Rapid HPTLC Analysis of Oxcarbazepine in Human Plasma

JPC – Journal of Planar Chromatography – Modern TLC - A sensitive high-performance thin-layer chromatographic method has been developed for analysis of oxcarbazepine (OXC) in human...     

Rapid and Sensitive LC Method for the Analysis of Gemifloxacin in Human Plasma

A simple liquid chromatographic method for the determination of gemifloxacin (CAS number 175463-14-6) in human plasma has been developed. An aliquot quantity of 1 mL plasma sample was taken and 0.1 mL internal standard was added and mixed. 1 mL methanol was added to it. The mixture was then sonicated for 10 min followed by 20 min centrifugation at 5000 rpm (g = 3600). The supernatant layer was separated and filtered through simple filtration unit (membrane filter, 0.45 μm) and injected into the LC system consisting of Hypersil BDS, C18 (250 × 4.6 mm, 5 μm particle size) column, using 1% formic acid : methanol = 65:35 (v/v) as mobile phase with ultra violet detection at 328 nm. Lower limit of detection was 20 ng mL^?1 and lower limit of quantitation was 50 ng mL^?1. Maximum between-run precision was 14.614%. Mean extraction recovery was found to be 87.32 to 89.32%. Stability study showed that after three freeze-thaw cycles the loss of three quality control samples were less than 10%. Samples were stable at room temperature for 12 h and at ?20 °C for 3 months. Before injecting into LC system, the processed samples were stable for at least 8 h. The method was used to perform bioequivalence study in human volunteers.     

LC–ESI–MS for Rapid and Sensitive Determination of Aripiprazole in Human Plasma

A rapid, sensitive, and accurate high-performance liquid-chromatographic–mass spectrometric (HPLC–MS) method, with estazolam as internal standard, has been developed and validated for determination of aripiprazole in human plasma. After liquid–liquid extraction the compound was analyzed by HPLC on a C₁₈ column, with acetonitrile—30 mm ammonium acetate containing 0.1% formic acid, 58:42 (v/v), as mobile phase, coupled with electrospray ionization mass spectrometry (ESI-MS). The protonated analyte was quantified by selected-ion recording (SIR) with a quadrupole mass spectrometer in positive-ion mode. Calibration plots were linear over the concentration range 19.9–1119.6 ng mL⁻¹. Intra-day and inter-day precision (CV%) and accuracy (RE%) for quality-control samples (37.3, 124.4, and 622.0 ng mL⁻¹) ranged between 2.5 and 9.0% and between 1.3 and 3.5%, respectively. Extraction recovery of aripiprazole from plasma was in the range 75.8–84.1%. The method enables rapid, sensitive, precise, and accurate measurement of the concentration of aripiprazole in human plasma.     

A Sensitive Gas Chromatographic Method for the Determination of Metoprolol in Human Plasma

Abstract

A sensitive method for the determination of metoprolol in plasma has been developed. The procedure is based on gas chromatographic measurements of derivatized metoprolol, using 9-bromophenanthrene as internal standard. Metoprolol is derivatized with pentafluoropropionic anhydride. The resulting derivative gives a four-fold increase in sensitivity compared to the published methods where trifluoroacetic anhydride was used for derivatization.     

Rapid and Sensitive Determination of Furosemide in Human Plasma by High Pressure Liquid Chromatography

Abstract

A rapid and sensitive determination of furosemide in human plasma by high pressure liquid chromatography is described. The drug is extracted from plasma after addition of the internal standard (2,4-dinitrophenol), the extract is concentrated by means of evaporation and injected on to the liquid chromatograph. Separation is achieved on a reversed-phase column with 50 % methanol in water, containing 0.5 % glacial acetic acid; detection is carried out at 340 nm. The method is linear up to 5 μml and can determine concentrations down to 0.1 μg/ml in a 1ml plasma sample. It is much faster than existing methods and is at least as good with respect to accuracy and sensitivity.     

Sensitive LC–ESI–MS Method for Determination of Tiopronin in Human Plasma

A sensitive liquid chromatographic–electrospray ionization–mass spectrometric (LC–MS) method has been developed for direct measurement of the concentration of tiopronin in human plasma. Hydrochloric acid solution was used to stabilize the tiopronin and prevent formation of a dimer, or reaction with endogenous thiols. The method involved liquid–liquid extraction of tiopronin from plasma samples with ethyl acetate, simple reversed-phase chromatography, and mass spectrometric detection with nanogram detection limits. Acetaminophen was used as internal standard (IS). The limit of quantification was 5 ng mL^?1 (RSD 4.3%). The method was validated within the linear range 5–500 ng mL^?1. The correlation coefficient for the calibration regression line was 0.9997 or better. Intra-day and inter-day accuracy were better than 15%. The method has been successfully used for a pharmacokinetic study with human subjects. Among the pharmacokinetic data obtained, t _1/2 was 2.37 ± 0.63 h and T _max was 4 h.     

Application of a Sensitive, Rapid and Validated LC–MS–MS Method for the Determination of Carvedilol in Human Plasma

Carvedilol was quantified in human plasma after a single 25 mg oral dose of the drug was given to 26 healthy volunteers. An applied Biosystems Sciex API 3200 triple quadrupole mass spectrometer in multiple reaction monitoring mode, using electrospray ionization in the positive ion mode was used. Simple solid phase extraction was followed by C₁₈ reverse phase chromatography and tandem mass spectrometric detection using propranalol as the internal standard. The mean recovery for carvedilol was 91.2% with a lower limit of quantification of 0.5 ng mL^?1. This validated assay method makes use of the increased sensitivity and selectivity of tandem mass spectrometry detection to allow for a more rapid and selective method for the determination of carvedilol in human plasma.     

A Rapid and Sensitive Method for The Determination of Diclofenac Sodium in Plasma By High-Performance Liquid Chromatography

Abstract

A rapid and sensitive high-performance liquid chromatographic method for the determination of diclofenac sodium in plasma has been developed. The method is specific and free of interference from metabolites and common anti-inflammatory agents. The UV detector (215 nm) response was linear over a range of 5-1000 ng/ml. Day-to-day and within-day calibration curves were reproducible. The method was validated by analysis of spiked human plasma samples, partly in a blind fashion. The accuracy and precision of the method are satisfactory over the range of 5-1000 ng/ml. The method was cross-checked with the GC method. Results show a correlation coefficient of 0.983 and a slope of 1.04. The method is suitable for the routine analysis of large numbers of plasma samples usually obtained in bioavailability and pharmacokinetic studies.     

HPTLC Determination of Atorvastatin in Plasma

High performance liquid chromatography has been the most popular choice for the determination of atorvastatin. In this study, two-step isocratic chromatography on silica gel 60F254 HPTLC layer and densitometric quantitation at λ = 280 nm was developed for the separation of atorvastatin from plasma constituencies and sodium diclofenac as peak-tracer. The established HPTLC method was validated in terms of LOD/LOQ, linearity, recovery and repeatability. The calibration function of the analyte was linear in the range 101–353.5 ng zone^?1 and the correlation coefficient was 0.9969. The limits of detection and quantitation were 30.3 and 101 ng zone^?1. The recovery and relative standard deviation obtained from between-days analysis were 97.5–103.0 and 1.7–3.4%.     

Rapid Determination of Pentazocine in Human Plasma and Urine by a Potentiometric Method

Abstract

A fast potentiometric determination method has been reported for pentazocine in human plasma without complicated pretreatments using a coated-wire potentiometric selective electrode. The sensing membrane was made by incorporating of ion-association complexes of pentazocine cation and sodium tetraphenyl borate (NaTPB) in a polyvinyl chloride. The sensor exhibited fast, stable, and linear Nernstian response over the range of 5 × 10^?5 to 0.1 mol L^?1 pentazocine with a slope of 57.8 mV per decade and with detection limit of 3.2 × 10^?5 mol L^?1. The proposed sensor has been used for determination of pentazocine in human plasma and urine.     

Sensitive, Selective, Precise and Accurate LC–MS Method for Determination of Clonidine in Human Plasma

A selective and sensitive liquid chromatography–mass spectrometric method in ESI (+ve) mode was developed and validated completely in human plasma. Clonidine and IS, carbamazapine, were extracted from human plasma via liquid–liquid extraction with ethyl acetate. Following evaporation under nitrogen, the residue was reconstituted with mobile phase and analyzed using API 4000 LC–MS–MS system. An isocratic program with binary mobile phases (0.1% formic acid in water and acetonitrile) was used to separate interference peaks by a C18 analytical column. Linearity range was 0.49–73.98 ng mL^?1. The intra- and inter-day accuracy and precision were within acceptable limits (≤15%). This method was successfully applied to a single dose 25 μg tablets BE study of clonidine in healthy male volunteers.     

Sensitive,Selective, Precise and Accurate LC–MS Method for Determination of Clonidine in Human Plasma

A selective and sensitive liquid chromatography–mass spectrometric method in ESI (+ve) mode was developed and validated completely in human plasma. Clonidine and IS, carbamazapine, were extracted from human plasma via liquid–liquid extraction with ethyl acetate. Following evaporation under nitrogen, the residue was reconstituted with mobile phase and analyzed using API 4000 LC–MS–MS system. An isocratic program with binary mobile phases (0.1% formic acid in water and acetonitrile) was used to separate interference peaks by a C18 analytical column. Linearity range was 0.49–73.98 ng mL⁻¹. The intra- and inter-day accuracy and precision were within acceptable limits (≤15%). This method was successfully applied to a single dose 25 μg tablets BE study of clonidine in healthy male volunteers.

     

Highly Sensitive LC Method with Automated Co-Sense System and Fluorescence Detection for Determination of Sertraline in Human Plasma

A highly sensitive LC method with column-switching “Co-sense” system and fluorescence detection has been proposed for trace determination of sertraline in human plasma. A simple pre-column derivatization procedure with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole reagent was employed. Fluxetine was used as an internal standard. Under the optimum chromatographic conditions, a linear relationship with good correlation coefficient (r = 0.9997) was found between the peak area ratio and sertraline concentration in the range of 5–5,000 ng mL^?1. The limit of detection and limit of quantitation were 1.41 and 4.28 ng mL^?1, respectively. The intra- and inter-assay precisions were satisfactory; the relative standard deviations did not exceed 5.63%. The accuracy of the method was proved; the recovery of sertraline from the spiked human plasma was 99.76–102.62 ± 2.19–5.63%. The proposed method had high throughput as the analysis involved simple sample pre-treatment procedure and short run-time (~12 min). The results demonstrated that the method would have a great value if applied in bioavailability and pharmacokinetic studies for sertraline.     

Development and Validation of a Densitometric HPTLC Method for Quantitative Analysis of Levofloxacin in Human Plasma

JPC – Journal of Planar Chromatography – Modern TLC -     

New Rapid Validated HPTLC Method for the Determination of Lycorine in Amaryllidaceae Plants Extracts

A rapid, accurate, specific, repeatable and robust HPTLC method for the determination of lycorine in different Amaryllidaceae plant extracts is presented in this work. No article related to the HPTLC determination of lycorine in plant extracts has been reported in literature. Lycorine, a common alkaloid of family Amaryllidaceae, moreover, there have been some recent reports which reveal the interaction of lycorine with DNA and tRNA. It has, therefore, been to the interest of phytochemists to determine the content of this alkaloid in Amaryllidaceaous plants.     

Rapid and Sensitive Liquid Chromatography-Tandem Mass Spectrometry for Quantification of Glycyrrhetic Acid in Human Plasma

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry(LC-MS/MS) for the determination of glycyrrhetic acid in human plasma with ginsenoside Rh2 as internal standard was developed and validated. The plasma samples were prepared via liquid-liquid extraction with ethyl acetate. Chromatographic separation was accomplished on a Venusil MP-C18(50 mm×2.1 mm, 5 μm i.d.) column at 25 °C. The mobile phase consisted of acetonitrile/5 mmol?L-1 ammonium acetate(10:90, volume ratio) at a flow rate ...     

A Simple and Sensitive LC Method for Quantification of Cefteram in Human Plasma

A simple and sensitive liquid chromatographic method was developed for quantification of cefteram in human plasma. Amoxicillin was used as an internal standard. The present method used protein precipitation for extraction of cefteram from human plasma. Separation was carried out on a reversed-phase C₁₈ column. The column effluent was monitored by UV detection at 262 nm. The mobile phase was a mixture of methanol and water containing 0.3% v/v triethylamine and 0.6% v/v glacial acetic acid (35:65:0.3:0.6 v/v) at a flow rate of 0.30 mL min^?1. The column temperature was 20 °C. This method was linear over the range of 47.5–4,750.0 ng mL^?1 with determination coefficient greater than 0.99. The mean extraction recovery of cefteram and IS was ≥76.82 and ≥76.49%, respectively, and the method was found to be precise, accurate, and specific during the study. The method was successfully applied for a pharmacokinetic study of cefteram in human.     

A Rapid HPLC Method for Determination of Imipenem in Plasma

Abstract

A high performance liquid chromatographic method was developed for the determination of imipenem concentrations in plasma. This method involves stabilization of plasma with a mixture of 2-(N-morpholine)-ethanesulf onic acid and ethylene glycol (1:1). Samples are ultrafiltered using a membrane separation system and the ultrafiltrate injected directly onto a octyldecyl column. Chromatography is performed in the reverse-phase mode with a mobile phase of acetonitrile-phosphate buffer-triethylamine (pH 7.0). The lower limit of sensitivity was 1mcg/ml using UV detection at 300nm. Recovery and reproducibility results, and interferences from other therapeutic agents are presented and discussed. The assay procedure is applied to estimate pharmacokinetic parameters of imipenem in a thermally injured patient.     

A Rapid Liquid Chromatographic Method for Determination of Flecainide in Human Blood Plasma Using Ultraviolet Detection

Abstract

A liquid chromatographic method for the assay of the antiarrhythmic drug flecainide in plasma has been developed. The method is rapid, simple and with sufficient detection sensitivity to render it suitable for therapeutic drug monitoring. Flecainide and added internal standard, a non-fluorinated analogue, were extracted by a single ether extraction from alkalinized plasma followed by a back-extraction of the ether with dilute phosphoric acid. A portion of the acid extract was then applied directly to a 30 cm ODS column eluting isocratically with 30% acetonitrile in water containing 0.01M dibutylamine phosphate. Monitoring was by ultraviolet detection at 214 nm and the total run time was 8 min. This method is specific and can quantitate plasma levels to less than 30 ng/ml (free base) from 0.5 ml of plasma without interference from antiarrhythmic drugs commonly used in therapy.     

A Sensitive Flow Injection Fluorimetry for the Determination of Carbamazepine in Human Plasma

Abstract

A simple, sensitive, and specific flow injection fluorimetric method has been developed for the determination of carbamazepine (CBZ). The proposed method is based on use of a solid‐phase reactor containing lead dioxide for on‐line oxidization of CBZ into a strongly fluorescent compound in a medium of phosphoric acid. The product has a green‐yellow fluorescence at a maximum excitation wavelength of 355 nm and an emission wavelength of 478 nm. Under the optimum conditions, the fluorescence intensity is proportional to the concentration of CBZ ranging from 0.0005 to 4.000 µg mL^?1. The detection limit is 5.7×10^?5 µg mL^?1 (2.4×10^?10 mol L^?1) and the relative standard deviation is 1.4% at the sampling rate of 45 h^?1. The proposed method has been applied to clinical estimation of CBZ in real patients' plasma samples with the results compared with those obtained by HPLC method.