scholarly journals Quantification of Teicoplanin Using the HPLC-UV Method for Clinical Applications in Critically Ill Patients in Korea

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 572
Author(s):  
Jaeok Lee ◽  
Eun-Kyoung Chung ◽  
Sung-Wook Kang ◽  
Hwa-Jeong Lee ◽  
Sandy-Jeong Rhie
Keyword(s):  
High Performance ◽  
Internal Standard ◽  
Polymyxin B ◽  
Therapeutic Drug ◽  
Ultraviolet Detector ◽  
Wide Range ◽  
External Standard ◽  
Analytical Accuracy ◽  
Trough Concentrations ◽  
Improved Accuracy

A high-performance liquid chromatography-ultraviolet detector (HPLC-UV) method has been used to quantify teicoplanin concentrations in human plasma. However, the limited analytical accuracy of previously bioanalytical methods for teicoplanin has given rise to uncertainty due to the use of an external standard. In this study, an internal standard (IS), polymyxin B, was applied to devise a precise, accurate, and feasible HPLC-UV method. The deproteinized plasma sample containing teicoplanin and an IS of acetonitrile was chromatographed on a C18 column with an acidic mobile phase consisting of NaH2PO4 buffer and acetonitrile (78:22, v/v) by isocratic elution and detection at 220 nm. The linearity was in the range 7.8–500 mg/L calculated by the ratio of the teicoplanin signal to the IS signal. This analytical method, validated by FDA guidelines with ICH Q2 (R1), was successfully applied to analyze the plasma samples of patients in the intensive care unit for treating serious resistant bacterial infectious diseases, such as those by methicillin-resistant Staphylococcus aureus and Enterococcus faecalis. The methods suggested the potential for use in routine clinical practice for therapeutic drug monitoring of teicoplanin, providing both improved accuracy and a wide range of linearity from lower than steady-state trough concentrations (10 mg/L) to much higher concentrations.

High-Performance Liquid Chromatographic Determination of Memantine in Human Urine Following Solid-Phase Extraction and Precolumn Derivatization

2013 ◽  
Vol 96 (6) ◽  
pp. 1302-1307 ◽  
Author(s):  
Karim Michail ◽  
Hoda Daabees ◽  
Youssef Beltagy ◽  
Magdy Abd Elkhalek ◽  
Mona Khamis
Keyword(s):  
Human Urine ◽  
High Performance ◽  
Solid Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Therapeutic Drug ◽  
Time Interval ◽  
Precolumn Derivatization ◽  
Uv Detector

Abstract A validated HPLC-UV method is presented for the quantification of urinary memantine hydrochloride, a novel medication approved to treat moderate and advanced cases of Alzheimer's disease. The drug and amantadine hydrochloride, the internal standard, were extracted from human urine using SPE. The extract was then buffered and derivatized at room temperature using o-phthalaldehyde in the presence of N-acetyl-L-cyteine. Chromatographic separation of the formed derivatives was achieved on a C18 column using methanol–water mobile phase adjusted to pH 7 and pumped isocratically at 1 mL/min. The UV detector was set at 340 nm. The chromatographic run time did not exceed 10 min. The LOD and LOQ were 8 and 20 ng/mL, respectively. The RSDs for intraday and interday precisions did not exceed 5.5%. The method was used to monitor memantine hydrochloride in human urine in order to determine an appropriate sampling interval for future noninvasive therapeutic drug monitoring. The assay could also be applied to the determination of amantadine. The described assay showed that a postdosing time interval of 25–75 h seems adequate for sampling and monitoring memantine in urine.

Liquid-chromatographic measurement of nitrazepam in plasma.

1982 ◽  
Vol 28 (7) ◽  
pp. 1478-1481 ◽  
Author(s):  
H Kelly ◽  
A Huggett ◽  
S Dawling
Keyword(s):  
Complete Resolution ◽  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Small Sample ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Method ◽  
Chromatographic Measurement ◽  
The Stability ◽  
Liquid Chromatographic

Abstract In this simple and rapid "high-performance" liquid-chromatographic method for determining nitrazepam in plasma, serum, or whole blood, the sample at pH 7.4 is extracted into diethyl ether with an internal standard (prazepam), chromatographed, and detected at 280 nm with a fixed-wavelength ultraviolet detector. A specimen, together with standards and a quality control, can be analyzed in duplicate within 90 min. The limit of sensitivity is 5 micrograms/L (nitrazepam and 7-acetamidonitrazepam) and 50 micrograms/L (7-aminonitrazepam), and no interferents have been found. This method has the advantages of a small sample requirement and complete resolution of nitrazepam and the above-mentioned major metabolites. We have used this method for analysis of therapeutic and overdose concentrations of nitrazepam, and to investigate the stability of the drug in blood.

Analysis of Fat-Soluble Vitamins. XXIII. High Performance Liquid Chromatographic Assay for Vitamin D in Vitamin D3 and Multivitamin Preparations1

1979 ◽  
Vol 62 (6) ◽  
pp. 1285-1291
Author(s):  
Ellen J De Vries ◽  
Jakob Zeeman ◽  
Robert J E Esser ◽  
Ben Borsje ◽  
Frits J Mulder
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Coefficient Of Variation ◽  
High Performance ◽  
Conversion Factor ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
External Standard ◽  
Fat Soluble Vitamins ◽  
Liquid Chromatographic

Abstract Vitamin D is determined in preparations containing other fat-soluble vitamins by high performance liquid chromatography (HPLC). The unsaponifiable residue is extracted and separated from interferences by reverse phase chromatography; the fraction corresponding to vitamin D3 is collected and quantitated using normal phase chromatography (amylalcohol-n-hexane as mobile phase) by measuring the vitamin D3 and previtamin D3 peaks at 254 nm. Previtamin D3 content is calculated as vitamin D3 with a conversion factor (determined on the equipment used). Application of the method to vitamin AD3 mixtures in oils gives 98-102% recovery. The reproducibility, using an external standard, is 2-3%, calculated as the coefficient of variation; with an internal standard, the coefficient of variation is 1-1.5%. The method measures potential vitamin D3 content in preparations containing ≽ 200 IU/g in the presence of all known vitamin D3 isomers, vitamin A, and vitamin E.

Measurement of branched chain amino acids in blood plasma by high performance liquid chromatography

1988 ◽  
Vol 66 (5) ◽  
pp. 613-617 ◽  
Author(s):  
Line Robitaille ◽  
L. John Hoffer
Keyword(s):  
Amino Acids ◽  
High Performance ◽  
Internal Standard ◽  
Ammonium Hydroxide ◽  
Ion Exchange Resin ◽  
Branched Chain Amino Acids ◽  
Chromatographic Technique ◽  
Automatic Amino Acid Analyzer ◽  
Ultraviolet Detector ◽  
Branched Chain

A simple and rapid high performance liquid chromatographic technique is described for the separation and quantitation of plasma branched chain amino acids. After addition of a norleucine internal standard, plasma samples are acidified with acetic acid, and amino acids are separated from proteins and other plasma components by passage of the acidified plasma through an ion exchange resin. The ammonium hydroxide eluate from the resin is dried, phenylisothiocyanate derivatives are prepared, and the amino acids are separated on a Waters reverse-phase "Pico-Tag" column with an ultraviolet detector set at 254 nm. In addition to the branched chain amino acids (leucine, valine, and isoleucine), aspartate, glutamate, serine, threonine, alanine, and methionine are quantitated with high precision and accuracy, as verified by quantitative recovery and comparison with an automatic amino acid analyzer. The advantages of the method are its simplicity, speed, stability of derivatives, high reproducibility, low per-sample cost, and the use of a simple fixed-wavelength ultraviolet detector.

Determination of Fenofibric Acid in Rat Plasma and its Application to a Comparative Pharmacokinetic Study of JW322 and Fenofibrate

Drug Research ◽  
2017 ◽  
Vol 67 (09) ◽  
pp. 534-538
Author(s):  
Tae Kim
Keyword(s):  
High Performance ◽  
Internal Standard ◽  
Relative Bioavailability ◽  
Rat Plasma ◽  
Reversed Phase ◽  
Pharmacokinetic Parameters ◽  
Fenofibric Acid ◽  
Ultraviolet Detector ◽  
Quantitation Limit

AbstractIn this study, a sensitive and reliable method for the quantitation of fenofibric acid in rat plasma was developed and validated using high performance liquid chromatography (HPLC). The plasma samples were prepared by deproteinization, and sildenafil was used as an internal standard. Chromatographic separation was achieved using a reversed-phase (C18) column. The mobile phase, 0.02 M ammonium acetate buffer:acetonitrile (35:65, v/v), was run at a flow rate of 1.0 mL/min, and the column eluent was monitored using an ultraviolet detector at 280 nm at room temperature. The retention times of sildenafil (an internal standard), and fenofibric acid were approximately 5.9 and 7.7 min, respectively. The quantitation limit of fenofibric acid in rat plasma was 0.03 μg/mL. Pharmacokinetic parameters of fenofibric acid was evaluated after oral (at doses of 20 mg/kg) administration of JW322 and fenofibrate in rats. After oral administration (20 mg/kg) of JW322, relative bioavailability was approximately 272.8% compared to fenofibrate.

scholarly journals Measurement of Aldosterone in Human Plasma by Semiautomated HPLC–Tandem Mass Spectrometry

2009 ◽  
Vol 55 (6) ◽  
pp. 1155-1162 ◽  
Author(s):  
Paul J Taylor ◽  
Donald P Cooper ◽  
Richard D Gordon ◽  
Michael Stowasser
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Human Plasma ◽  
High Performance ◽  
Internal Standard ◽  
Tandem Mass ◽  
Limit Of Quantification ◽  
Analytical Recovery ◽  
Wide Range ◽  
Edta Plasma

Abstract Background: Reliable measurement of aldosterone with less interlaboratory variation than RIA would help standardize testing for primary aldosteronism. We set out to validate a high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) method for aldosterone in human plasma. Methods: We prepared samples (EDTA plasma, lithium heparin plasma, and serum from separator and plain clot tubes) and measured aldosterone using online HPLC-MS/MS with d7-aldosterone as internal standard. We also analyzed EDTA plasma samples by immunoassay. We established a reference range for HPLC-MS/MS aldosterone by analyzing blood collected midmorning from 97 normotensive seated subjects. Results: The linear range was 69.4–5548.0 pmol/L (2.5–200 ng/dL) (r2 > 0.994, n = 14). Inter- and intraday analytical recovery and imprecision for quality control samples of 166.4, 1109.6, and 4161.0 pmol/L (6.0, 40.0, and 150.0 ng/dL) were 92.2%–102.0% and <6.3%, respectively (n = 5). The lower limit of quantification was 69.4 pmol/L (2.5 ng/dL), with inter- and intraday analytical recovery and imprecision of 91.4%–94.5% and <9.5% (n = 5). No interferences were observed in plasma from Addison’s disease patients (n = 5). Comparison of collection tubes, using EDTA as the reference, revealed similar aldosterone results. Comparison of HPLC-MS/MS with immunoassay gave an acceptable mean bias (0.83%) but wide range (−44.8% to 39.7%) of differences. HPLC-MS/MS aldosterone concentrations in normotensive subjects ranged from <69.4 to 635.2 pmol/L (<2.5 to 22.9 ng/dL). Conclusions: This first reported aldosterone method using online HPLC-MS/MS is precise across the clinically relevant range, not influenced by collection tube type, and offers semiautomated sample preparation and high throughput.

scholarly journals DETERMINATION OF TERIFLUNOMIDE ACROSS A WIDE DYNAMIC CONCENTRATION RANGE IN HUMAN PLASMA BY LC–MS/MS

2019 ◽  
Vol 16 (32) ◽  
pp. 608-620
Author(s):  
Natalia E. MOSKALEVA ◽  
Natalia V. MESONZHNIK ◽  
Roman M. KUZNETSOV ◽  
Pavel A. MARKIN ◽  
Svetlana A. APPOLONOVA
Keyword(s):  
Blood Plasma ◽  
High Performance ◽  
Plasma Concentrations ◽  
Internal Standard ◽  
The Body ◽  
Human Blood Plasma ◽  
Measured Concentration ◽  
Wide Range ◽  
The Difference ◽  
Acquity Uplc

Leflunomide is an antirheumatic drug with anti-inflammatory and antirheumatic properties, it is rapidly metabolized in the body to the active metabolite teriflunomide, which causes its pharmacological activity. At the usual 20-mg daily dosage of leflunomide, the expected teriflunomide plasma concentration is about 35 μg/ml. The pharmacokinetics of the drug is characterized by a large interindividual variability and a long half-life, which in combination with possible side effects creates the need to control the concentration of teriflunomide in the blood plasma. Teriflunomide may increase the risk of fetal death or teratogenic effects when administered to pregnant women. Teriflunomide plasma concentrations less than 0.02 μg/ml are preferred for patients anticipating pregnancy. In this study, a sensitive and high-performance method for analyzing teriflunomide in human blood plasma in a wide range of concentrations was developed and validated using a triple quadrupole liquid chromatography-mass spectrometer (HPLC-MS/MS). Sample preparation was performed by protein precipitation with acetonitrile, followed by chromatographic separation using an Acquity UPLC BEN C8 1.7 mm, 2.1 × 50 mm column (Waters, USA). D4-teriflunomide was used as an internal standard. The developed method was validated in the concentration range from 0.001 μg/ml to 200 μg/ml teriflunomide in plasma. Accuracy (%), defined as the difference between the nominal and measured concentration and reproducibility (coefficient of variation CV) ranged from -5.02% to 5.00% and from 0.47% to 9.30%, respectively, within the series and between series of samples. The developed method was successfully used to analyze volunteer blood plasma samples after taking 20 mg of leflunomide.

Development and Validation of HPLC and HPTLC Methods for Therapeutic Drug Monitoring of Capecitabine in Colorectal Cancer Patients

2019 ◽  
Vol 57 (10) ◽  
pp. 892-900
Author(s):  
Sonali G Thorat ◽  
Rupesh V Chikhale ◽  
Madhukar R Tajne
Keyword(s):  
Colorectal Cancer ◽  
Therapeutic Drug Monitoring ◽  
Combination Therapy ◽  
Drug Monitoring ◽  
High Performance ◽  
Internal Standard ◽  
Therapeutic Drug ◽  
Chemotherapy Agent ◽  
Assay Methods ◽  
Colorectal Cancer Patients

Abstract Capecitabine is a prodrug of 5-fluorouracil, employed as a monotherapy or combination chemotherapy agent for treatment of colorectal cancer. Combination therapy of capecitabine consists of oxaliplatin, and hence, it becomes essential to determine that co-administration does not affect its metabolism. High-performance liquid chromatography and high-performance thin-layer chromatography methods were developed and validated to determine the plasma concentration of capecitabine. In this study, blood samples from 12 patients with colorectal cancer were collected and analyzed by both methods with a reference internal standard. Two groups consisting of six patients each were formed: the first group was treated with capecitabine monotherapy, the second group with capecitabine + oxaliplatin combination therapy. The results of analysis from both the methods indicated that there is no significant drug–drug interaction. The co-administration of oxaliplatin did not affect the metabolism of capecitabine. Both assay methods were compared for their sensitivity, robustness and specificity. It was found that both the assay methods were suitable for therapeutic drug monitoring of capecitabine.

scholarly journals CYP3A5 Genotype-Dependent Drug-Drug Interaction Between Tacrolimus and Nifedipine in Chinese Renal Transplant Patients

2021 ◽  
Vol 12 ◽  
Author(s):  
Yilei Yang ◽  
Xin Huang ◽  
Yinping Shi ◽  
Rui Yang ◽  
Haiyan Shi ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Renal Transplant ◽  
High Performance ◽  
Therapeutic Drug ◽  
Transplant Patients ◽  
Cyp3a5 Genotype ◽  
Group I ◽  
Trough Concentrations ◽  
Renal Transplant Patients ◽  
Group Ii

Purpose: The drug-drug interactions (DDIs) of tacrolimus greatly contributed to pharmacokinetic variability. Nifedipine, frequently prescribed for hypertension, is a competitive CYP3A5 inhibitor which can inhibit tacrolimus metabolism. The objective of this study was to investigate whether CYP3A5 genotype could influence tacrolimus-nifedipine DDI in Chinese renal transplant patients.Method: All renal transplant patients were divided into CYP3A5*3/*3 homozygotes (group I) and CYP3A5*1 allele carriers (CYP3A5*1/*1 + CYP3A5*1/*3) (group II). Each group was subdivided into patients taking tacrolimus co-administered with nifedipine (CONF) and that administrated with tacrolimus alone (Controls). Tacrolimus trough concentrations (C0) were measured using high performance liquid chromatography. A retrospective analysis compared tacrolimus dose (D)-corrected trough concentrations (C0) (C0/D) between CONF and Controls in group I and II, respectively. At the same time, a multivariate line regression analysis was made to evaluate the effect of variates on C0/D.Results: In this study, a significant DDI between tacrolimus and nifedipine with respect to the CYP3A5*3 polymorphism was confirmed. In group I (n = 43), the C0/D of CONF was significantly higher than in Controls [225.2 ± 66.3 vs. 155.1 ± 34.6 ng/ml/(mg/kg); p = 0.002]. However, this difference was not detected in group II (n = 27) (p = 0.216). The co-administrated nifedipine and CYP3A5*3/*3 homozygotes significantly increased tacrolimus concentrations in multivariate line regression analysis.Discussion: A CYP3A5 genotype-dependent DDI was found between tacrolimus and nifedipine. Therefore, personalized therapy accounting for CYP3A5 genotype detection as well as therapeutic drug monitoring are necessary for renal transplant patients when treating with tacrolimus and nifedipine.

Within-Patient Atazanavir Trough Concentration Monitoring in HIV-1-Infected Patients

2010 ◽  
Vol 24 (2) ◽  
pp. 216-222 ◽  
Author(s):  
Rustin D. Crutchley ◽  
Qing Ma ◽  
Adel Sulaiman ◽  
Jill Hochreitter ◽  
Gene D. Morse
Keyword(s):  
High Performance ◽  
Clinical Success ◽  
Primary Objective ◽  
Repeated Measurements ◽  
Therapeutic Drug ◽  
Target Values ◽  
Intrapatient Variability ◽  
Trough Concentrations ◽  
Hiv 1 ◽  
Interpatient Variation

Objective: Protease inhibitors (PIs) exhibit considerable interpatient pharmacokinetic variability in plasma trough concentrations. Therapeutic drug monitoring (TDM) is occasionally used to guide chronic dosing to achieve target trough concentrations, but its clinical success assumes minimal intrasubject variability. Therefore, our primary objective was to evaluate intrapatient variability in atazanavir (ATV) plasma trough concentrations in HIV-1-infected patients. Design/Methods: In a single-site, prospective, cohort study, patients on atazanavir with or without ritonavir (ATV/r or ATV) for 2 clinic visits were enrolled. Adherence and time since last dose (TSLD) were verified at each visit. ATV was assayed with high-performance liquid chromatography. Intra- and interpatient variation was evaluated using the median intraindividual percentage coefficient of variation (ICV). Results: The mean 24-hour ATV trough concentrations for the first and second visit for the ATV/r group (n = 10) was 598 (CV 84%) and 525 ng/mL (CV 66%), respectively ( P = .511), and 300 (CV 81%) and 434 ng/mL (CV 106%) for the ATV group (n = 4), respectively ( P = .369). Median ICV was 43.1% for all patients (range: 0.6%-107.6%), 38.1% (0.6%-107.6%) for the ATV/r group, and 33.1% (2.3%-87.6%) for the ATV group. Conclusions: Potential intrapatient variability in ATV troughs suggests that repeated measurements may be required to ensure that target values are maintained.

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