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.

Revival of physostigmine – a novel HPLC assay for simultaneous determination of physostigmine and its metabolite eseroline designed for a pharmacokinetic study of septic patients

2015 ◽  
Vol 53 (8) ◽  
Author(s):  
Nadine Pinder ◽  
Johannes B. Zimmermann ◽  
Stefan Hofer ◽  
Thorsten Brenner ◽  
Markus A. Weigand ◽  
...  
Keyword(s):  
Fluorescence Detection ◽  
Limit Of Detection ◽  
Plasma Concentrations ◽  
Internal Standard ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Pharmacokinetic Studies ◽  
Simple Liquid ◽  
Hplc Assay ◽  
Limit Of Quantification

AbstractPhysostigmine, commonly used as an antidote in anticholinergic poisoning, is reported to have additional pharmacological effects, such as activation of the cholinergic anti-inflammatory pathway in sepsis models. Due to the narrow therapeutic range of physostigmine and its metabolite eseroline, however, the plasma concentrations of these substances need to be determined so as to understand their effect and ensure safety in the treatment of septic patients.To determine physostigmine and its metabolite eseroline, a rapid and sensitive high performance liquid chromatography (HPLC) method has been developed and validated. Spiked plasma samples were cleaned up and concentrated using a simple liquid-liquid extraction (LLE) procedure with N-methylphysostigmine as internal standard. Separation was achieved using reversed-phase HPLC on a Kinetex C18 column with gradient elution and fluorescence detection (254 nm excitation/355 nm emission).LLE produced clean extracts and a mean recovery of 80.3% for eseroline and 84.9% for physostigmine. The HPLC assay revealed a limit of detection (LOD) of 0.025 ng/mL and a lower limit of quantification (LLOQ) of 0.05 ng/mL for both analytes. Linearity was observed at 0.05–10.0 ng/mL (rThe presented method is useful for human drug level monitoring of physostigmine and eseroline in accordance with current guidelines. Remarkably low plasma concentrations can be quantified after LLE with gradient elution and fluorescence detection, making this a suitable method for pharmacokinetic studies in a clinical setting.

Improved liquid-chromatographic method for determination of serum cortisol.

1979 ◽  
Vol 25 (7) ◽  
pp. 1293-1296 ◽  
Author(s):  
P M Kabra ◽  
L L Tsai ◽  
L J Marton
Keyword(s):  
Limit Of Detection ◽  
Internal Standard ◽  
Serum Cortisol ◽  
Peak Height ◽  
Reversed Phase ◽  
Column Temperature ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract We describe a specific and precise method for measuring concentrations of cortisol in serum or plasma by liquid chromatography. Cortisol, together with an internal standard, equilenin, is extracted from 1 mL of serum or plasma and analyzed isocratically on a reversed-phase column with a mobile phase of acetonitrile/phosphate buffer (30/70, by vol.), at a flow rate of 2.0 mL/min. The eluted cortisol is detected by its absorption at 254 nm and quantitated by peak height measurements. Each analysis requires no longer than 15 min at the optimum column temperature of 50 degrees C. The lower limit of detection for cortisol is about 2 ng/sample for a standard solution; sensitivity is routinely 5 micrograms/L of serum. Analytical recoveries exceeded 95%, with good day-to-day precision (coefficients of variation between 4 and 7%). Of more than 50 drugs and steroids tested for possible interference, only the steroids cortisone, prednisone, and prednisolone may interfere with the analysis of cortisol.

Liquid-chromatographic determination of vitamin K1 in plasma, with fluorometric detection.

1986 ◽  
Vol 32 (10) ◽  
pp. 1925-1929 ◽  
Author(s):  
Y Haroon ◽  
D S Bacon ◽  
J A Sadowski
Keyword(s):  
Limit Of Detection ◽  
Lipid Fraction ◽  
Internal Standard ◽  
Reversed Phase ◽  
Phase System ◽  
Fluorometric Detection ◽  
Vitamin K1 ◽  
Crude Lipid ◽  
Zinc Metal ◽  
Liquid Chromatographic

Abstract This assay for phylloquinone (vitamin K1) in plasma requires a single liquid-chromatographic step. Much smaller volumes of plasma (0.5-1.0 mL) are required than in previous assays. Before liquid chromatography, we purified crude lipid extracts by conventional chromatography on silica, then extracted the lipid fraction by dissolving it in an acidic mixture of hexane/acetonitrile (1/4 by vol) containing 70 mmol of zinc chloride per liter. The vitamin K1 was selectively extracted into acetonitrile after being converted to vitamin K1 hydroquinone by addition of zinc metal. This procedure removes greater than 99% of contaminating lipids. We injected the lipid extract directly onto a reversed-phase column after re-converting the vitamin K1 hydroquinone to vitamin K1. Vitamin K1 was quantified by comparison with the internal standard (dihydro-vitamin K1) and detected fluorometrically after post-column "on-line" reduction to the hydroquinone with zinc metal. The lower limit of detection for vitamin K1 in the final reversed-phase system was about 0.05 microgram/L plasma; CVs for replicates were less than 10%. The mean concentration of vitamin K1 in plasma from 22 healthy fasting adults was 0.55 (range 0.09-2.12) micrograms/L.

Liquid Chromatographic Determination of Residual Isocyanate Monomers in Plastics Intended for Food Contact Use

1995 ◽  
Vol 78 (3) ◽  
pp. 711-718 ◽  
Author(s):  
Andrew P Damant ◽  
Sue M Jickells ◽  
Laurence Castle
Keyword(s):  
Limit Of Detection ◽  
Internal Standard ◽  
Standard Addition ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Good Precision ◽  
Food Packages ◽  
Food Package ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed for the analysis of 10 isocyanates in polyurethane articles and laminates intended for food use. Residual isocyanates are extracted by dichloromethane with concurrent derivatization by 9-(methylaminomethyl)anthracene. The resultant derivatives are analyzed by reversed-phase LC with fluorescence detection. Separation of the isocyanates was studied and optimized. Quantitation uses 1-naphthyl isocyanate as internal standard and standard addition to the food package. Validation demonstrated the method to have good precision (± 2–5%) and recovery (83–95%) for samples spiked with isocyanates at 0.1 mg/kg. The limit of detection was 0.03 mg/kg. Analysis of 19 commercial polyurethane or laminate food packages demonstrated that the method was not prone to interferences. Residues of diphenylmethane-4,4′-diisocyanate were detected in 5 packages and ranged from 0.14 to 1.08 mg/kg.

Determination of levofloxacin by HPLC with fluorescence detection in human breast milk

Bioanalysis ◽  
2021 ◽  
Author(s):  
Sıdıka Ertürk Toker ◽  
Gamze Ergin Kızılçay ◽  
Olcay Sagirli
Keyword(s):  
Breast Milk ◽  
Fluorescence Detection ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Reversed Phase ◽  
Calibration Graph ◽  
Human Breast Milk ◽  
Human Breast ◽  
Limit Of Quantification

Aim: A new HPLC method with fluorescence detection has been developed and validated for the determination of levofloxacin, one of the fluoroquinolone class antibiotics, in breast milk. Materials & methods: Chromatographic separation was carried out on a reversed phase C18 column with acetonitrile and 10 mM o-phosphoric acid (25:75,v/v) mobile phase composition. Moxifloxacin was used as internal standard and the peaks were detected by fluorescence detection. Results & conclusion: Calibration graph was found linearly within the range of 2.5–500 ng/ml. Limit of detection and limit of quantification were found to be 0.63 and 2.11 ng/ml, respectively. Mean absolute recovery was 96.18%. The developed method has been successfully applied to the determination of levofloxacin in human breast milk taken from two healthy volunteers.

scholarly journals Nonextractive Procedure and Precolumn Derivatization with 7-Chloro-4-nitrobenzo-2-oxa-1,3-diazole for Trace Determination of Trimetazidine in Plasma by High-Performance Liquid Chromatography with Fluorescence Detection

2008 ◽  
Vol 91 (5) ◽  
pp. 1037-1044 ◽  
Author(s):  
Ibrahim A Darwish ◽  
Ashraf M Mahmoud ◽  
Nasr Y Khalil
Keyword(s):  
Human Plasma ◽  
Fluorescence Detection ◽  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Pharmacokinetic Studies ◽  
Precolumn Derivatization ◽  
Trace Determination ◽  
Relative Standard

Abstract A highly sensitive high-performance liquid chromatographic method with fluorescence detection has been developed and validated in a single laboratory for the trace determination of trimetazidine (TMZ) in human plasma. Fluoxetine (FLX) was used as the internal standard. TMZ and FLX were isolated from plasma by protein precipitation with acetonitrile and derivatized by heating with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole in pH 8 borate buffer at 70C for 30 min. Separations were performed in the isocratic mode on a Nucleosil CN column with the mobile phase acetonitrile10 mM sodium acetate buffer (pH 3.5)methanol (47 + 47 + 6, v/v/v) at a flow rate of 1.0 mL/min. The derivatized samples were excited at 470 nm and monitored at an emission wavelength of 530 nm. Under the optimum chromatographic conditions, a linear relationship with a good correlation coefficient (r 0.9997, n 5) was obtained for the peak area ratio of TMZ to FLX and for TMZ concentrations of 1120 ng/mL. The proposed method has the lowest limits of detection and quantitation reported to date for the determination of TMZ in plasma with values of 0.3 and 0.95 ng/mL, respectively. The values for intra- and interassay precision were satisfactory; the relative standard deviations were 4.04. The accuracy of the method was demonstrated; the recoveries of TMZ from spiked human plasma were 98.13102.83 0.24.04. The method has high throughput because of its simple sample preparation procedure and short run time (<10 min). The results demonstrated that the proposed method would have great value when applied in pharmacokinetic studies for TMZ.

Simultaneous liquid-chromatographic determination of 12 common sedatives and hypnotics in serum.

1978 ◽  
Vol 24 (4) ◽  
pp. 657-662 ◽  
Author(s):  
P M Kabra ◽  
H Y Koo ◽  
L J Marton
Keyword(s):  
Serum Proteins ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Acetonitrile Solution ◽  
Column Temperature ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We present a method for simultaneously determining 12 hypnotics and sedatives (primidone, methyprylon, phenobarbital, butabarbital, butalbital, ethchlorvynol, pentobarbital, amobarbital, phenytoin, glutethimide, secobarbital and methaqualone) in 200 microliter of serum. Serum proteins are precipitated with an acetonitrile solution containing 5-(4-methylphenyl)-5-phenylhydantoin, the internal standard. The drugs are eluted from a reversed-phase column with a mobile phase consisting of an acetonitrile/phosphate buffer, at a flow rate of 3.0 ml/min. The eluted drugs are detected by their absorption at 195 nm; their quantities are estimated from their peak heights. Each analysis requires no longer than 30 min at the optimum column temperature of 50 degrees C. The lower limit of detection for all of these drugs is less than 10 ng/sample for drug standard. A sensitivity of 1.0 mg/liter of serum is attained routinely for each of the drugs. Analytical recoveries for the 12 drugs varied from 94 to 112%, with good day-to-day precision (CV between 3.8 and 10.4%). Of more than 35 drugs tested for possible interference, only ethotoin interferes with the analysis of phenobarbital.

Determination of clozapine, norclozapine, and clozapine-N-oxide in serum by liquid chromatography

1993 ◽  
Vol 39 (8) ◽  
pp. 1656-1659 ◽  
Author(s):  
S A Volpicelli ◽  
F Centorrino ◽  
P R Puopolo ◽  
J Kando ◽  
F R Frankenburg ◽  
...  
Keyword(s):  
Internal Standard ◽  
Reversed Phase ◽  
Therapeutic Monitoring ◽  
Pharmacokinetic Studies ◽  
Photodiode Array Detection ◽  
Photodiode Array ◽  
Array Detection ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract We report a new assay to measure the serum concentrations of the atypical antipsychotic drug clozapine and two major metabolites, norclozapine and clozapine-N-oxide. The analytes and an internal standard (triprolidine) were extracted from alkalinized samples into ethyl acetate and back-extracted into 0.1 mol/L HCl. The acid extracts were chromatographed on a reversed-phase liquid chromatographic column with photodiode array detection (210-340 nm). With the 254-nm signal, between-run imprecision (CV) was < 2% for clozapine and norclozapine at 400 micrograms/L, and 4.1% for clozapine-N-oxide at 100 micrograms/L. Absolute recovery exceeded 65%, and the detection limit was approximately 3-4 micrograms/L. In 25 patients at steady state at a mean daily clozapine dosage of 269 mg (3.09 mg/kg), clozapine averaged 231 +/- 144 micrograms/L (mean +/- SD); norclozapine and clozapine-N-oxide concentrations averaged 84% and 23% that of clozapine. Analyte concentrations were significantly correlated with daily dose. The method's ability to quantify clozapine and two major metabolites simultaneously with precision and sensitivity makes it useful in pharmacokinetic studies and therapeutic monitoring.

scholarly journals Improved Method for Determination of Abamectin and Ivermectin in Cattle Plasma

2001 ◽  
Vol 84 (6) ◽  
pp. 1730-1734
Author(s):  
Guang Zhi Wei ◽  
Jun Suo Li
Keyword(s):  
Fluorescence Detection ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Trifluoroacetic Anhydride ◽  
Improved Method ◽  
Alumina Column ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic ◽  
Fluorescent Derivative

Abstract A liquid chromatographic (LC) method was developed for determination of abamectin (ABM) and ivermectin (IVM) in cattle plasma. The sample was extracted with acetonitrile and cleaned up on an alumina column. After conversion to stable fluorescent derivative with trifluoroacetic anhydride and N-methylimidazole, the sample was analyzed by LC with fluorescence detection (Ex 365 nm and Em 475 nm). Doramectin was used as an internal standard. Recoveries ranged from 91.2 to 100.7% for IVM and from 87.0 to 98.7% for ABM, with 1–50 ng/mL fortified samples. The coefficients of variation were <10.1%. The limit of detection was 0.02 ng/mL for ABM and IVM in 1.0 mL samples.

Liquid-chromatographic determination of alpha- and gamma-tocopherols in erythrocytes, with fluorescence detection.

1983 ◽  
Vol 29 (10) ◽  
pp. 1840-1842 ◽  
Author(s):  
J Lehmann ◽  
H L Martin
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract We have adapted to erythrocytes a method for the determination of alpha- and gamma-tocopherols in plasma and platelets. Erythrocytes (50 microL) were extracted with methanol containing tocol (internal standard) and pyrogallol. Tocopherols were partitioned into chloroform, washed, and injected in methanol onto a reversed-phase (C18) "high-performance" liquid-chromatographic column. The mobile phase was methanol/water (99/1 by vol) at a flow rate of 2 mL/min and detection was with a "high-performance" spectrophotofluorometer. The limit of detection for either tocopherol is 0.10 microgram/mL of packed cells. Analytical recoveries ranged from 93 to 104%. Some values for tocopherols in human erythrocytes are presented.

Sign in / Sign up

Export Citation Format

Share Document