High Pressure Liquid Chromatographic Determination of Mecillinam in Human Plasma and Urine

Abstract

A simple, specific, rapid and sensitive method for the analysis of mecillinam in plasma and urine using high pressure liquid chromatography is described. The assay is performed by direct injection of a plasma protein free supernatant or a dilution of urine. A μBondapak phenyl column with an eluting solvent of 16% CH₃CN-0.2% H₃PO₄ was used, with UV detection of the effluent at 220 nm. Desacetyl-cephalothin was used as the internal standard and quantitation was based on peak height ratio of mecillinam to that of the internal standard. The lowest concentration detectable without extraction was 0.25 μg/ml for plasma and 8.9 μg/ml for urine. No interference from plasma and urine was noted.     

High Performance Liquid Chromatographic Determination of Pentamidine in Plasma

Abstract

A high performance liquid chromatographic method for quantitating pentamidine in plasma has been developed. Sample clean-up involved precipitating plasma with acetonitrile containing the internal standard, hexamidine. The supernatant was passed through a C₈ Bond Elut column and eluted with a methanolic solution of sodium 1-heptanesulfonate. The eluate was then analyzed on an Altex C₈ column with a mobile phase consisting of 45% CH₈CN, 0.02% detramethylammonium chloride and 0.1% H₃PO₄. Using fluorescence detection (EX: 275 nm and EM: 340 nm), the detection limit was 1.25 ng/ml for 0.5 ml of plasma. The coefficients of variation for interday and intraday were around 10%.     

Rapid High Performance Liquid Chromatographic Determination of Ampicillin in Human Urine

Abstract

A rapid, sensitive and specific HPLC assay for the determination of ampicillin in human urine is developed.

Ampicillin was directly measured in human urine at 225 nm using a reversed phase column (Synchropack RP-P) and a mobile phase composed of (1:9 methanol-sodium acetate solution, 0.01 M, pH 4). The analysis required no longer than 10 min. Linear correlation between the peak height ratio of ampicillin to cefoxitin sodium (internal standard) and ampicillin concentration in urine over the range 10–100 μg ml^?1 was obtained. The developed method proved to be advantageous as it monitors ampicillin level in urine. Moreover, the urinary excretion of ampicillin in human subjects after an oral administration of 500 mg ampicillin capsules was established using the proposed method.     

High Performance Liquid Chromatographic Determination of Oxamniquine in Plasma Samples

Abstract

A sensitive and reliable liquid chromatographic assay procedure for the quantitation of oxamniquine in plasma or urine was developed. Chromatographic separation was achieved on a reversed-phase phenyl colum using U.V. Detection at 254 nm. The eluting solvent was the mixture of 0.05 M acetate buffer pH 5 and acetonitrile (3:7). With this mobile phase the drug and its external standard were well separated from the interference of the blank samples. The average recovery of oxamniquine from 3 or more replicate dog plasma samples of different concentration (0.125 ? 4.00 μg/ml) was 95.5% and its coefficient of variation was 4.17%. The reproducibility of the assay was confirmed by the analysis of variance test for the slopes of the three standard plots obtained from plasma samples at three different occasions (F=4.2, p > 0.01). The detection limit for plasma samples was approximately 20 ng/ml. The method was applied to measure the plasma level vs, time profile of this drug following a single bolus intravenous dose of 16 mg/kg to a dog.     

High Performance Liquid Chromatographic Determination of Amiodarone in Plasma and Tissues

Abstract

A simple and rapid high-performance liquid chromatographic (HPLC) method for the determination of amiodarone (AD) in plasma and tissues was developed. The method involved deproteinization of plasma or homogenized tissue with acetonitrile containing an internal standard (N-Cetylpyridinium chloride) followed by reversed phase chromatography using μ bondapack C₁₈ column (10μm) with a mobile phase consisting of acetonitrile - methanol - sodium dihydrogen phosphate buffer (70:10:20%, v/v), the pH adjusted to 4.0 and pumped at flow rate of 1.0 ml/min. The column effluent was monitored at 242 nm. A linear relationship was obtained between peak height ratios (drug to internal standard) versus drug levels over the concentration range of 50–750 ng/ml. The detection limit of AD in plasma and tissues by this method was 20 ng/ml.     

Determination of Chlormezanone in Plasma and Urine by High Performance Liquid Chromatography

Abstract

A reversed-phase high-performance liquid chromatographic (HPLC) method with UV detection was developed for quantifying chlormezanone in plasma and urine. an extraction step was needed to avoid endogenous interferences especially in urines and led to an average recovery of 90%. the sensitivity limit was 20 ng/ml in both plasma and urine. the method was reproducible with intra- and inter-assay coefficients of variations below 5%. This method was applied to the determination of plasma and urine levels during a pharmacokinetic study in the elderly. It was found suitable to follow the concentrations as long as 120 h after a single oral administration of 400 mg chlormezanone.     

Determination of Saccharin in Plasma and Urine by High Performance Liquid Chromatography

Abstract

A sensitive and specific high performance liquid chromatographic (HPLC) assay for the determination of saccharin in plasma and urine was developed. Saccharin is extracted into diethyl ether at acid pH, evaporated, and reconstituted prior to instrumental analysis. Overall recovery of saccharin is 86.9 + 8.6% and the sensitivity limits of detection is 0.15 μg per ml of plasma or urine using a fluorescence detector. The sensitivity limit in plasma can be extended to 20 ng per ml by use of a 2 ml assay volume and detector attenuation. The assay was used for the determination of saccharin in plasma and urine of rats following oral doses of 5 mg/kg.     

高效液相色谱法测定家兔血浆中桂皮酸的浓度及其药代动力学初探

 建立了采用高效液相色谱(HPLC)测定家兔血浆中桂皮酸含量的方法,并应用此法进行了桂皮酸的药代动力学研究。 采用的色谱柱为Kromasil C18柱(250 mm×4.6 mm i.d.,5 μm)；流动相为甲醇-乙腈-水-冰醋酸(体积比为10∶22∶55 ∶0.5),流速0.8 mL/min；检测波长为270 nm;柱温为室温；内标物为苯丙酸。实验结果表明,低、中、高浓度的提取回 收率分别为84.9%,84.4%,87.7%,方法回收率分别为98.4%,99.2%,100.1%,相对标准偏差(RSD)分别为5.5%,3.6%,3.7%, 日内及日间测定值的RSD均小于6%。所建立的HPLC方法灵敏、专一、准确、精密,可作为桂皮酸在家兔体内药代动力学研 究的检测手段。口服冠心苏合丸和冠心苏合胶囊后,桂皮酸在家兔体内的代谢呈一级吸收双室模型。     

High Performance Liquid Chromatographic Separation and Determination of Ciprofloxacin and its Metabolites in Urine

An improved HPLC procedure was described for separation of ciprofloxacin and its four metabolites in urine using the reversed phase chromatography. For determination of the optimum condition, the effect of ion pairing reagents was investigated as a view point of its type and concentration.     

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。     

High Performance Liquid Chromatographic Determination of (-)-N-Formylnorephedrine in Plasma

Abstract

An HPLC procedure for the detection and quantitative estimation of (-)-N-formylnorephedrine in rabbit plasma had been developed. The procedure involved the extraction of (-)-N-formylnorephedrine from plasma spiked with the internal standard (phenacetin), using ethyl acetate. The ethyl acetate extract is evaporated under nitrogen and the residue is reconstituted in water and injected onto the column. A u-Bondapak-C18 column 30 cm × 3.9 mm ID was used. The mobile phase is 20% acetonitrile in water; at a flow rate of 1.5 ml/min and uv detection at 256 nm. A linear relationship between concentration and peak height ratio (I/internal standard) was obtained (r = 1.00). The reported procedure allows the measurement of (-)-formylnorephedrine in concentrations as low as 150 ng/ml of plasma with total procedure time of about 10 min. The applicability of the procedure to pharmacokinetic studies is illustrated and metabolites are shown not to interfere with the assay procedure.     

A Sensitive High Performance Liquid Chromatographic Determination of Clopamide in Human Plasma

Abstract

A simple and sensitive high-performance liquid chromatographic method for quantitation of clopamide in human plasma has been developed. the assay uses a reversed-phase C18 microbore column (2 mm I.D. × 100 mm) packed with 5 μm ODS Hypersil. the chromatographic separation was achieved by using an isocratic mobile phase comprising acetonitrile-10 mM phosphate buffer pH 4 (17:83, v/v) at a flow rate of 0.5 ml/min. the eluant was monitored by a UV detector operating at 241 nm. the assay was based on an organic extraction before chromatographic separation. to 1 ml plasma sample, 100 μl of the internal standard, methylparaben (300 ng/ml), and 8 ml of diethyl ether were added. the samples were shaken and centrifuged, the organic layer was then transferred to a tapered centrifuge tube and evaporated to dryness. the residue was reconstituted and injected onto the HPLC column. the inter-and intra-assay coefficients of variation were found to be less than 10%. the lowest limit of detection for clopamide in plasma was 5 ng/ml. the method is sensitive, specific and allows for routine analysis in the pharmacokinetic studies.     

High Performance Liquid Chromatographic Analysis of Cepoperazone in Serum and Urine

Abstract

A high performance liquid chromatographic method was developed for the quantitative analysis of cefoperazone in serum and urine. Standard curves were linear over the range of concentrations 2–30 μg/ml and a good correlation was established between the amount of cefoperazone injected and peak height. The mean percentage analytical recovery of cefoperazone was 96.3% and the mean within day coefficient of variation in serum was 2.8%. Serum and urine components, as well as several beta-lactam antibiotics, did not interfere with the measurement of cefoperazone. This is a rapid, reproducible, and sensitive assay suitable for use in pharmacokinetic studies.     

A Validated Ion-Pairing High Performance Liquid Chromatographic Method for the Determination of Enoxacin and its Metabolite Oxo-Enoxacin in Plasma and Urine

Abstract

A rapid, sensitive, and specific determination of enoxacin and its principal metabolite, oxo-enoxacin, in plasma and urine is described. the method, which employs the structurally related compound ciprof loxac in as internal standard, involves a protein precipitation step for plasma and solid-phase extraction for urine. Liquid chromatographic analysis is carried out on a C-18 bonded silica column; the mobile phase consists of 0.1 M citric-acid/acetonitrile employing ammonium perchlorate and tetrabutyl-ammonium hydroxide as ion-pairing agents. Quantitation is performed by UV-detection at 340 nm.

The analytical method was validated by examining the performance characteristics specificity, linearity, precision, accuracy, sensitivity, and recovery. Enoxacin calibration curves were linear between 0.02 and 3.2 μg/ml of plasma and from 0.5 to 125 μg/ml of urine. Limits of quantitation in plasma and urine were 0.01 and 0.5 μg/ml, respectively. For oxo-enoxacin, linear of calibration curves were obtained i n the range 0.05 to 1.6 μg/ml (plasma) and 1 to 50 μg/ml (urine); the respective quantitation limits were approximately 0.02 and 1 μg/ml.

The present assay procedure has been applied to monitoring plasma and urine concentrations in several pharmacokinetic studies in humans and different animal species.     

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     

High Performance Liquid Chromatographic Determination of Nordihydroguaiaretic Acid

Abstract

A high performance liquid chromatography (HPLC) method was developed for the detection and quantitation of nordihydroguaiaretic acid (NDGA). Very low concentrations of NDGA in various extracts are detectable, thus making the method more sensitive than other previously reported analytical techniques. NDGA was extracted from leaves of Larrea divaricata as well as from rodent food containing NDGA. Since rats are fed NDGA in studies that examine the development of renal cystic disease, we modified extraction procedures to permit isolation of NDGA from tissue and serum samples.     

High Performance Liquid Chromatographic Determination of Emetine in Corn

Abstract

A High performance liquid chromatographic (HPLC) method for the quantitative analysis of emetine in corn is described. Corn kernels are removed from the ears, blended, and extracted with methanol. The extract is filtered through a 0.45 um Acrodisc filter and analyzed by HPLC using a LC-18-DB column. For detection, a fluorescence detector set at excitation of 285 and emission at 316 nm is used. The recoveries of samples fortified between 0.1 ppm to 20 ppm with emetine ranged from 95.5% to 103.3%.     

High Performance Liquid Chromatographic Analysis for Free Valine in Plasma

Abstract

A precolumn derivatization method is presented with the use of a fluorescent derivative, 1-dimethylaminonaphhalene-5-sulfonyl-chloride, dansyl chloride, for the detection of free valine in plasma. Dansylated amino acids were determined in deproteinized samples by reverse-phase liquid chromatography. The level of detection is 100 femtoraoles (10^?15). Sample preparation required precipitation of proteins with trichoroacetic acid and removing the excess acid with water saturated ether. The deproteinized sample was adjusted to pH 9.0 and reacted with dansyl chloride. The dansylated products were detected by ultraviolet and fluorescence spectrometry. Elution time for valine subsequent to injection is 25 minutes, while the total assay requires less than 50 minutes.     

高效液相色谱法测定人血浆及尿液中头孢呋辛和舒巴坦

建立反相HPLC-UV法同时测定人血浆及尿中头孢呋辛(CXM)和舒巴坦(SUL)的方法.采用Welch Materials XB-C18分析柱(150 mm×4.6 mm,5 μm ) ,流动相为乙腈-0.01 mol/L KH2PO4 (血浆测定15∶ 85(V/V),尿样测定10∶ 90(V/V),含0.04%三乙胺,以H3PO4调节至pH 3.2),流速1.0 mL/min,紫外检测波长SUL为220 nm、CXM及内标咖啡酸为274 nm.血浆样品在酸性条件下用乙醚提取浓集后进样,以内标法进行定量分析.尿样稀释后直接进样,以外标法进行定量分析.血浆测定中SUL和CXM浓度分别在0.25～200 mg/L和0.5～400 mg/L范围内线性良好; 萃取回收率分别为75.6%～88.1%和68.6%～77.4%; 批内与批间RSD均小于9%,方法回收率分别为94.6%～113.6%和91.9%～101.8%.尿样中SUL和CXM浓度分别在5～5120 mg/L和10～10240 mg/L范围内线性良好; 批内与批间RSD均小于3%; 方法回收率分别为92.9%～111.1%和98.0%～105.3%.本方法快速简便, 灵敏准确,可用于同时测定血浆及尿中SUL和CXM浓度,亦可用于药代动力学、生物利用度研究.     

High Performance Liquid Chromatographic Determination of Triazolam in Human Serum

Abstract

A high performance liquid chromatographic method which utilizes UV-detection has been developed for the sensitive and specific determination of triazolam in human serum. Using 8-chloro-6-phenyl-l-ethoxymethyl-4H-s-triazolo[4, 3-a][1, 4]benzodiazepine as an internal standard, serum samples were buffered with 2 ml of 4M NaOH and extracted twice with 5 ml aliquots of toluene. The combined toluene extracts were evaporated to dryness and the residue dissolved in the chromatographic mobile phase. The samples were chromatography on a microparticulate reverse-phase column using a 0.06M acetic acid:acetonitrile (61:39) mobile phase. Known metabolites of triazolam did not interfere in the analysis. A linear relationship between peak height ratios and concentrations was observed, with the lower limit of detection being approximately 1 ng of triazolam. The utility of the method was demonstrated by administering therapeutic doses of the drug to human volunteers and monitoring serum triazolam concentrations as a function of time.