregnant ewes twice (35 and 65 days after AI), and serum samples were assayed by the BioPRYN test. It can be concluded that the detection of serum PSPB by ELISA is a much easier, safer, less expensive and highly accurate method for the detection of ovine pregnancy. Although some breed-related differences were detectable at 35 and 65 days post breeding, no differences in oPSPB levels were found in pregnant ewes carrying different numbers of fetuses.

Automated Determination of Fluvoxamine in Plasma by Column-Switching High-Performance Liquid Chromatography

1992 ◽  
Vol 38 (10) ◽  
pp. 2082-2086 ◽  
Author(s):  
S Härtter ◽  
H Wetzel ◽  
C Hiemke
Keyword(s):  
High Performance ◽  
Internal Standard ◽  
Column Switching ◽  
Reversed Phase ◽  
Therapeutic Monitoring ◽  
Detector Response ◽  
Serum Samples ◽  
Automated Method ◽  
Automated Determination

Abstract A column-switching system with high-performance liquid-chromatographic separation and ultraviolet detection is described for automated determination of fluvoxamine in human plasma or serum. Samples were injected and the drug was retained in a clean-up column [20 x 4.6 mm (i.d.)] filled with C8 reversed-phase material (10-micron particles). After unwanted material was washed out, the drug was eluted and separated with an analytical chromatography column, 4.6 x 250 mm (i.d.), filled with Nucleosil 100 CN (5-micron particles) with an acetonitrile:methanol:0.01 mol/L phosphate buffer eluent (188:578:235 by vol) at a flow rate of 1.5 mL/min for < 20 min and detected by spectrometry at 214 nm. With oxaprotiline as internal standard, fluvoxamine could be easily quantified, and it was well separated from endogenous plasma constituents and various psychoactive drugs. The detection limit was 10 micrograms/L (31.6 nmol/L), the analytical recoveries were 97-100%, and the relationship between drug concentration and detector response was linear from 0 to 1000 micrograms/L (3160 nmol/L). The automated method is suitable for therapeutic monitoring of fluvoxamine in the treatment of psychiatric patients.

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