A liquid chromatographic method for determination of theophylline in serum and capillary blood--a comparison.

A simple, fast and reliable liquid chromatographic method for the determination of theophylline in serum and capillary blood after a solid phase extraction is described for therapeutic drug monitoring. The employment of capillary blood permits the determination of an individual drug profile and other pharmacokinetic studies in neonates and infants. There were no differences in venous- and capillary-blood levels but these values compared poorly with those in serum. An adjustment of the results by correction of the different volumes of serum and blood by haematocrit was unsuccessful. Differences in the binding of theophylline to erythrocytes could be an explanation for the differences in serum at blood levels of theophylline.     

High-performance liquid chromatographic determination of trimethoprim in serum

A procedure for determining trimethoprim in serum is reported. It employs the same high-performance liquid chromatographic system described previously for measurement of anticonvulsants, barbiturates, theophylline, caffeine, acetaminophen, and chloramphenicol in serum. The sample preparation for trimethoprim is nearly identical. As a method extension, quantitation of serum trimethoprim on clinical specimens can be easily accommodated as required.     

反相高效液相色谱法测定人血清中茶碱,咖啡因浓度

本文采用反相高效液相色谱法测定了人血清中茶碱、咖啡因浓度。色谱柱：Ｈｙｐｏｒｓｌｌ－ＯＤＳ（２００×２．１），流动相：醋酸—醋酸钠缓冲液（ｐＨ４．５）：甲醇（７０∶３０ｖ／ｖ），检测波长２７０ｎｍ。本文方法简便、快速，结果令人满意。     

Improved liquid chromatographic determination of procainamide and N-acetylprocainamide in serum

A liquid chromatographic method for the determination of procainamide (PA) and N-acetylprocainamide (NAPA) in serum has been developed. This method utilizes isocratic conditions, ambient temperature, and a conventional fixed-wavelength 280-nm detector. Sample pretreatment involves extraction of PA and NAPA, along with p-amino-N-(2-dipropylaminoethyl)-benzamide hydrochloride as internal standard, into an organic phase and reextraction into an aqueous acidic phase. Using this sample pretreatment, interferences due to commonly used drugs are eliminated. The method accurately measures PA and NAPA to levels as low as 1 mg/L.     

The liquid chromatographic determination of theophylline in untreated plasma by simple direct injection

A liquid chromatographic method for determination of theophylline by direct injection of untreated plasma samples is described. Theophylline is detected without interference from related compounds such as paraxanthine. A precolumn venting technique is used which considerably increases column life. The lifetimes of the separation columns are unaffected by plasma injections whereas the precolumn has to be changed after 140 injections (10 mul of plasma). The peak purity of theophylline is examined spectrophotometrically. Determinations are performed by external standardization with recoveries close to 100% with a precision better than 2.3% (RSD).     

High-performance liquid chromatographic method for the determination of trace amounts of acetaminophen in plasma

A method is described for the rapid, sensitive, and precise quantitation of acetaminophen in human plasma. The assay involved a single acetonitrile extraction and high-performance liquid chromatographic analysis using a reverse-phase column, with a mobile phase of methanol and water. The limit of quantitation of acetaminophen by this method was 8 ng/mL; only 0.1 mL of the plasma sample was required for the determination. N-Propionyl-p-aminophenol was used as the internal standard.     

Rapid quantitative liquid chromatographic determination of caffeine levels in plasma after oral dosing

A simple method is described for the rapid, quantitative analysis of caffeine in human plasma. Caffeine levels present in plasma following drug administration were determined by high-performance liquid chromatography with UV detection at 273 nm after plasma protein precipitation. Caffeine was detectable at levels as low as 0.1 micrograms/mL. Mean recoveries of 98% with a coefficient of variation of 3% were obtained for plasma standards, in which concentrations ranged from 0.1 to 8 micrograms/mL. Interassay variability of the slope of the standard curve had a coefficient of variation of 3%. Application of this method during human bioavailability studies is described.     

Rapid and simple high-performance liquid chromatographic determination of felbamate in serum

An isocratic high-performance liquid chromatographic method for the quantitation of felbamate in serum is presented. The method is based on protein precipitation with acetonitrile and reversed-phase chromatography with spectrophotometric detection at 210 nm. The separation was performed on a Nova-Pak C18 column and the mobile phase consisted of acetonitrile-water (1:4, v/v). Phenobarbital was applied as an internal standard. The assay was linear over the concentration range 0.5-200.0 microg/ml (r = 0.9999). Intra-day and inter-day precision expressed by relative standard deviation is less than 3%. The percentage of recovery was 98.63 +/- 2.47. The method is suitable for drug level monitoring and for pharmacokinetic studies.     

高效液相色谱法测定人血清中伊曲康唑浓度

目的：建立了ＨＰＬＣ法测定血清样品中伊曲康唑的定量分析方法。方法：色谱条件：以ＺＯＲＢＡＸＴＭＣ１８（５μｍ,４．６×１５０ｍｍ）为色谱柱;乙腈水（６７．５∶３２．５）为流动相,检测波长２６３ｎｍ;用正庚烷∶异戊醇（９８．５∶１．５）作为提取剂。结果：三种浓度４０,８０,３００ｎｇ·ｍｌ－１回收率分别为１０５．０５％,１００．５７％,９７．９１％（ｎ＝６）;日内、日间ＲＳＤ分别为３．８３％,４．０５％,３．０９％及６．００％,４．９０％,４．７２％（ｎ＝６）。血清中药物的最低检测浓度为５ｎｇ·ｍｌ－１,在５～６００ｎｇ·ｍｌ－１血药浓度范围内线性关系良好,ｒ＝０．９９９５。结论：方法灵敏、准确、结果满意     

Simple high-pressure liquid chromatographic determination of trisulfapyrimidines in human serum

A simple and rapid high-pressure liquid chromatographic method was developed for the determination of sulfadiazine, sulfamerazine, and sulfamethazine in human serum. After the trichloroacetic acid precipitation of the serum proteins, an aliquot of the supernate is injected into a high-pressure liquid chromatograph equipped with a reversed-phase microparticulate column and a fixed wavelength UV detector. For each of the three components of trisulfapyrimidines, a linear calibration curve was observed in the 1-30-microgram/ml range, with the precision of the assay estimated to be +/- 2% (RSD). Preliminary pharmacokinetic data are also presented.     

高效液相色谱法测定人血清中氯林可霉素

本文研究建立了人血清中氯林可霉素的高效液相色谱测定法（ＨＰＬＣ），该方法在超低紫外（１９８ｎｍ）下测定，具有取样量小（２００μｇ），线性范围宽（０．５％～５０μｇ／ｍｌ）；灵敏度高，以３倍基线噪音计算，最低检测限可达０．０５μｇ／ｍｌ；重现性好，高中低３个质控样品批间ＲＳＤ％分别为１．９７、０．４０和２．１５，批内ＲＳＤ％分别为０．８０、０．４６和２．３３，平均回收率分别为１０１．８７，１００．３４％和９３．８１％；方法操作简便等特点，为测定血清中药物浓度，确定给药方案和治疗剂量，以及药物动力学分析和药效学评价提供了方法学基础     

Rapid, stability-indicating, high-pressure liquid chromatographic determination of theophylline, guaifenesin, and benzoic acid in liquid and solid pharmaceutical dosage forms.

Theophylline, guaifenesin, and benzoic acid were determined by reversed-phase high-pressure liquid chromatography without interference from active and/or vehicle decomposition. A degradation product of sucrose, 5-hydroxymethylfurfural, can be identified and quantified in liquid samples simultaneously.     

Specific high performance liquid chromatographic determination of quinidine in serum, blood, and urine

A reversed-phase high performance liquid chromatographic method for determination of quinidine in serum, blood, and urine has been developed. An alkylnitrile column is used with a mobile phase of acetonitrile in an acetate buffer. The method was rigorously tested and shown to be specific for quinidine using the following methods: comparison of capacity factors among methanolic reference standards of quinidine, known metabolites, and 36 other drugs; comparison of the quinidine capacity factor with the capacity factors from components in patient sera and urines, from which quinidine was selectively removed by thin-layer chromatography; and, correlation of quinidine concentrations in patient sera using ultraviolet absorbance versus fluorescence detection. Application of the method to a single-dose pharmacokinetic study, including serum protein binding and blood/serum concentration ratio measurements.     

Simultaneous liquid chromatographic determination of chloramphenicol and antiepileptic drugs (phenobarbital, phenytoin, carbamazepine, and primidone) in plasma

A method for the simultaneous analysis of chloramphenicol and four antiepileptic drugs (phenobarbital, phenytoin, carbamazepine, and primidone) in plasma by high-performance liquid chromatography (HPLC) is described. The method involves a preliminary extraction of 0.1 ml of plasma with diethyl ether containing phenacetin as an internal standard, chromatography with a reversed-phase column with a methanol-water mobile phase, and detection by measuring ultraviolet absorbance at 210 nm. The method demonstrated sufficient precision, sensitivity, and specificity: the recoveries of the drugs were greater than 95% with the exclusion of primidone (80.3%); the maximum within-day and day-to-day coefficients of variation for all drugs were less than 5%; the lower detection limits were 0.5 microgram/ml or less for all drugs analyzed; and six other antibiotics, phenylethylmalondiamide, carbamazepine-10,11-epoxide, and chloramphenicol esters did not interfere with the analysis. The HPLC method was tested for clinical applicability by analyzing plasma samples from a volunteer who received concurrent single doses of chloramphenicol, phenobarbital, and phenytoin. This method can be used for studying drug interactions between chloramphenicol and antiepileptic drugs and for monitoring the concentrations of these drugs in plasma when administered concurrently, to prevent concentration-related side effect(s) of each drug.     

HPLC法测定人血清及尿中美洛培南浓度

目的　建立测定人血清样品及尿样品中美洛培南的定量分析方法。方法　采用高效液相色谱法 ,以 μ- Bondapak C1 8柱 (3.9mm× 30 0 mm,10 μm)为色谱柱 ;甲醇∶ 5 mmol/ L 磷酸二氢钾缓冲液 (17∶ 83,v/ v)为流动相 ,p H2 .5 ,检测波长 30 8nm。结果　血清中美洛培南的回收率平均为 97.5 4 % (n=6 ) ;日内 ,日间RSD≤ 3.80 % ,在 1～ 10 0 mg/ L 血药浓度范围内线性关系良好 ,r=0 .9997。尿中美洛培南的平均回收率为96 .90 % (n=6 ) ;日内、日间 RSD<3.5 0 % ,在 5～ 10 0 mg/ L 尿药浓度范围内线性关系良好 ,r=0 .9994。结论该方法灵敏准确 ,适用于临床药代动力学的研究。     

High-performance liquid chromatographic method for the determination of colistin in serum

Inhalation therapy of colistin is widespread in patients with cystic fibrosis. To date, no pharmacokinetic data of colistin after inhalation are available. To optimize the inhalation therapy, pharmacokinetic data of colistin are necessary. In this study, the authors describe a chromatographic analysis for measurement of colistin concentrations in serum. After protein precipitation, the colistin sample is treated with orthophthalaldehyde for derivatization. The sum of the peak areas of the two main components of colistin (polymyxin E1 and E2) were used for quantitation. The performance of the analytical method was assessed by determining the lower limit of quantitation, the selectivity of the method, the intra-assay variation, the reproducibility, the interassay variation, and the accuracy. The lower limit of quantitation was 28 microg/L. Ceftazidime, aztreonam, piperacilline, or tobramycin showed no interference with the colistin assay. In a pilot study, the authors found a trough value of approximately 10 microg/L and peak values of approximately 100 microg/L after inhalation of 160 mg colistin in serum samples of a representative patient. These values show that the method can be used to design further experiments. The applicability of the method was also tested on urine and sputum samples. Colistin was detectable but further validation experiments are required to confirm the usefulness of the method in these biologic matrices. To the authors' knowledge this is the first study in which serum concentrations are described after inhalation of colistin in patients with cystic fibrosis.     

Reversed-phase high-performance liquid chromatographic determination of mitomycin C in human serum

A reversed-phase high-performance liquid chromatographic method is presented by which the cancer chemotherapeutic agent, mitomycin C, may be measured in human serum. A mobile phase of methanol:water (35:65) passed through a mu-Bondapak C-18 column at a rate of 1.0 ml/min produced a sharp, symmetrical band for mitomycin C. An improved serum extraction procedure, using a reversed-phase sample preparation cartridge, proved to be efficient and reproducible. Recovery over a concentration range of 10-100 ng/ml was 81.6% with a between-day coefficient of variation of 4.6% (n = 5). The within-day coefficient of variation at 50 ng/ml was 5.6% (n = 10). Ultraviolet detection at a wavelength of 365 nm was sensitive to serum concentrations of 10 ng/ml. Serum concentration-time course data from lung cancer patients receiving mitomycin C by rapid intravenous injection are presented.     

Method for screening and quantitative determination of serum levels of salicylic Acid, acetaminophen, theophylline, phenobarbital, bromvalerylurea, pentobarbital, and amobarbital using liquid chromatography/electrospray mass spectrometry

We investigated a method for the simultaneous screening, identification, and quantitative determination of salicylic acid, acetaminophen, theophylline, barbiturates, and bromvalerylurea, drugs that frequently cause acute poisoning in Japan and therefore require rapid analysis for effective treatment in the clinical setting. The method employs liquid chromatography/electrospray mass spectrometry (LC/MS) of solid-phase extracted serum samples. For LC/MS ionization, the electrospray-ionization method was used, with acetaminophen in the positive-ion mode, and salicylic acid, theophylline, phenobarbital, bromvalerylurea, pentobarbital, amobarbital, and o-acetamidophenol (internal standard) in the negative-ion mode, the base ions were used in each case for quantitative analysis. Quantitation was possible for the following sample concentration ranges: salicylic acid and acetaminophen, 100 to 5 microg/ml; theophylline, 100 to 0.5 microg/ml; and phenobarbital, bromvalerylurea, pentobarbital, and amobarbital, 100 to 1 microg/ml. Using full-scan mass spectrometry, the lower detection limits of 1 microg/ml for salicylic acid and acetaminophen, 0.1 microg/ml for theophylline, and 0.5 microg/ml for phenobarbital, bromvalerylurea, pentobarbital, and amobarbital were adequate for identifying acute poisoning. When each compound was added to serum to a final concentration of 5 microg/ml and solid-phase extraction was performed using Oasis HLB 1-cc (30-mg), the mean recovery rate of each compound was 89.2 to 96.1% (n=5), and the coefficients of variation of the intraday and interday assays were 3.55 to 6.05% (n=5) and 3.68 to 6.38% (n=5), respectively, which are acceptable. When this method of analysis was applied in testing the sera of a female patient who had consumed a large amount of an unknown commercial drug, salicylic acid and bromvalerylurea were identified, and the treatment strategy could be determined in accordance with the serum concentration of those drugs.