Clematis huchouensis Tamura: a traditional Chinese herbal medicine and its quality control using a high performance liquid chromatography technique

A simple, specific and reliable high performance liquid chromatography (HPLC) method has been developed and validated for study of fingerprint chromatograms of extracts from the whole plant of Clematis huchouensis Tamura (CHT) for quality control of a traditional Chinese medicinal (TCM) herb. An Agilent C18 column was used to separate extracts in this protocol and detection was made by ultraviolet absorbance at 340 nm. The column temperature was maintained at 25 degrees C. A mobile phase consisting of (a) water (with 30 mM KH2PO4) and (b) CH3CN, (c) CH3OH was found to be suitable for this separation at a flow rate of 0.8 microl min(-1) with gradient elution. Under the described conditions, a fingerprint profile of 8 compounds was collected within 35 min, which made the HPLC method unique and interesting. The fingerprint chromatograms had good stability, precision and reproducibility. Moreover, eco-climatic (habitat) effects were studied by comparison of fingerprint chromatograms obtained from extracts of CHT collected from two habitats, with rutin as a reference marker peak. The protocol developed is quite suitable for differentiation of extracts of CHT and can be used as a quality control method for this herb and a model for other herbal drugs.     

去甲斑蝥素片的高效液相色谱质量检测

目的 研究去甲斑蝥素片的质量控制方法。方法采用HPLC法,色谱柱Polarls C_(18)柱(5 μ,4.6mm×250mm),检测波长为211 um,流动相为:水:乙醇(85:15),以磷酸调节pH至3.1。结果 去甲斑蝥素在25～1000mg·L~(-1)范围内呈线性系统,r=0.9 999,最低检出限为0.2mg·L~(-1),平均回收率为100.84％,平均RSD为1.335％。结论 该方法快速、准确,重现性好,适用于该制剂的含量测定。     

Determination of bevantolol in human plasma by high performance liquid chromatography using solid phase extraction technique

A method was developed and fully validated for the determination of bevantolol, an adrenergic-receptor blocker, in human plasma. Bevantolol and betaxolol as internal standard (I.S) were extracted from 1 mL of human plasma by solid phase extraction technique using Sep-pak silica cartridge. Chromatographic separation was accomplished under isocratic conditions using a reverse-phase C8 analytical column and mixture of dibasic ammonium phosphate (pH 5.7; 50 mM)-acetonitrile (75:25, v/v) as mobile phase, with a detection wavelength at 220 nm. The method was proved to be specific by testing six different human plasma sources. Linearity was established for the concentration ranges of 40-1600 ng/mL with correlation coefficent of 0.9995. The lower limit of quantification 40 ng/mL with precision of 10.9% as C.V%.     

High performance liquid chromatography used for quality control of Achyranthis Radix

To establish a standard of quality control and to identify reliable Achyranthis Radix, three phytoecdysones including ecdysterone (1), 25R-inokosterone (2) and 25S-inokosterone (3) were determined by quantitative HPLC/UV analysis. Three phytoecdysones were separated with an YMC J'sphere ODS C(18) column (250 mm × 4.6 mm, 4 μm) by isocratic elution using 0.1% formic acid in water and acetonitrile (85:15, v/v%) as the mobile phase. The flow rate was 1.0 mL/min and the UV detector wavelength was set at 245 nm. The standards were quantified by HPLC/UV from Achyranthes bidentata Blume and Achyranthes japonica Nakai, as well as Cyathula capitata Moq. and Cyathula officinalis Kuan, which are of a different genus but are comparative herbs. The method was successfully used in the analysis of Achyranthis Radix of different geographical origin or genera with relatively simple conditions and procedures, and the assay results were satisfactory for linearity, recovery, precision, accuracy, stability and robustness. The HPLC analytical method for pattern recognition analysis was validated by repeated analysis of eighteen A. bidentata Blume samples and ten A. japonica Nakai samples. The results indicate that the established HPLC/UV method is suitable for quantitation and pattern recognition analyses for quality evaluation of Achyranthis Radix.     

Simultaneous determination of six active components in crude and processed Fructus Corni by high performance liquid chromatography

A simple and rapid HPLC method was established for simultaneously determining six active components in Fructus Corni. The six components were separated on an Agilent Zorbax Extend C(18) column (250mmx4.6mm, 5mum) and detected by diode array detector (DAD). Mobile phase was composed of (A) aqueous phosphoric acid (0.1%, v/v) and (B) acetonitrile phosphoric acid (0.1%, v/v) using a gradient elution. Analyses were performed at 30 degrees C with a flow rate of 1.0mL/min and UV detection at 218nm, 240nm and 284nm. All calibration curves showed good linear regression (r(2)>/=0.9999) within tested ranges. The LOD and LOQ were 0.11-1.69mug/mL and 1.48-16.60mug/mL, respectively. Overall intra-day and inter-day variations were less than 4.72%, and the average recoveries were 97.97-102.51% for the analytes. The developed method can be applied to the intrinsic quality control of Fructus Corni.     

Determination of meglumine in pharmaceutical formulations using high performance liquid chromatography

Four different approaches were followed for the development of a HPLC method for the determination of meglumine in solid dosage formulations: derivatization of meglumine prior to HPLC analysis, the use of an ion-pairing reagent in the mobile phase, the use of charged surface hybrid stationary phase and the use of a column designed for carbohydrate separations. The method using anionic pairing reagent in the mobile phase was shown to be suitable for the quantitative determination of meglumine in solid dosage forms. The HPLC separation was achieved on an Agilent Eclipse XDB-C18 column (150 mm x 4.6 mm, 3.5 microm particle size) using a mobile phase with octane-1-sulfonic acid. The method was validated and validation included the following studies: selectivity, precision (repeatability), linearity and accuracy. During validation experiments RID and DAD detectors were used.     

Estimation of colchicine in a poisoned patient by using high performance liquid chromatography.

A rapid method was developed for the estimation of colchicine in plasma. The method was used to determine colchicine levels in a fatal case of colchicine self-poisoning.     

HPLC法测定复方制剂中醋酸氯己啶的含量

目的介绍一种在复方制剂中测定醋酸氯己啶含量的高效液相色谱法.方法采用C18柱和含十二烷基磺酸钠的甲醇/水流动相的高效液相色谱法.结果可获得优良的分离效果,对制剂中的醋酸氯己啶有高度性专一性,定量范围宽(1.0 ～76.9 mg·L-1),回收率良好(99.83%～100.31%),分析精度高(cev 0.15%),最低检测量(0.1 mg·L-1).结论此法可有效地用于产品质量控制,也可用于测定产品的稳定性.     

Measurement of serum lamotrigine by high performance liquid chromatography using a phenyltriazine as internal standard

Lamotrigine, an anti-epileptic drug with a phenyltriazine molecular structure, is commonly measured for therapeutic drug monitoring purposes by high performance liquid chromatography (HPLC) or gas liquid chromatography (GLC). A convenient internal standard is the structurally related phenyltriazine compound BWA725C previously obtainable from the Wellcome Foundation, UK. Irsogladine is also structurally similar to lamotrigine and was therefore tested as a possible replacement for BWA725C. A GLC procedure with thermionic detection (NPD) has been utilized routinely for lamotrigine in our drug monitoring facility. Irsogladine was unsuitable, however, because the retention times of irsogladine and a co-prescribed drug, carbamazepine, were very similar. An HPLC method utilizing a Prodigy Phenomenex ODS3 column performed well using either of the internal standards. The pH of the mobile phase had a distinct impact on the spectra of lamotrigine and BWA725C. A mobile phase at pH 3, with detection at 225 nm was required to effectively resolve lamotrigine from sulthiame and irsogladine from phenobarbitone. Comparison of the HPLC and the existing GLC method with routine patient specimens (n = 43) gave an equation, y = 0.9382x + 0.8238, R(2) = 0.9862. Irsogladine was found to be a suitable internal standard for an HPLC analysis of lamotrigine.     

Determination of pravastatin by high performance liquid chromatography

BACKGROUND: Pravastatin is a hydrophilic liver-specific inhibitor of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase. It effectively lowers plasma cholesterol and low-density lipoprotein concentrations in humans. Pharmacokinetic studies of pravastatin have been mostly performed by means of radioactively labelled drug or by measuring plasma concentrations with gas chromatography and mass spectrometry. AIMS OF THE STUDY: Aim of our study was to develop a simple, but reliable method which allows the determination of pravastatin plasma concentrations under clinical routine conditions. SUBJECTS, MATERIALS AND METHODS: Samples were prepared by solid-phase extraction on cyclohexyl bond elut cartridges. Chromatography was carried out on an octyl matrix. Triamcinolone acetonide was used as internal standard. The method was linear within the range of 5 to 200 microg/l pravastatin. The coefficient of variation depended on the pravastatin concentration, but was less than 10% throughout. The pharmacokinetics of pravastatin were determined in healthy individuals. Five healthy subjects received single oral doses of pravastatin (60 mg) and one of these subjects additionally received a dose of 80 mg at three different study days. In all subjects blood was sampled 0, 30, 60, 90, 120, 150, 180, 240 and 300 min after drug intake. RESULTS: Peak plasma concentrations of pravastatin were found between 60 min and 120 min after oral administration of 60 mg and reached values between 37 microg/l and 126 microg/l. The calculated AUCs were between 52 ng/ml x h and 311 ng/ml x h and the corresponding plasma elimination half-life times were between 95 min and 165 min. In all subjects plasma concentrations of pravastatin 5 hours after oral drug administration were near the detection limit of the method (5 microg/l). Intraindividually, there was only little variation in the kinetics of pravastatin. However, marked differences were encountered between the subjects studied. CONCLUSION: The data suggest that the determination of pravastatin plasma concentrations by means of a HPLC system can be used for routine analysis of pravastatin plasma concentrations. The obtained pharmacokinetic data in healthy individuals stand in ample agreement with the results of prior studies in which the concentrations of pravastatin were determined by other more sophisticated methods.     

HPLC梯度洗脱法测定对乙酰氨基酚原料药及有关物质对氨基酚

目的:采用高效液相色谱(HPLC)法测定对乙酰氨基酚原料药及有关物质的含量。方法:用ZORBAXSB-C18色谱柱(250mm×4.6mm,5μm),以5%乙腈的甲醇溶液和0.1%磷酸为流动相进行梯度洗脱,检测波长为272nm,流速1.0mL·min-1。结果:对乙酰氨基酚与对氨基酚能完全分离,对乙酰氨基酚和对氨基酚分别在10.64～106.4μg·mL-1和0.5104～5.104μg·mL-1浓度范围内峰面积与浓度呈良好的线性关系,相关系数分别为0.9999和0.9998,重复性试验的RSD为0.12%和8.6%。结论:该方法专属性好,操作简便,快速准确,可用于对乙酰氨基酚原料药及有关物质对氨基酚的含量测定。     

Simultaneous determination of serum flecainide and its metabolites by using high performance liquid chromatography

Simultaneous determination of serum flecainide and its oxidative metabolites was carried out by using high performance liquid chromatography (HPLC) equipped with conventional octadecylsilyl silica (ODS) column and fluorescence detector. Flecainide and its metabolites, m-O-dealkylated flecainide (MODF) and m-O-dealkylated lactam of flecainide (MODLF) in serum were extracted with ethyl acetate. The recoveries of flecainide, MODF and MODLF were greater than 92, 93, and 60% with the coefficient of variations (CVs) less than 3.2, 5.8, and 5.3%, respectively. The calibration curves were linear at the concentration range of 50–1500 ng/mL for flecainide and 10–500 ng/mL for MODF and MODLF (r>0.999). The CVs for intra-day assay were 2.7–5.3% for flecainide, 3.0–4.2% for MODF, and 3.7–4.3% for MODLF, respectively. The CVs for inter-day assay were 7.0–8.4% for flecainide, 3.3–6.7% for MODF, and 4.4–7.7% for MODLF, respectively. This assay method can be used for assessing the metabolic ability of flecainide in the patients with tachyarrhythmia.     

Analysis of 6-mercaptopurine in serum or plasma using high performance liquid chromatography

The analysis of 6-mercaptopurine (6-MP) by a rapid, sensitive, and specific high performance liquid chromatographic assay is described. This method does not require any derivatization and allows for direct quantitation of the drug. Only 200 microliters of serum or plasma is needed, and concentrations as low as 10 ng/ml can be reliably quantitated. Analytical recoveries of 83% for 6-MP and 71% for the internal standard, 6-thioguanine, are obtained. Between-day precision studies at three plasma concentrations of 6-MP produce a mean coefficient of variation of 7.2%. This assay will be clinically useful for pharmacokinetic studies of 6-MP in patients in remission of acute lymphoblastic leukemia.     

Determination of methazolamide concentrations in human biological fluids using high performance liquid chromatography

Methazolamide is a carbonic anhydrase inhibitor used to treat glaucoma. In vivo, methazolamide readily distributes into red blood cells. Therefore, both blood and plasma concentration data are needed in order to characterize the pharmacokinetics of methazolamide. In the present study, an analytical method using high performance liquid chromatography was validated for determination of methazolamide concentrations in several biological fluids. Through slight modification of a previously reported method for acetazolamide, another carbonic anhydrase inhibitor, methazolamide was readily quantitated in whole blood, plasma and urine. Sample preparation involved liquid–liquid extraction with ethyl acetate followed by a washing step using phosphate buffer (pH 8.0). After back extraction into glycine buffer (pH 10.0), samples were then washed with ether and injected onto the chromatograph. Chromatography was performed using a C-18, 5 μm reverse-phase column with UV detection at a wavelength of 285 nm. Mobile phase consisted of 0.05 M sodium acetate (pH 4.0) and acetonitrile (20%). The assay was validated over two standard concentration ranges from 1 to 100 μg ml⁻¹, concentrations reflective of those expected in vivo. Calibration curves were linear for all biological fluids and coefficients of variation for interday and intraday reproducibility studies were less than 8% (range 3.1–7.9%). The method was used to measure methazolamide concentrations in blood, plasma and urine following oral administration to five human subjects.     

Analysis of binary mixtures of losartan potassium and hydrochlorothiazide by using high performance liquid chromatography, ratio derivative spectrophotometric and compensation technique

A new simple, precise, rapid and selective reversed-phase high performance liquid chromatographic (HPLC) and two spectrophotometric methods have been described for resolving binary mixture of losartan potassium and hydrochlorothiazide in the pharmaceutical formulations. The first method, is based on HPLC on a reversed-phase column using a mobile phase 0.01 N sodium dihydrogen phosphate:methanol:acetonitrile (8:2:1 v/v/v) (pH 5.5) with detection at 265.0 nm. The second method, is depend on ratio derivative spectrophotometry, the amplitudes in the first derivative of the ratio spectra at 238.360 nm and at 230.423 nm were selected to simultaneously determine losartan potassium and hydrochlorothiazide in the mixture. The third method, based on compensation technique is presented for the derivative spectrophotometric determination of binary mixtures with overlapping spectra. By using ratios of the derivative maxima or the derivative minimum, the exact compensation of either component in the mixture can be achieved, followed by its determination. The accuracy and precision of the methods have been determined and they have been validated by analysing synthetic mixtures containing losartan potassium and hydrochlorothiazide. The methods do not require any separation step. The methods were also applied to the determination of losartan potassium and hydrochlorothiazide in pharmaceutical preparations. The analytical results were quite good in all cases.