scholarly journals Comparison of LC-MS Assay and HPLC Assay of Busulfan in Clinical Pharmacokinetics Studies

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Hongxia Lin ◽  
Susan Goodin ◽  
Roger K. Strair ◽  
Robert S. DiPaola ◽  
Murugesan K. Gounder
Keyword(s):  
Sample Preparation ◽  
Pharmacokinetic Model ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Pharmacokinetic Parameters ◽  
Precolumn Derivatization ◽  
Hplc Assay ◽  
Clinical Pharmacokinetics ◽  
Liquid Liquid Extraction ◽  
Assay Precision

Busulfan is used in preparative regimens for bone marrow transplantation and timely busulfan plasma concentration reporting is critical for subsequent dose adjustment. We compared two sensitive methods for pharmacokinetics studies including LC-MS assay and HPLC precolumn derivatization assay. Chromatographic separation was performed on a Gemini C18 column. Liquid-liquid extraction with ethyl acetate was used for plasma sample preparation. Busulfan and internal standard ([2H8]-busulfan) were detected as ammonium adducts at m/z 264.2 and 272.2 for LC-MS assay. For HPLC assay, the extraction from plasma was derivatized with 2-naphathalenethiol using synthesized internal standard (1,6-(methanesulfonyloxy)octane). The Ex and Em wavelength was 255 nm and 370 nm. The limit of detection was 15.6 ng/mL and 7.8 ng/mL for HPLC and LC-MS assay and good linearity ranging from 31.25–1000 ng/mL for HPLC and 15.6-1000 ng/mL for LC-MS assay. The intra and interday assay precision were less than 9.2% and 12.0% for LC-MS and HPLC assay. The pharmacokinetic parameters were estimated using noncompartmental pharmacokinetic model with WinNonlin. Busulfan AUClast showed an average difference of 0.7% between the two methods. The LC-MS method is accurate, reproducible, and requires less specimen, sample preparation and analysis time over the HPLC assay, making busulfan monitoring faster and easier in clinical practice.

Determination of Free Solanesol Levels in Cigarette Filters by Liquid Chromatography–Mass Spectrometry

2021 ◽  
Author(s):  
Roberto Bravo Cardenas ◽  
Phuong Ngac ◽  
Clifford Watson ◽  
Liza Valentin-Blasini
Keyword(s):  
Liquid Chromatography ◽  
Sample Preparation ◽  
Tobacco Smoke ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Filter Material ◽  
Previous Method ◽  
Tobacco Smoke Exposure ◽  
Triple Quadrupole Mass Spectrometer ◽  
Cigarette Butts

Abstract Solanesol, a naturally occurring constituent of tobacco, has been utilized as a good marker for environmental tobacco smoke particulate and as a noninvasive predictor of mainstream cigarette smoke tar and nicotine intake under naturalistic smoking conditions. A fast and accurate method for measuring free solanesol to assess tobacco smoke exposure is highly desirable. We have developed and validated a new environmentally friendly, high-throughput method for measuring solanesol content in discarded cigarette filter butts. The solanesol deposited in the used filters can be correlated with mainstream smoke deliveries of nicotine and total particle matter to estimate constituent delivery to smokers. A portion of filter material is removed from cigarette butts after machine smoking, spiked with internal standard solution, extracted and quantitatively analyzed using reverse-phase liquid chromatography coupled to a triple-quadrupole mass spectrometer. The new method incorporates a 48-well plate format for automated sample preparation that reduces sample preparation time and solvent use and increases sample throughput 10-fold compared to our previous method. Accuracy and precision were evaluated by spiking known amounts of solanesol on both clean and smoked cigarette butts. Recoveries exceeded 93% at both low and high spiking levels. Linear solanesol calibration curves ranged from 1.9 to 367 µg/butt with a 0.05 µg/butt limit of detection.

scholarly journals Investigation of Pharmacokinetic Parameters of Trelagliptin in Egyptian Volunteers Using Sensitive LC-MS/MS: A Comparative Study with a Japanese Population

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Shereen Mowaka ◽  
Nermeen Ashoush ◽  
Mariam M. Tadros ◽  
Bassam M. Ayoub
Keyword(s):  
Human Plasma ◽  
Pharmacokinetic Study ◽  
Biological Fluids ◽  
Internal Standard ◽  
Pharmacokinetic Parameters ◽  
Antidiabetic Drug ◽  
Liquid Liquid Extraction ◽  
Direct Precipitation ◽  
Structure Similarity

Trelagliptin (TLN) is a novel once-weekly antidiabetic drug that enhanced the patient compliance in type 2 diabetes. TLN analysis and bioanalysis literature review showed many methods for TLN assay either in dosage form or as biological fluids (pharmacokinetic parameters), but all those methods did not consider the full details dealing with biological assay of TLN. Studies that included information about pharmacokinetic parameters did not mention the used analytical procedures for those determinations and parameters. Although some LC-MS/MS and UPLC-UV methods were reported for TLN bioassay in rats’ plasma, they used direct precipitation techniques, and the current described procedure showed lower LLOQ than all the reported methods in spite of that working on human plasma is more complicated than on rats’ plasma. In this study, LC-MS/MS bioanalysis of TLN in human plasma (4–1000 nM) was employed successfully with LLOQ of 4 nM which is lower than all reported methods in rats’ plasma followed by a preliminary pharmacokinetic study. Alogliptin was used as internal standard (IS) because of its structure similarity to TLN. Pharmacokinetic parameters of TLN were investigated in Egyptian volunteers, and they had been compared to Japanese. Liquid-liquid extraction showed more sensitive results than direct precipitation. The proposed method was successfully applied to a pharmacokinetic study conducted on Egyptian volunteers. No dose modification is required upon comparing the pharmacokinetic parameters of the current study and previous studies on non-Egyptian volunteers.

Sensitive and Selective Liquid-Chromatographic Assay of Fluoxetine and Norfluoxetine in Plasma with Fluorescence Detection After Precolumn Derivatization

1992 ◽  
Vol 38 (9) ◽  
pp. 1756-1761 ◽  
Author(s):  
R F Suckow ◽  
M F Zhang ◽  
T B Cooper
Keyword(s):  
Fluorescence Detection ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Reversed Phase ◽  
Pharmacokinetic Studies ◽  
Precolumn Derivatization ◽  
Ionization Mass ◽  
Ionization Mass Spectroscopy ◽  
Positive Chemical Ionization ◽  
Liquid Chromatographic

Abstract We determined fluoxetine (Prozac) and its major metabolite norfluoxetine in plasma by liquid chromatography with fluorescence detection. After liquid-liquid extraction from 1 mL of plasma, the extract was derivatized at room temperature with dansyl chloride, and the highly fluorescent derivatives were chromatographed with a reversed-phase C18 column and a mobile phase of phosphate buffer and acetonitrile. Dansylated fluoxetine, norfluoxetine, and the internal standard were eluted in less than 14 min with no interference from endogenous material. The calibration curve was linear over the concentration range 25-800 micrograms/L with inter- and intra-assay imprecision (CV) of less than 10%. Validity of the assay was checked by comparing results for 110 patients' samples with those by a liquid-chromatographic method with ultraviolet detection (r = 0.993 for fluoxetine, 0.957 for norfluoxetine). The identity of the dansylated derivatives was verified by positive chemical ionization mass spectroscopy. The lower limit of detection was approximately 3 micrograms/L. Because no major antidepressant, neuroleptic, or respective drug metabolites interfere with the quantification of fluoxetine and norfluoxetine, this is a useful procedure for pharmacokinetic studies and in clinical settings.

scholarly journals DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR THE DETERMINATION OF ALVIMOPAN IN RAT PLASMA

2018 ◽  
Vol 10 (10) ◽  
pp. 124
Author(s):  
Devi Ramesh ◽  
Mohammad Habibuddin
Keyword(s):  
Method Development ◽  
Internal Standard ◽  
The United States ◽  
Hplc Method ◽  
Liquid Extraction ◽  
Pharmacokinetic Parameters ◽  
Dihydrogen Phosphate ◽  
Liquid Liquid Extraction ◽  
Validation Parameters

Objective: The present investigation demonstrates a simple, sensitive and accurate high pressure liquid chromatographic (HPLC) method for the determination of alvimopan (AMP) in rat plasma.Methods: The chromatographic separation was achieved within 10 min by using acetonitrile: potassium dihydrogen phosphate buffer pH 3.0 adjusted with orthophosphoric acid (50:50) as mobile phase on Altima Grace Smart C-18 column (5μ; 250 × 4.6 mm) at a flow rate of 1.0 ml/min with injection volume 50 µl. The drug was extracted from plasma by liquid-liquid extraction using a mixture of methanol: acetonitrile (50:50) as a solvent. The retention times of drug and internal standard were found to be 5.17 and 6.74 min, respectively. This method was validated as per the United States Food and Drug Administration (US-FDA) guidelines.Results: The results of the validation parameters were found to be within the acceptance limits. The method was linear in the concentration range from 5-1000 ng/ml (r2= 0.9998), and the extraction recovery was found to be 78.71±3.86% for AMP. The lower limit of quantification was found to be 5ng/ml, and the stability of recovered samples at different conditions was found to be more than 95%.Conclusion: The developed method possess good selectivity, specificity, there was no interference found in the plasma blanks at retention times of AMP and Internal Standard (IS). We found a good correlation between the peak area and concentration of the drug under prescribed conditions. Furthermore, the method can also be used to estimate the pharmacokinetic parameters of AMP.Keywords: Alvimopan, Liquid-liquid extraction, Method development, Matrix effect, Plasma, Recovery, Stability, Validation

scholarly journals Development and Validation of a LC/MS/MS Method for the Determination of Duloxetine in Human Plasma and Its Application to Pharmacokinetic Study

2012 ◽  
Vol 9 (2) ◽  
pp. 899-911 ◽  
Author(s):  
D. Chandrapal Reddy ◽  
A. T. Bapuji ◽  
V. Surayanarayana Rao ◽  
V. Himabindu ◽  
D. Rama Raju ◽  
...  
Keyword(s):  
Human Plasma ◽  
Multiple Reaction Monitoring ◽  
Internal Standard ◽  
Pharmacokinetic Parameters ◽  
Liquid Liquid Extraction ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Edta Plasma ◽  
Development And Validation

A selective, high sensitive and high throughput liquid chromatography-tandem mass spectrometry (LC-ESI-MS/MS) method has been developed and validated for the chromatographic separation and quantitation of duloxetine in human EDTA plasma using fluoxetine (IS) as an internal standard. Analyte and IS were extracted from human plasma by liquid-liquid extraction using MTBE-n Hexane (80:20).The eluted samples were chromatographed on X-terra RP8 (50 mmx4.6 mm, 5 μm particle size) column by using mixture of 30 mM ammonium formate (pH-5.0±0.05) and acetonitrile as an isocratic mobile phase at a flow rate of 0.40 mL/min and analyzed by mass spectrometer in the multiple reaction monitoring (MRM) using the respective m/z 298.08→154.0 for duloxetine and 310.02→148.07 for IS. The linearity of the response/ concentration curve was established in human plasma over the concentration range 0.100-100.017 ng/mL. The lower detection limit (LOD,S/N>3) was 0.04 ng/mL and the lower limit of quantization (LOQ,S/N>10) was 0.100 ng/mL. This LC-MS/MS method was validated with Intra-batch and Inter-batch precision of 5.21-7.02. The Intra-batch and Inter-batch accuracy was 97.14-103.50 respectively. Recovery of duloxetine in human plasma is 80.31% and ISTD recovery is 81.09%. The main pharmacokinetic parameters were Tmax(hr) = (7.25±1.581), Cmax(ng/mL) (44.594±18.599), AUC0→t, = (984.702±526.502) and AUC0→∞, (1027.147±572.790) respectively.

scholarly journals Determination of Sulfonamide Residues in the Tissues of Food Animals Using Automated Precolumn Derivatization and Liquid Chromatography with Fluorescence Detection

2004 ◽  
Vol 87 (5) ◽  
pp. 1264-1268 ◽  
Author(s):  
Craig D C Salisbury ◽  
Jason C Sweet ◽  
Roger Munro
Keyword(s):  
Liquid Chromatography ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Official Method ◽  
Precolumn Derivatization ◽  
Sample Extract ◽  
Liver And Kidney ◽  
Food Animals ◽  
Sulfonamide Residues

Abstract A liquid chromatographic method for the determination of sulfachloropyridazine, sulfadiazine, sulfadimethoxine, sulfadoxine, sulfaethoxypyridazine, sulfamethazine, sulfaquinoxaline, and sulfathiazole residues in the muscle, liver, and kidney of food animals using sulfapyridine as internal standard is reported. Tissues are extracted using a modified version of AOAC Official Method 983.31 (Sulfonamide Residues in Animal Tissues). The sample extract is reconstituted in pH 3.0 buffer–acetonitrile (60 + 40) and filtered into an autosampler vial. Using a programmable autosampler of a liquid chromatograph, a portion of the sample is derivatized precolumn with fluorescamine. The sulfonamide derivatives are separated by liquid chromatography using a C18 column with a mobile phase of 0.02M phosphoric acid–acetonitrile (60.5 + 39.5) and detected by fluorescence (excitation, 405 nm; emission, 495 nm). The method was applied to swine and cattle muscle, liver, and kidney; sheep and horse muscle and kidney; and chicken muscle and liver. The mean values for samples fortified with sulfonamides at levels between 0.05 and 0.2 μg/g agreed within 96–99% of spiked levels, with coefficients of variation ranging from 4–10%. The limit of detection (LOD) for all sulfonamides was 0.01 μg/g, with the exception of sulfaquinoxaline, for which the LOD was 0.015 μg/g.

scholarly journals Development of a Real-Time PCR Assay for Identification of Coccidioides immitis by Use of the BD Max System: TABLE 1

2015 ◽  
Vol 53 (3) ◽  
pp. 926-929 ◽  
Author(s):  
Marilyn Mitchell ◽  
Dominic Dizon ◽  
Robert Libke ◽  
Michael Peterson ◽  
David Slater ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Hospital Setting ◽  
Internal Standard ◽  
Specimen Preparation ◽  
Coccidioides Immitis ◽  
Rt Pcr ◽  
Content Type

Rapid real-time PCR (RT-PCR) can be performed in a community hospital setting to identifyCoccidioidesspecies using the new Becton Dickinson molecular instrument BD Max. Following sample preparation, DNA extraction and PCR were performed on the BD Max using the BD Max extraction kit ExK-DNA-1 test strip and a master mix prepared by BioGX (Birmingham, AL). Sample preparation took 2 h, and testing on the BD Max took an additional 2 h. Method sensitivity and specificity were evaluated along with the limits of detection to confirm that this convenient method would provide medically useful information. Using serial dilutions, the lower limit of detection was determined to be 1 CFU/μl. Testing with this method was validated using samples from various body sites, including bronchial alveolar lavage (BAL) fluid; sputum and lung tissue samples; and pleural and spinal fluids. Safety protocols were established, and specimen preparation processes were developed for the various types of specimens. The range for the cycle threshold (CT) indicating adequate fluorescent signal to signify a positive result was established along with the acceptable range for the internal standard. Positive controls run with each batch were prepared by spiking a pooled BAL fluid specimen with a known dilution ofCoccidioides immitisorganism. Our experience with testing >330 patient samples shows that clinically relevant information can be available within 4 h using an RT-PCR method on the BD Max to identifyCoccidioidesspp., with sensitivity equivalent to culture.

scholarly journals Determination of Mitotane (DDD) and Principal Metabolite by a Simple HPLC-UV Method and Its Validation in Human Plasma Samples

Separations ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 63
Author(s):  
Giacomo Luci ◽  
Federico Cucchiara ◽  
Laura Ciofi ◽  
Francesca Mattioli ◽  
Marianna Lastella ◽  
...  
Keyword(s):  
Renal Carcinoma ◽  
Limit Of Detection ◽  
Plasma Concentrations ◽  
Internal Standard ◽  
Point Of View ◽  
Therapeutic Drug ◽  
Plasma Samples ◽  
Liquid Liquid Extraction ◽  
Calibration Samples

Mitotane (DDD) is prescribed in adrenocortical renal carcinoma. Its principal metabolite, dichlorodiphenylethene (DDE), can accumulate in fat tissues and from a toxicological point of view, is probably more interesting than the other metabolite dichlorodiphenylacetate (DDA). Therapeutic Drug Monitoring (TDM) of DDD plasma concentrations is required to combine therapeutic efficacy with acceptable toxicity. Therefore, we developed a simple and fast HPLC-UV method to monitor plasma concentrations after a liquid–liquid extraction of plasma calibration samples, quality controls, and anonymous plasma samples with unknown DDD and DDE concentrations. Samples were injected into an HPLC instrument and peaks of mitotane (DDD), DDE and aldrin (internal standard, IS) were resolved by a stationary phase C18 column (250 mm × 4.6 mm, 5 μm), maintained at 35 °C. Mobile phase, made by water/acetonitrile (10/90, v/v), was pumped at a flow of 1.0 mL/min, and absorbance was monitored at a wavelength of 226 nm. Average recovery was 95% for all analytes, and the method was linear for both DDD (r2 = 0.9988, range 1–50 mg/L) and DDE (r2 = 0.9964, range 1–40 mg/L). The values of limit of detection and quantitation were 0.102 and 0.310 mg/L for DDD and 0.036 and 0.108 mg/L for DDE, respectively. The retention time values of DDD, DDE and IS were 7.06, 9.42 and 12.60 min, respectively. The method was successfully validated according to FDA guidelines and finally adopted for routine TDM.

scholarly journals Validation of HPLC and Liquid-Liquid Extraction Methods for Warfarin Detection in Human Plasma and its Application to a Pharmacokinetics Study

2019 ◽  
Vol 12 ◽  
pp. 1-10
Author(s):  
Yung An Chua ◽  
Wan Zaidah Abdullah ◽  
Zurkurnai Yusof ◽  
Siew Hua Gan
Keyword(s):  
Human Plasma ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Liquid Extraction ◽  
Array Detector ◽  
Good Precision ◽  
Buffer Solution ◽  
Limit Of Quantification ◽  
Liquid Liquid Extraction ◽  
Pharmacokinetics Study

A reversed-phase HPLC method to determine total plasma warfarin was developed and validated. Warfarin was extracted from human plasma using a two-step liquid-liquid extraction method. The residue was reconstituted with a phenylbutazone standard solution, which was used as the internal standard. The analytical column was a Purospher STAR RP-18e (4 x 4mm I.D., 5m particle size). The mobile phase consisted of acetonitrile: potassium dihydrogen orthophosphate buffer solution at pH 6.5 [30:70 (v/v)] with a flow rate of 1mL/min. Both warfarin and phenylbutazone were detected using a photodiode array detector. The lower limit of quantification was 100ng/mL, while the limit of detection was 20ng/mL. The linearity of the assay was good (r2=0.992) in the concentration range from 0.1 - 6.0µg/mL. The extraction recovery of warfarin was 93.53 ± 12.40%. Both the intraday and interday quality control assay for warfarin demonstrated good precision and accuracy, with all of the percentage coefficients of variation being less than 15%. Warfarin was stable in human plasma for up to three months of storage. The validated method was successfully applied to four human samples for a pharmacokinetics study.

scholarly journals Determination of Genotoxic Azide Impurity in Cilostazol API by Ion Chromatography with Matrix Elimination

Separations ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 162
Author(s):  
Boglárka Páll ◽  
Zsuzsa Gyenge ◽  
Róbert Kormány ◽  
Krisztián Horváth
Keyword(s):  
Sample Preparation ◽  
Ion Chromatography ◽  
Sodium Azide ◽  
Limit Of Detection ◽  
Active Pharmaceutical Ingredient ◽  
Liquid Extraction ◽  
Limit Of Quantification ◽  
Positive Effects ◽  
Liquid Liquid Extraction

Cilostazol is a commonly used active pharmaceutical ingredient (API) to treat and reduce the symptoms of intermittent claudication in peripheral vascular disease. Recently, it was found to be a potential medicine in the effective treatment of COVID-19. In addition to the positive effects of this API, genotoxic sodium azide is used in the synthesis of cilostazol that can appear in the API. In this work, a method was developed for the determination of sodium azide (as azide anion) in cilostazol API at 7.5 ppm limit level by using ion chromatography (IC) and liquid–liquid extraction (LLE) sample preparation. The liquid–liquid extraction allows the application of high sample concentrations. Because of the low limit concentration (7.5 ppm), 500 mg sample was dissolved in 5 mL solvent. By using LLE for sample preparation, the huge amount of cilostazol was omitted and column overload was avoided. The developed method was validated in accordance with the relevant guidelines. Specificity, accuracy, precision, limit of detection and limit of quantification parameters were evaluated. The calculated limit of detection was 0.52 ppm (S/N:3) and the limit of quantification was 1.73 ppm (S/N:10) for sodium azide. The recovery of the sodium azide was 102.4% and the prepared solutions were stable in the sample holder for 24 h.

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