Simple high-performance liquid chromatographic method for determination of ketoconazole in human plasma

A simple high-performance liquid chromatographic method using fluorescence detection was developed for the determination of ketoconazole in human plasma. The method entailed direct injection of the plasma sample after deproteinization using acetonitrile. The mobile phase comprised 0.05 M disodium hydrogen orthophosphate and acetonitrile (50:50, v/v) adjusted to pH 6. Analysis was run at a flow-rate of 1.5 ml/min with the detector operating at an excitation wavelength of 260 nm and an emission wavelength of 375 nm. The method is specific and sensitive with a quantification limit of approximately 60 ng/ml and a detection limit of 40 ng/ml at a signal-to-noise ratio of 3:1. Mean absolute recovery value was about 105%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 14%. The calibration curve was linear over a concentration range of 62.5–8000 ng/ml.     

顺式藁苯内酯口服给药在大鼠血浆和脑内的药动学特性(英文)

建立大鼠血浆和脑中Z-槀苯内酯(LIG)浓度测定的高效液相色谱法。采用Agilent Hypersil ODS C18色谱柱(150mm×4.6mm,5μm),流动相为甲醇-5%异丙醇水溶液(60:40,v/v),流速为1.0mL/min,检测波长为280nm。血浆与脑中槀苯内酯浓度线性检测范围分别为93.75~3750ng/m(r=0.9999)和93.75~3750ng/g(r=0.9997),日内及日间精密度RSD10%。本法适用于大鼠口服LIG后血浆及脑中药物浓度的研究。     

Determination of diazolidinyl urea in a topical cream by high-performance liquid chromatography

A high-performance liquid chromatographic method for the determination of diazolidinyl urea (DU) in a cream formulation is described. The aqueous phase of the emulsion was separated by centrifugation, removed, filtered, diluted and applied onto the HPLC system. DU was detected by ultraviolet absorption at a wavelength of 214 nm. The calibration curve was linear over the range of 79–553 μg/ml, and identical when determined on consecutive days. The relative standard deviation for repeat determinations was less than 0.5%. Recoveries were 97.74–101.72%. This analytical method is useful for quantitation of DU in cream formulations.     

Study on the interaction between nucleic acids and acetamiprid

The interaction between deoxyribonucleic acid (DNA) and acetamiprid was studied. It was found that the fluorescence of acetamiprid could be enhanced in the presence of DNA in sulfuric acid solution. The excitation and emission wavelength of acetamiprid was 291 nm and 587 nm, respectively. Under optimal conditions, the calibration graph is over the range of 0.1-10 micromL(-1). The calibration limit is 0.06 microg mL(-1) (S/N = 3). The determination results of DNA in yeast cell and golden staphylococcus samples by this method were satisfactory. The mechanism of the reaction is discussed.     

High-performance liquid chromatography spectrometric analysis of trans-resveratrol in rat plasma

A HPLC method for determination of trans-resveratrol concentrations in rat plasma was developed. Plasma samples were treated with acetonitrile to deposit proteins. The analysis used a Hypersil ODS(2) C(18) column (5 microm, 4.6 mm x 250 mm) and methanol/distilled water as the mobile phase (flow-rate=1 mL/min). The UV detection wavelength was 303 nm, and chlorzoxazone was used as the internal standard. The calibration curve was linear over the range of 0.02-40 microg/mL with a correlation coefficient of 0.9997. This concentration range corresponds well with the plasma concentrations of resveratrol in pharmacokinetic studies. There was 98.7%, 91.3% and 84.4% recovery from 0.02, 0.4 and 40 microg/mL plasma samples respectively. The R.S.D. of intra- and inter-day assay variations were all less than 12%. This HPLC assay is a quick, precise and reliable method for the analysis of resveratrol in pharmacokinetic studies.     

Measurement of bumetanide in plasma and urine by high-performance liquid chromatography and application to bumetanide disposition

A high-performance liquid chromatographic method for the measurement of bumetamide in plasma and urine is described. Following precipitation of proteins with acetonitrile, bumetanide was extracted from plasma or urine on a 1-ml bonded-phase C₁₈ column and eluted with acetonitrile. Piretanide dissolved in methanol was used as the internal standard. A C₁₈ Radial Pak column and fluorescence detection (excitation wavelength 228 nm; emission wavelength 418 nm) were used. The mobile phase consisted of methanol—water—glacial acetic acid (66:34:1, v/v) delivered isocratically at a flow-rate of 1.2 ml/min. The lower limit of detection for this method was 5 ng/ml using 0.2 ml of plasma or urine. Nafcillin, but not other semi-synthetic penicillins, was the only commonly used drug that interfered with this assay. No interference from endogenous compounds was detected. For plasma, the inter-assay coefficients of variation of the method were 7.6 and 4.4% for samples containing 10 and 250 ng/ml bumetanide, respectively. The inter-assay coefficients of variation for urine samples containing 10 and 2000 ng/ml were 8.1 and 5.7%, respectively. The calibration curve was linear over the range 5–2000 ng/ml.     

High-performance liquid chromatographic determination of tazobactam by precolumn derivatization

A new reversed-phase high-performance liquid chromatography (RP-HPLC) method for the detection and quantification of tazobactam in serum and haemofiltration fluid is described. The assay for these biological fluids involves an extraction with diethyl ether followed by derivatization using 1,2,4-triazole. The mobile phase consisted of phosphate buffer-methanol and the detection wavelength was 325 nm. The limit of detection was 0.05 μg/ml in the two fluids and the calibration curves were linear over the range 0.1–50 μg/ml. For a tazobactam concentration equal to 1, 5 or 20 μg ml⁻¹, the coefficients of variation were less than 5%. The assay was successfully applied to the analysis of samples from drug monitoring in a patient with renal insufficiency undergoing continuous venovenous haemofiltration (CVVH).     

Study on the Interaction Between Nucleic Acids and Imidacloprid and Its Application

The determination of imidacloprid with DNA via a resonance light scattering (RLS) technique was developed. The RLS of DNA was remarkably quenched after adding imidacloprid in aqueous medium of pH 2.10. An RLS peak at 311 nm was found, and the quenched intensity of RLS at this wavelength was proportional to the concentration of imidacloprid. The linear range of the calibration curve was approximately 0.02–2 μg/mL with the detection limit (S/N = 3) of 0.02 ng/mL. The imidacloprid in river water, cucumbers, and apple samples was determined. The recovery rates were in the range of 91.9% to 95.20%, 97.2% to 111.3%, and 94.5% to 114.8%, respectively. The mechanism of the reaction between imidacloprid and DNA is also discussed.     

Quantitative determination of epinastine in plasma by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method for the quantitative determination of epinastine, a non-sedating histamine H₁ receptor antagonist, in rat plasma, was developed. A 100-μl volume of plasma sample was spiked with a solution of internal standard (diphenidol) and extracted with dichloromethane under alkaline conditions. The extract was applied onto the HPLC system and detected by ultraviolet absorption at a wavelength of 220 nm. The linearity of the calibration curve was preserved over the concentration range of 20--1000 ng/ml. Both intra-assay variation and relative error were less than 5% for the plasma sample containing 50 ng/ml or 1000 ng/ml of epinastine hydrochloride. The analytical method presented here should be useful for the investigation of the pharmacokinetic properties of epinastine, which is of clinical significance.     

Simple high-performance liquid chromatographic method for the determination of ranitidine in human plasma

A simple high-performance liquid chromatographic method was developed for the determination of ranitidine in human plasma. Prior to analysis, ranitidine and the internal standard (metoprolol) were extracted from alkalinized plasma samples using dichloromethane. The mobile phase was 0.05 M potassium dihydrogenphosphate–acetonitrile (88:12, v/v) adjusted to pH 6.5. Analysis was run at a flow-rate of 1.3 ml/min and at a detection wavelength of 229 nm. The method is sensitive with a detection limit of 1 ng/ml at a signal-to-noise ratio of 3:1, while the quantification limit was set at 15 ng/ml. The calibration curve was linear over a concentration range of 15–2000 ng/ml. Mean recovery value of the extraction procedure was about 90%, while the within-day and between-day coefficients of variation and percent error values of the assay method were all less than 15%.     

An HPLC method for the pharmacokinetic study of daidzein-loaded nanoparticle formulations after injection to rats

This study was aimed at developing a simple HPLC method for the detection of daidzein in rat plasma. Daidzein was extracted from rat plasma with ethylparaben as internal standards (IS). Chromatographic separation of daidzein and IS was achieved by a Dikma Dimonsil C18 column (200 mm × 4.6mm) with the mobile phase consisting of methanol-water (55:45, v/v) at a flow rate of 1.0 mL/min. The injection volume was 20 μL and the detecting wavelength was 249 nm. The calibration curve was linear over a concentration range from 0.05 to 5 μg/mL, and the accuracy was within a range of 93.4-126.2%. This HPLC method was applied successfully to the pharmacokinetic study of two kinds of daidzein-loaded poly(lactide-co-glycolide) (PLGA) nanoparticles (D-NPs) and daidzein suspension after intravenous injection in rats. Significant differences in main pharmacokinetic parameters of daidzein suspension and D-NPs were observed.     

Simple high-performance liquid chromatographic method for the determination of metformin in human plasma

A simple high-performance liquid chromatographic method using ultraviolet detection was developed for the determination of metformin in human plasma. The method entailed direct injection of the plasma sample after deproteination using perchloric acid. The mobile phase comprised 0.01 M potassium dihydrogen orthophosphate (pH 3.5) and acetonitrile (60:40, v/v). Analyses were run at a flow-rate of 1.0 ml/min with the detector operating at a detection wavelength of 234 nm. The method is specific and sensitive, with a quantification limit of approximately 60 ng/ml and a detection limit of 15 ng/ml at a signal-to-noise ratio of 3:1. The mean absolute recovery value was about 97%, while the within-day and between-day coefficient of variation and percent error values of the assay method were all less than 8%. The calibration curve was linear over a concentration range of 62.5–4000 ng/ml.     

Determination of ketamine and norketamine enantiomers in plasma by solid-phase extraction and high-performance liquid chromatography

A high-performance liquid chromatographic method is described for determination of sub-anaesthetic concentrations of the enantiomers of ketamine and its metabolite norketamine in plasma. The samples are purified by reversed-phase solid-phase extraction. The enantiomers are separated on a Chiral AGP column with a mobile phase containing 16% methanol and a 10 mM phosphate buffer at pH 7.0, and measured by UV-detection at a wavelength of 220 nm. Linear calibration curves with correlation coefficients better than 0.995 have been obtained in the range 10–320 ng/ml. Minimum detectable concentrations were about 2 ng/ml.     

梯度洗脱高效液相色谱法测定桑叶中3种活性成分的含量

建立同时测定桑叶中绿原酸、芦丁和槲皮素含量的分析方法。色谱柱为NUCLEODUR C18 RP(250 mm×4.6 mm,5μm),光电二极管检测器,流动相为甲醇-质量分数0.5%磷酸水溶液,梯度洗脱程序为0 min(30:70)-15min(30:70)-25min(50:50)-35min(85:15)-40min(30:70);流速0.8 ml.min-1,检测波长为350 nm。绿原酸、芦丁和槲皮素的线性范围分别为0.1144~1.0296μg(r=0.9996)、0.0436~0.3924μg(r=0.9999)和0.0452~0.4068μg(r=0.9997),平均回收率分别为97.7%(RSD=1.7%)、98.4%(RSD=2.2%)和100.6%(RSD=1.5%)。方法快速简便,专属性强,重复性好,可作为桑叶中绿原酸、芦丁和槲皮素的定量分析方法。     

Study on the Interaction Between Nucleic Acids and Acetamiprid

Abstract

The interaction between deoxyribonucleic acid (DNA) and acetamiprid was studied. It was found that the fluorescence of acetamiprid could be enhanced in the presence of DNA in sulfuric acid solution. The excitation and emission wavelength of acetamiprid was 291 nm and 587 nm, respectively. Under optimal conditions, the calibration graph is over the range of 0.1–10 µg mL^?1. The calibration limit is 0.06 µg mL^?1 (S/N = 3). The determination results of DNA in yeast cell and golden staphylococcus samples by this method were satisfactory. The mechanism of the reaction is discussed.     

拳卷地钱中黄酮类化合物的含量测定

本文建立了拳卷地钱中黄酮类化合物的含量测定方法。采用改进的铝盐显色分光光度法测定拳卷地钱总黄酮含量;采用反相高效液相色谱法测定拳卷地钱黄酮类化合物中芹菜素、槲皮素和木犀草素的含量。分光光度法表明：总黄酮含量在1．6～16μg/mL范围内,线性关系良好,加标回收率在97．61～101．59％,相对标准偏差0．16％;反相高效液相色谱法表明平均加标回收率96．79～101．13％,相对标准偏差0．66～1．52％。本方法用于拳卷地钱中黄酮类化合物含量的测定准确可靠,结果令人满意。     

Affinity partitioning of glucose-6-phosphate dehydrogenase and hexokinase in aqueous two-phase systems with free triazine dye ligands

We have established a robust, fully automated analytical method for the determination of indomethacin in rat plasma using a column-switching high-performance chromatographic system. The system consists of a precolumn and an analytical column connected in series via a switching valve. When a 50-microl portion of rat plasma containing a therapeutic level of indomethacin was applied directly to the system, the drug was automatically enriched in the precolumn (TSK BSA-ODS) by on-line solid-phase extraction. After elution of the plasma proteins, the analyte was automatically transferred to the analytical column (Zorbax Eclipse XDBC18) where chromatography was performed using isocratic elution and UV absorption detection at a wavelength of 254 nm. The separation mobile phase consisted of methanol-0.1% phosphoric acid (70:30, v/v) at a flow-rate of 1 ml/min. The calibration line for indomethacin showed good linearity in the range 50-10 000 ng/ml (r>0.999) with the detection quantification of 50 ng/ml (RSD=2.6%). Accuracy ranged from -0.62 to 3.22%, and the within- and between-day precision of the assay was better than 6% across the calibration range. The analytical sensitivity and accuracy of this assay is suitable for characterization of the pharmacokinetics of topical administration of imdomethacin to rats. The method has been successfully used to provide pharmacokinetic data in a large number of diverse pharmaceutical studies.     

Measurement of epidoxorubicin and its metabolites by high-performance liquid chromatography using an advanced automated sample processor

A sensitive and rapid method for measuring epidoxorubicin and its six metabolites by high-performance liquid chromatography using an advanced automated sample processor is described. Plasma samples (1 ml) were extracted using C₂ cassettes, and reversed-phase chromatography was performed with an Apex II ODS column. The isocratic mobile phase of acetonitrile—0.019 M NaH₂PO₄ (pH 4.0) had a flow-rate of 1 ml/min and the fluorescence detector an excitation wavelength of 480 nm with an emission at 580 nm. Linear calibration curves were obtained which were reproducible both within-day and day-to-day (coefficients of variation < 10%). The extraction efficacy of epidoxorubicin was 88% and ranged from 51 to 88% for the metabolites. This method has been successfully applied to measure the plasma levels of these compounds in patients receiving epidoxorubicin over a wide dose range (12–120 mg/m²) and in patients with disturbed liver biochemistry.     

Quantitation of ibogaine and 12-hydroxyibogamine in human plasma by liquid chromatography with fluorimetric detection

A high-performance liquid chromatographic (HPLC) method with fluorimetric detection was developed for the simultaneous determination of ibogaine and noribogaine in human plasma using fluorescein as internal standard. This method involved a solid phase extraction of the compounds from plasma using N-vinylpyrrolidone-divinybenzene copolymer cartridges. Separation of the three analytes was performed on a reversed-phase Supelcosil C18 analytical column (75 mm x 4.6mm i.d., 3 microm particle size). The excitation wavelength was set at 230 nm for the first 15.8min and then at 440 nm for the following 14.2 min; the emission wavelength was set at 336 nm for the first 15.8 min and then at 514 nm for the following 14.2 min. Obtained from the method validation, inter-assay precision was 6.0-12.5% and accuracy was 95.4-104%. The extraction efficiencies of the assay were higher than 94% and were constant across the calibration range. The lower limits of quantitation were 0.89 ng/ml for ibogaine and 1 ng/ml for noribogaine; at these levels, precision was < or =17% and accuracy was 95-105%. In this paper, extensive stability testing was undertaken using a wide range of storage conditions. Special attention must be paid to sample handling to avoid light degradation of the compounds.     

Turbidimetric method for quantitative determination of triton X-100 with silicotungstic acid

The Formation of Triton X-100-silicotungstic acid complex was studied. Quantitative turbidimetric determination of the detergent based on this process was suggested. This method allows to determining the complex formation at any wavelength in the range from 350 (epsilon 350 = 15,600 cm-1 M-1) to 600 nm (epsilon 600 = = 9090 cm-1 M-1). The calibration curve for Triton X-100 recorded at 350 nm is linear in the concentration range of 0 to 30 micrograms/ml. A sigmoid calibration curve was observed at longer wavelengths. A linear fragment of the calibration curve recorded at 600 nm was found at a concentration of Triton X-100 of about 5 micrograms/ml. The complex nature of calibration curves can be explained by heterogeneity of the complex dispersion.