High-Performance Liquid Chromatographic Determination of Cefepime and Cefazolin in Human Plasma and Dialysate

A simple high-performance liquid chromatographic (HPLC) method was developed for the simultaneous determination of cefepime and cefazolin in human plasma and dialysate. For component separation, the method utilized a C₁₈ column with an aqueous mobile phase of dibasic potassium hydrogen phosphate (pH 7.0) and methanol gradient at a flow rate of 1 mL min⁻¹. The method demonstrated linearity from 2.0 to 100.0 μg mL⁻¹ (r > 0.999) with detection limit of 1 μg mL⁻¹ for both cefepime and cefazolin. The method was utilized for evaluation of plasma and dialysate samples in a clinical study evaluating the dialyzer clearance of cefepime and cefazolin using high-flux hemodialysis with varying blood flow rates in chronic kidney failure patients undergoing hemodialysis and peritoneal dialysis treatment.     

HPLC Determination of DCJW in Rat Plasma and Its Application to Pharmacokinetics Studies

A high-performance liquid chromatography–UV method for determining DCJW concentration in rat plasma was developed. The method described was applied to a pharmacokinetics study of intramuscular injection in rats. The plasma samples were deproteinized with acetonitrile in a one-step extraction. The HPLC assay was carried out using a VP-ODS column and the mobile phase consisting of acetonitrile–water (80:20, v/v) was used at a flow rate of 1.0 mL min⁻¹ for the effective eluting DCJW. The detection of the analyte peak area was achieved by setting a UV detector at 314 nm with no interfering plasma peak. The method was fully validated with the following validation parameters: linearity range 0.06–10 μg mL⁻¹ (r > 0.999); absolute recoveries of DCJW were 97.44–103.46% from rat plasma; limit of quantification, 0.06 μg mL⁻¹ and limit of detection, 0.02 μg mL⁻¹. The method was further used to determine the concentration–time profiles of DCJW in the rat plasma following intramuscular injection of DCJW solution at a dose of 1.2 mg kg⁻¹. Maximum plasma concentration (C _max) and area under the plasma concentration–time curve (AUC) for DCJW were 140.20 ng mL⁻¹ and 2405.28 ng h mL⁻¹.     

High-Performance Liquid Chromatographic Determination of Cinnarizine in Workplace Air

Summary Cinnarizine is a pharmaceutical drug used in the treatment of cerebral and peripheral vascular diseases. A reversed-phase liquid chromatographic method with fluorescence detection has been developed for determination of the drug in workplace air. Air sampling in the workplace is performed on perchlorovinyl filters (FPP), the filters are extracted with methanol for 40 min, and the extract (50 L) is injected and separated on a 250 mm × 4.6 mm i.d., 5 m particle, C₈ reversed-phase column with 1% ammonium acetate (pH 4.5)–acetonitrile, 1:4 (v/v), as mobile phase at a flow rate of 1 mL min^–1.     

Development and Validation of a Liquid Chromatographic Method for Determination of Efavirenz in Human Plasma

A simple, rapid, and sensitive high-performance liquid chromatographic method for estimation of efavirenz in human plasma has been developed and validated. Chromatography was performed with C₁₈ analytical column and 50:50 acetonitrile–phosphate buffer (pH 3.5) as mobile phase. Compounds were monitored by UV detection at 247 nm. The retention time for efavirenz was 6.45 min and that for the internal standard, nelfinavir, was 2.042 min. Response was a linear over the concentration range of 0.1 μg–10 μg mL⁻¹ in human plasma. The method was simple, specific, precise and accurate and was useful for bioequivalence and pharmacokinetic studies of efavirenz.     

Validation of a Novel HPLC Method for the Determination of Raloxifene and Its Pharmacokinetics in Rat Plasma

A novel HPLC method has been developed and validated for the determination of Raloxifene in rat plasma. Samples were prepared based on a simple protein precipitation. Separation of Raloxifene in plasma was performed on a C18 column, with a mobile phase of acetonitrile–ammonium acetate. Good linearity was demonstrated in the range of 0.2–75.0 μg mL⁻¹ (r = 0.9931). The method was used to measure the concentration and pharmacokinetics of Raloxifene in rat plasma after a single oral dose, and a linear pharmacokinetic profile of Raloxifene was found.     

Simple High-Performance Liquid Chromatographic Assay, with Post-Column Derivatization, for Simultaneous Determination of Mycophenolic Acid and its Glucuronide Metabolite in Human Plasma and Urine

Two simple high-performance liquid chromatographic (HPLC) methods have been established for simultaneous determination of mycophenolic acid (MPA) and its glucuronide metabolite (MPAG) in human urine, and of their total and unbound forms in human plasma. For total MPA and MPAG analysis sample preparation entailed precipitation of protein with acetonitrile and isolation of the free analytes from the plasma by ultrafiltration. For urine samples, fivefold dilution with water was used. MPAG was determined by UV detection whereas MPA was quantified by fluorescence detection after post-column derivatization with 0.2 M sodium hydroxide solution. For plasma, response was found to be linearly dependent on concentration over the ranges 0.1–40 μg mL^-1 and 0.01–1 μg mL^-1 for total and free MPA, respectively, and 10–200 μg mL^-1 and 2.5–100 μg mL^-1 for total and free MPAG, respectively. For urine, linearity was observed from 0.1 to 50 μg mL^-1 for MPA and 10 to 500 μg mL^-1 MPAG in the urine before dilution. The methods reported were found to be accurate and reproducible for quantifying the level of MPA and MPAG and can thus be used for clinical pharmacokinetic studies and for therapeutic drug monitoring. Contributed equally to this work An erratum to this article is available at .     

Simple Liquid Chromatographic Determination of Minocycline in Brain and Plasma

A new high-performance liquid chromatography assay was developed for the determination of minocycline in plasma and brain. A solid–liquid extraction procedure was coupled with a reversed-phase HPLC system. The system requires a mobile phase consisting of acetonitrile:water:perchloric acid (26:74:0.25, v/v/v) adjusted to pH 2.5 with 5 M sodium hydroxide for elution through a RP8 column (250 × 3.0 mm, i.d.) with UV detection set at 350 nm. The method proved to be accurate, precise (RSD < 20%) and linear between 0.15–20 μg mL⁻¹ in plasma and 1–20 μg mg⁻¹ in brain. The method was successfully applied to a blood-brain barrier minocycline transport study.     

Liquid Chromatographic Determination of Sulfamonomethoxine, Sulfadimethoxine, and their N 4-Acetyl Metabolites in Chicken Plasma

An environmentally-friendly method has been established for simultaneous determination of sulfamonomethoxine, sulfadimethoxine, and their N⁴-acetyl metabolites in chicken plasma. The sample is prepared by mixing with 4 mol L^–1 ammonium sulfate solution then centrifugation, and analysis is performed by high-performance liquid chromatography (HPLC) on a polyethylene glycol reversed-phase column with 0.001 mol L^–1 sodium acetate solution as mobile phase and photodiode-array detection. Average recoveries from samples spiked with 0.1, 0.5, and 1.0 g mL^–1 of each drug were >78% and relative standard deviations were within 4%. The practical quantitation limits were 0.09 g mL^–1. No organic solvents or hazardous reagents were used at any stage of the analysis.     

High-Performance Liquid Chromatographic Method for Determination and Pharmacokinetic Study of Chlorogenic Acid in the Plasma of Rats After Administration of the Chinese Medicinal Preparation Luying Decoction

A simple and sensitive high-performance liquid chromatographic method has been developed for determination of chlorogenic acid in rat plasma. Chlorogenic acid was extracted from plasma samples with methanol. HPLC analysis of the extracts was performed on a C₁₈ column (250 mm × 4.6 mm i.d., 5 µm particles). The mobile phase was acetonitrile −1% formic acid (9:91, v/v). The calibration plot was linear over the range 0.0420–2.10 µg mL⁻¹ and the lower limit of quantification was 0.0420 µg mL⁻¹. The method was reproducible and reliable with intra-day precision better than 8.2%, inter-day precision better than 9.1%, accuracy within ±8.3%, and mean extraction recovery above 84.4%. The validated method was successfully applied to pharmacokinetic studies of chlorogenic acid in rat plasma after administration of Luying decoction.     

反相高效液相色谱法测定人血浆中异丙酚浓度

用柱前衍生化反相高效液相色谱法测定人血浆中异丙酚浓度,为临床药理学研究提供了依据。提取的异丙酚及内标麝香草酚同时以Ｇｉｂｂｓ试剂衍生化,衍生物经色谱柱分离和紫外检测,异丙酚在５０～１５００μｇ／Ｌ浓度范围内呈线性关系（ｒ＝０．９９９１）。方法平均变异系数为６．１％,最低检出浓度为２４．８μｇ／Ｌ,已满意地用于临床药理学研究。     

Rapid Liquid Chromatographic – Tandem Mass Spectrometric Method for the Quantification of Pentoxifylline in Human Plasma

A simple, rapid, sensitive and selective liquid chromatography / tandem mass spectrometry method was developed and validated for the quantification of pentoxifylline, a haemorheological agent. The analyte and internal standard, tamsulosin were extracted by liquid-liquid extraction with ethyl acetate and were separated using an isocratic mobile phase on a reverse phase C₁₈ column. The analytes were analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective [M+H]⁺ ions, m/z 279/138 for pentoxifylline and m/z 409/228 for the IS. The assay exhibited a linear dynamic range of 2–1000 ng mL⁻¹ for pentoxifylline in human plasma. The lower limit of quantification was 2 ng mL⁻¹ with a relative standard deviation of less than 10%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 1.5 min for each sample made it possible to analyze more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. Revised: 4 and 20 October 2005     

Supported Liquid Membrane Work-Up of Blood Plasma Samples Coupled On-Line to Liquid Chromatographic Determination of Basic Antidepressant Drugs

An automated sample pretreatment of human blood plasma for liquid chromatographic determination of three antidepressant drugs, dibenzepine; a tricyclic antidepressant (TCA), reboxetine; a selective noradrenaline reuptake inhibitor (SNRI) and fluvoxamine; a selective serotonin reuptake inhibitor (SSRI), based on supported liquid membrane (SLM) for unsurpassed sample clean-up and analyte enrichment, has been developed. The chromatograms after enrichment of plasma blank and aqueous blank are virtually indistinguishable. The entire analytical procedure revealed good linearity and low detection limits of 5, 15 and 20 ng mL^–1 for dibenzepine, reboxetine and fluvoxamine, respectively. No carry-over effects were noted. The repeatability of extraction at three concentrations in the range 40–150 ng mL^–1 for the three drugs was between ca. 3% and 7% as relative standard deviation. The reproducibility relative standard deviation during three different days (replacing the membrane each day) was not significantly higher.     

High-Performance Liquid Chromatographic Analysis of Amino Acids in Edible Seaweeds after Derivatization with Phenyl Isothiocyanate

Summary A reversed-phase high-performance liquid-chromatographic method has been used for analysis of the amino acids in edible seaweed. Sample proteins were hydrolysed with hydrochloric acid and the amino acids produced were derivatized with phenyl isothiocyanate. The resulting phenylthiocarbamyl amino acids were chromatographed on an ODS2 column with UV detection at 254 nm. The mobile phase was a mixture of 0.14 M ammonium acetate buffer, pH 6.4, containing 0.05% triethylamine (A) and 60:40 (v/v) acetonitrile–water (B), at a flow rate of 1.1 mL min^–1; the elution gradient (min:A%) was: 0:90, 8:90, 10:70, 12:70, 18:52, 20:0, 25:0, 28:90, 35:90. Method precision for the different amino acids was between 1.33 and 3.88% (relative standard deviation); detection limits were between 6.9 and 14.3 ng mL^–1. The amino acid content of the algae analysed ranged from 22.4 ± 1.9 to 138.0 ± 5.6 mg g^–1 d.w. The amino acids present at highest concentrations were glutamic acid, alanine, and phenylalanine.     

Simplified Solid-Phase Extraction Procedure and Liquid Chromatographic Determination of Celecoxib in Rat Serum

A simplified solid phase extraction method, eliminating a preliminary protein precipitation has been developed for the determination of celecoxib in rat plasma. The technique included a solid phase extraction of the serum samples on a [poly (divinylbenzene-co-N-vinylpyrrolidone)] sorbent. After conditioning, the cartridge was loaded with 0.5 mL of acidified serum containing internal standard. Elution was made with 1 mL of a mixture of acetonitrile and methanol (1/1, v/v). After evaporation of the eluate to dryness and reconstitution with methanol, the samples were analyzed on an octadecyl bonded phase with several mobile phases containing acetonitrile and a phosphate buffer. Detection was carried out using a Photodiode Array Detector. Full validation of the proposed method was provided (linearity range: 0.01–2 mg. L^–1, average extraction efficiency: 92.4%; average intra-day variability: 4.6% with an accuracy of 94.8%; average interday variability: 5% with an accuracy of 95.3%, limit of detection: 0.005 mg. L^–1, limit of quantification: 0.002 mg. L^–1). The proposed method was successfully utilised to quantify celecoxib in rat plasma for a pharmacokinetic study.Revised: 26 January and 23 April 2004     

High-Performance Liquid Chromatographic Assay of Zonisamide (1,2-benzisoxazole-3-methanesulfonamide) in Human Plasma using a Solid-Phase Extraction Technique

A selective and sensitive liquid chromatographic method was developed for the determination of zonisamide in small volumes of plasma. Zonisamide and the internal standard methyl 4-hydroxybenzoate were extracted from 0.2 mL of plasma with solid-phase extraction columns and eluted with methanol. Analysis of the extracts was performed on a Symmetry C₁₈ column with ultra-violet spectrophotometric detection. The calibration curve was linear over the concentration range of 0.05–5 g mL^–1 in plasma. Recoveries were reasonable for routine analyses; the limit of quantification was 0.05 g mL^–1 with a signal-to-noise ratio of 5. This method could be useful for the pharmacokinetic study of zonisamide in a limited volume of human plasma and for therapeutic drug monitoring.     

HPLC Analysis and Pharmacokinetics of Picroside I in Dog Plasma

A sensitive and selective HPLC–UV method established for determination of picroside I in dog plasma has been used to study the pharmacokinetics of the drug after intravenous administration of three different doses. Sample pretreatment consists in deproteination by addition of acetonitrile; l-ascorbic acid was used to improve the stability of picroside I. The lower limit of quantification of picroside I was 0.05 μg mL⁻¹. The recovery of the method was up to 90%. After intravenous administration to dogs picroside I was mainly distributed in the central compartment and was rapidly eliminated from the plasma; the mean elimination half-life was 30.54 ± 4.34, 30.20 ± 3.78, and 34.02 ± 1.88 min for doses of 2.5, 5, and 15 mg kg⁻¹, respectively, and the respective values of AUC _0–∞ were 81.04 ± 19.95, 198.50 ± 27.77, and 586.44 ± 103.08 μg min mL⁻¹. The different doses had no significant effect on the main pharmacokinetic data and the kinetics seemed to be linear in dosage range 2.5–15 mg kg⁻¹.     

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.     

RP-HPLC Determination of Linarin in Beagle Dog Plasma After Administration of Yejuhua Injection

A sensitive, simple, and accurate reversed-phase column liquid chromatographic (RP-LC) method with daidzein as an internal standard and UV detection at 348 nm has been developed for determination of linarin in beagle dog plasma. Plasma protein was precipitated by addition of acetonitrile and the remaining solution was evaporated to dryness. The resulting residue was then reconstituted in methanol and injected on to a 250 mm × 4.6 mm i.d., 5 μm particle, ODS analytical column. The mobile phase was a gradient prepared from acetonitrile and an aqueous solution (0.4%) of phosphoric acid; the flow rate was 1.0 mL min⁻¹. Response was a linear function of concentration over the range 3.4–1,373.3 ng mL⁻¹; the correlation coefficient (R ²) was 0.993. Mean recovery was 74.2%. Within-day and between-day precision were better than 8.8% relative standard deviation (RSD). The limit of quantification was 3.4 ng mL⁻¹. This RP-LC method was used successfully in pharmacokinetic studies of linarin in beagle plasma after administration of Yejuhua injection.     

Simultaneous Determination of Pioglitazone and Glimepiride by High-Performance Liquid Chromatography

A rapid and accurate HPLC method has been developed for simultaneous determination of pioglitazone and glimepiride. Chromatographic separation of the two pharmaceuticals was performed on a Cosmosil C₁₈ column (150 mm × 4.6 mm, 5 m) with a 45:35:20 (v/v) mixture of 0.01 m triammonium citrate (pH adjusted to 6.95 with orthophosphoric acid), acetonitrile, and methanol as mobile phase, at a flow rate of 1.0 mL min^–1, and detection at 228 nm. Separation was complete in less than 10 min. The method was validated for linearity, accuracy, precision, limit of quantitation, and robustness [1, 2]. Linearity, accuracy, and precision were found to be acceptable over the ranges 2.50–30.00 g mL^–1 for pioglitazone and 0.10–10.00 g mL^–1 for glimepiride.     

免疫法制备液相色谱生物样品的研究——血中沙丁胺醇的分析

用动物免疫法制备了免疫亲和柱纯化水溶性的沙丁胺醇血浆样品。琥珀酸酐交联沙丁胺醇和牛血清白蛋白获得抗原免疫家兔抗沙丁胺醇抗体——免疫球蛋白。琼脂糖Ｓｅｐｈａｒｏｓｅ４Ｂ与抗体交联制成免疫球蛋白亲和柱。对高效液相色谱法测定中的一般提取方法和固相小柱提取法作了比较，后者具有内源性杂质干扰少的优点，是生物样品预处理的一种有效的方法