Determination of Cefpirome in Human Plasma by High-Performance Liquid Chromatography

Abstract

Cefpirome is an investigational third-generation cephalosporin, which appears promising for the treatment of various pediatric infections. A high performance liquid chromatographic method was developed to measure cefpirome in small volumes of plasma for conducting pharmacokinetics studies in infants and children. the assay involved precipitation of plasma proteins with acetonitrile, using cefaclor as an internal standard. Chromatographic separation was accomplished using a reverse-phase     

Sensitive Determination of Piritramide in Human Plasma by High-Performance Liquid Chromatography

Abstract

A selective and sensitive method for the determination of piritramide in human plasma is described. After addition of 50 μl of 2 M ammonia and 20 μl of aqueous promethazine solution (100 ng/10 μ1) as an internal standard, 1 ml of plasma was extracted with 5 ml of toluene (extraction efficiency: 93.9 × 2.6%; mean × S. D.; n = 5). HPLC was performed with a phenyl hypersil NC-04 column, particle size 5 μm, 250 × 4 mm I. D.; mobile phase: 8 parts of acetonitrile and 2 parts of 10 mM potassium phosphate buffer (pH 3. 3). The flow rate was set to 2 ml/min and the column temperature was 22°C. The assay was linear in a concentration range of 3.75 ? 3000 ng/ml (r = 0.999), with a lower limit of detection of 3 ng/ml. The precision was determined using spiked plasma samples (15 ng/ml; 300 ng/ml), with coefficients of variation of 6.1 and 5.9% (intraday; n = 5) and 6.5 and 0.2% (interday; n = 3). In the range of 5.6 ? 1500 ng/ml, the accuracy of the assay was 2.82%. The method was used for the determination of piritramide plasma concentrations in patients receiving intra- or postoperative analgesia.     

Individual Carotenoid Determinations in Human Plasma by High-Performance Liquid Chromatography

Abstract

A high-performance liquid chromatographic technique is described to quantify beta carotene from alpha carotene and lycopene in human plasma. Total analysis time is 14.5 min. A reverse-phase column was employed with a mobile phase composed of 65% acetonitrile: tetrahydrofuran (90:10, v:v) in methanol. Use of the internal standard, beta-apo-8- carotenoic ethyl ester permitted a reliable way to quantify potential losses in plasma extractions. Plasma beta carotene levels obtained from subjects several days after supplement use were observed to increase three-fold or more.     

Determination of Plasma Levels of Bupivacaine by High-Performance Liquid Chromatography

Abstract

We evaluate a method for determination of bupivacaine using HPLC, and the possibility of pharmacological interferences produced by seven commonly used drugs administered before, during and after surgery: diacepam, midazolam, epinephrine, naloxone, flumacenil, atropine and ephedrine. The method has an average recovery of 102.8 +/? 5.4%. The detection limit is 0.125 μg/mL. The within-day coefficient of variation is 5.88% and the between-day coefficient of variation is 15%. We haven't found drug interferences at generally encountered serum concentrations.     

Determination of Acyclovir in Human Serum by High-Performance Liquid Chromatography

Abstract

A method was developed for determination of concentrations of acyclovir in serum. Serum proteins were precipitated with equal part of 5% perchloric acid. High-performance liquid chromatography was used for separation from endogenous compounds and detection was done with spectrophotometry. The assay is simple and precise and seems well suited for pharmacokinetic studies.     

高效液相色谱法测定血清中茶碱浓度

采用高效液相色谱,分析柱：３μｍ,３．３ｃｍ＊４．６ｍｍ,Ｉ．Ｄ（Ｐｅｒｋｉｎ Ｅｌｍｅｒ,ＵＳＡ）;预柱：１０μｍ,１ｃｍ＊２．１ｍｍ,Ｉ．Ｄ（Ｐｅｒｋｉｎ ＥＬｍｅｒ,ＵＳＡ）;以乙酰氨基酚为内标对氯仿－异丙醇（９５：５,Ｖ／Ｖ）提取样品进行了分析,流动相：０．１ｍｏｌ／Ｌ醋酸缓冲液（ＰＨ＝４．５）－甲醇（７０：３０,Ｖ／Ｖ）;检测波长：２７０ｎｍ;流速０．５ｍＬ／ｍｉｎ,３ｍｉｎ即完成一次茶     

Determination of Bumetanide in Human Plasma and Urine by High-Performance Liquid Chromatography with Fluorescence Detection

Abstract

This paper describes a new high-pressure liquid chromatographic method used for quantitation of bumetanide in urine and plasma. Compared to previously reported methods, this assay offers the advantages of increased sensitivity, shortened sample preparation time and decreased instrumentation requirements. After addition of the 4-benzyl derivative of bumetanide as the internal standard, both urine and plasma underwent a single extraction with ethyl acetate at an acidic pH. The organic extract was separated, evaporated to dryness, reconstituted with methanol, and chromatographed using a reversed-phase C-18 radial compression cartridge with fluorescence detection. Sensitivity limits are approximately 1 ng of bumetanide per mL of plasma, with a coefficient of variation for identical samples never exceeding 6%. The method lends itself to pharmacokinetic and pharmacodynamic studies of bumetanide in humans following single therapeutic doses.     

Determination of Carvedilol in Human Plasma by High-Performance Liquid Chromatography Applying On-Line Deproteination and Column Switching

An HPLC-column switching method has been developed and validated for the determination of carvedilol in human plasma. 20 μL plasma was injected onto a Brownlee C8 column and the high molecular weight proteins were eluted isocratically. Carvedilol was separated from the majority of the components by a linear acetonitrile gradient. The fraction containing carvedilol was switched on-line onto a LiChrospher RP 18 column and separated isocratically from accompanying compounds applying 0.1 M triethylamine-methanol-acetonitrile = 17: 18:19 (v/v/v). The influence of pH and temperature on retention was investigated on both columns. No interference from other plasma components was observed. Reproducibility of the complete method was better than 4% and the limit of quantitation was 0.8 ng mL^?1.     

Tocainide Determination by High-Performance Liquid Chromatography

Abstract

Tocainide has been assayed after serum deproteinization with acetonitrile by HPLC. The pH was critical in separating the drug from other interferences in the serum. The method is simple and fast.     

High-Performance Liquid Chromatographic Determination of Acetazolamide in Human Plasma

Abstract

A simple, rapid and specific HPLC method has been developed to determine acetazolamide concentrations in human plasma. The assay procedure requires only 250 μl of sample with direct injection of the organic supernatant after protein precipitation with acetonitrile. Chlorothiazide was used as an internal standard. A reversed-phase C₁₈ μBondapak column was employed for the chromatographic separation. The eluent was monitored at 265 nm using a UV variable wavelength detector. The retention times for acetazolamide (ACZ) and chlorothiazide (CTZ) were 6 and 8 min respectively. A linear relationship (r).995) was obtained over the 1-20 μg/ml concentration range. The limit of sensitivity for ACZ was 0.5 μg/ml, with greater than 85% recovery of ACZ and internal standard. The method was applied to human plasma samples obtained after administration of a 250 mg acetazolamide tablet.     

Simultaneous Determination of Diazepam and its metabolites in Plasma by High-Performance Liquid Chromatography

Abstract

A reversed phase high-performance liquid chromatographic method (HPLC) for the simultaneous determination of diazepam and its three active metabolites, nordazepam, oxazepam and temazepam, in plasma was proposed. The compounds were isolated by solid-phase extraction. The chromatographic mobile phase was metanol-water (55:45, v/v) at a flow rate of 1 mL/min. UV detection was performed concurrently at 240 and 254 nm.     

Measurement of Nicotine in Plasma by High-Performance Liquid Chromatography

Abstract

A new procedure has been developed to measure nicotine in blood plasma by high-performance liquid chromatography (HPLC). Nicotine is extracted from plasma by elution with cholorform. Final determination is achieved by isocratic HPLC with ultraviolet detection. Twenty microliters of plasma extract is deluted over a silica column at a flow rate of 1.0 ml/min with a dioxane:isopropanol:NH₄OH (80:3.0:0.4) mobile phase. The procedure is sensitive to 0.05 ug of nicotine per ml of plasma and is linear within the range of 0.05 to 10.0 ug/ml of plasma. When a known amount of nicotine was added to plasma, the concentration of nicotine measured averaged 99.9 + 3.9 (S.D.)% of the known concentration. The within-sample coefficient of variation was 3.9%     

Determination of Suramin in Plasma and Urine by Ion-Paired Reverse-Phase High-Performance Liquid Chromatography

Abstract

A high-pressure liquid chromatographic (HPLC) assay has been developed for the quantification of the anti-viral drug suramin (SUR) in human plasma and urine. This assay is simple and accurate, using an isocratic mobile phase in a reverse-phase ion-pairing mode.

This assay was developed for the determination of high levels of suramin in the urine and plasma of patients being treated for the acquired immunodefficiency Syndrome (AIDS). The limit of detection of this assay was 0.25 μg/mL. Congo red (CR) was used as the internal standard with a retention time of 5.9 min, while suramin had a retention time of 13 min.     

The Rapid Determination of Neopterine in Human Urine by Isocratic High-Performance Liquid Chromatography

Abstract

An isocratic high-performance liquid chromatography method is described for the determination of Neopterine eliminated in human urine, using a μ-Bondapak C₁₈ column (300 × 3.9 mm I.D.) and a strongly polar phosphate buffer (pH 6.2) for elution. This analysis requires only 15 minutes and allows very good reproduc-tibility of retention times. This method is well-suited for automation and routine clinical laboratory in order to quantify human urinary Neopterine in healthy subjects and in subjects with malignant disorders.     

Separation and Determination of Bile Acids in Human Bile by High-Performance Liquid Chromatography

Abstract

A method for simultaneous determination of major bile acids in human bile is described. The unconjugated, glycine- and taurine-conjugated bile acids are extracted with Sep-pak C¹⁸ and separated into groups by ion-exchange chromatography on a lipophilic gel. Subsequently, resolution of each group into ursodeoxycholate, cholate, chenodeoxycholate, deoxycholate and lithocholate is attained into two stages by high-performance liquid chromatography on a Radial-PAK A column. First, 0.3% ammonium phosphate (pH 7.7)/acetonitrile (19:8, v/v) is used for separation of the latter three as a mobile phase. Ursodeoxycholate and cholate are efficiently separated in 0.3% ammonium phosphate (pH 7.7)/acetonitrile (23:8, v/v). The present method is applicable to quantitation of bile acids in human bile with satisfactory accuracy and precision.     

Analysis of Norethindrone In Plasma by High-Performance Liquid Chromatography

Abstract

A sensitive specific high-performance liquid chromatographic procedure for the determination of norethindrone in plasma is described. The organic solvent extract from plasma is chromatographed on a reversed phase column using a high-performance liquid chromatograph fitted with an ultraviolet detector (254 nm); quantitation from plasma samples containing 2 ng/ml norethindrone is reported. Metabolites and endogenous substances do not interfere with the assay. The determination of norethindrone concentrations in plasma following administration of single oral dose to a mini-pig is described.     

Determination of Monobromobimane-Labeled Phytochelatins by High-Performance Liquid Chromatography

A new method for phytochelatins by high-performance liquid chromatography (HPLC) was developed based on a condensation reaction with monobromobimane to produce fluorescent derivatives. Glutathione, H-(γ-glutamic acid-cysteine)₂-glycine-OH, H-(γ-glutamic acid-cysteine)₃-glycine-OH, H-(γ-glutamic acid-cysteine)₄-glycine-OH, H-(γ-glutamic acid-cysteine)₅-glycine-OH, and H-(γ-glutamic acid-cysteine)₆-glycine-OH were well separated, with retention times between 14.68 and 22.0 min. The HPLC method had good linearity (r < 0.9991) between 0.1 mg L^?1 and 100 mg L^?1. The limits of quantification for the analytes (S/N = 3) were 0.08, 0.3, 0.05, 0.3, 0.5, and 0.8 mg L^?1, respectively. The recoveries were between 83.0% and 101.33% with relative standard deviations less than 2%. The reported method is simple, accurate, and suitable for the determination of phytochelatins.     

Rapid Quantitation of Verapamil in Plasma by High-Performance Liquid Chromatography

Abstract

A simple and sensitive liquid chromatographic assay procedure using a fluorescence detector for the quantitative determination of verapamil in plasma without extraction was developed. After precipitating the protein with acetonitrile, the resulting supernatant liquid was injected onto the column for analysis. Chromatographic separation was achieved on C₁₈ reversed phase column and the eluting solvent was the isocratic mixture of methanol, acetonitrile and pH 3.0 glycine buffer (1:4:5). With this mobile phase the drug and its internal standard were well separated from the interference of the plasma sample. The average recovery of verapamil from 3 replicate samples of different concentration (100–600 ng/mL) were 95.5 ± 5.68%. The minimum amount of verapamil detectable by this method was 40 ng/mL of sample. The elimination half-life (β-phase) of this drug in rabbits was found to be 3.7 hours.     

高效液相色谱法测定血浆中舒必利浓度

讨论了测定舒必利血药浓度的反相高效液相色谱方法。选用美国Ｂｉｏ－Ｒａｄ７００型高效液相色谱仪,ＲＰ－３１８色谱柱,ＵＶ检测波长２９０ｎｍ,流动相为甲醇－水－冰醋酸（６０３０１）,内标物为胃复安。回收率为９７．９５％～９９．９６％,ＲＳＤ为２．６％～５．１％,最低检出浓度１．０ｍｇ／Ｌ,线性范围５～１００ｍｇ／Ｌ。测定３０例服药病人的血药浓度,得到了满意的结果。