Determination of tapentadol and its metabolite N-desmethyltapentadol in urine and oral fluid using liquid chromatography with tandem mass spectral detection

An analytical procedure for the determination of the new pain medication tapentadol and its main metabolite N-desmethyltapentadol (DMT), in urine and oral fluid has been developed and validated using liquid chromatography with tandem mass spectral detection (LC-MS-MS). Oral fluid was collected using Quantisal? devices, and drugs present were quantified using solid-phase extraction followed by LC-MS-MS. For confirmation, two transitions were monitored and one ratio determined which had to be within 20% of that of the known calibration standard. For tapentadol, 222.1 > 107 was used as the quantifying transition; 222.1 > 121 for the qualifier. For DMT, 208.1 > 107 was used for quantification; 208.1 > 121 as the qualifier. For saliva, the linear range was 10-100 ng/mL; the lower limit of quantitation (LLOQ) was 10 ng/mL; the intraday precision was 3.6% (n = 6) and interday precision was 13.6% (n = 24). The recovery of tapentadol and DMT from the oral fluid collection pad was > 99%. For urine, the specimens were diluted and injected directly into the LC-MS-MS. The LLOQ was 50 ng/mL; the intraday and interday precisions were 2.1% and 4.4%, respectively, for tapentadol and 2.9% and 5.7%, respectively, for DMT. This is the first analytical procedure for tapentadol and DMT in urine and oral fluid.     

Quantitative analysis of the immunosuppressant CP-690,550 in whole blood by column-switching high-performance liquid chromatography and mass spectrometry detection

A fast and accurate method to quantify the new immunosuppressive JAK3 inhibitor CP-690,550 in whole blood using a dual-pump liquid chromatography-liquid chromatography-mass spectrometry (LC/LC-MS) system was developed and validated in nonhuman primate blood. Before injection, blood samples were prepared by precipitation with a reagent that included methanol and acetonitrile (30:70, vol/vol) along with the internal standard (CP-istd). Column-switching LC/LC-MS analysis used online extraction followed by separation on a C8 analytic column and MS detection of the [M + H] CP-690,550 (m/z = 313.1) and CP internal standard (m/z = 288.1). Linearity was always better than r = 0.99 (n = 7) for CP-690,550 (range 2.5-750 ng/mL), with a lower limit of quantification (LLOQ) of 2.5 ng/mL. The intrarun accuracy and precision ranged from 103.0% to 105.4% and 2.7% to 4.3%, respectively (n = 5), and the interday precision ranged from 8.7% to 11.1%, and the interday accuracy ranged from 98.1% to 103.8% of nominal values (n = 14). The injection repeatability for the method was 1.3% (n = 7). Except for the LLOQ, the intraday accuracy and precision in human blood were also within 15% (n = 5). The combination of simple sample preparation and short analytic run time of this sensitive procedure makes it effective for monitoring the concentration of CP-690,550 in whole blood in organ-transplant recipients.     

Validation of an automated liquid chromatographic method for omeprazole in human plasma using on-line solid-phase extraction

An automated system using on-line solid-phase extraction and HPLC with UV detection has been validated in order to determine omeprazole in human plasma. The extraction was carried out using C18 cartridges. After washing, omeprazole was eluted from the cartridge with mobile phase onto an Inertsil ODS-2 column. The developed method was selective and linear for drug concentrations ranging between 5 and 500 ng ml(-1). The recovery of omeprazole ranged from 88.1 to 101.5%, and the limit of quantitation (LOQ) was 5 ng ml(-1). The intraday accuracy ranged from 93.1 to 106.2% and the interday accuracy varied from 95.4 to 105.1%. For the LOQ, good values of precision (8.7 and 17.5% for intraday and interday, respectively) were also obtained. This automated system has been applied to determine omeprazole in human plasma samples from bioequivalence studies.     

Validation of a headspace GC method for the analysis of a pyrolytic product of methamphetamine in urine

A method has been developed and validated using headspace GC-FID for the identification of 1-phenylpropene in urine. This compound is a pyrolytic product of methamphetamine that has been previously proposed as a marker for smoked methamphetamine. The instrumentation used is the same as employed for blood alcohol determination. The extraction-free procedure is rapid, simple, and quantitative using 2-phenylpropene as the internal standard. The method was validated for linearity over a range of 0.1-20 microg/mL with a limit of detection of 0.05 microg/mL, limit of quantification of 0.1 microg/mL, interday accuracy within 3.2 to -5.3%, intraday accuracy better than 7.5%, interday precision of 7.5 to 10.7%, intraday precision of 2 to 8.6%, and recovery above 80%. For the robustness determination in urine, the accuracy of four different sources of urine at the mid control level (1 microg/mL) ranged from 1.6 to 19% error. The % relative standard deviation of the different urine sources ranged from 3.1 to 11%. Urine samples from nine methamphetamine-positive cases investigated by the Office of the Chief Medical Examiner of West Virginia were included in the study. 1-Phenylpropene was found in two methamphetamine-positive cases (0.25 and 0.44 microg/mL).     

Potential marker for smoked methamphetamine hydrochloride based on a gas chromatography-mass spectrometry quantification method for trans-phenylpropene

Residue from smoked methamphetamine hydrochloride contains pyrolytic products that are detectable by gas chromatography-mass spectrometry (GC-MS). A validated GC-MS method was developed for the determination of trans-phenylpropene, a pyrolytic product of methamphetamine HCl, in residue of smoked drug as well as in human urine. trans-Phenylpropene and an isomeric internal standard, 2-phenylpropene, were extracted from urine using n-hexane. The method was validated for linearity over a range of 0.1-10 microg/mL with a limit of detection of 0.05 microg/mL, limit of quantification of 0.1 microg/mL, interday accuracy within 10.5%, intraday accuracy better than 3.7%, interday precision of 15.4%, intraday precision of 14.4%, and recovery of 89.1%. The method was applied to the detection of trans-phenylpropene found in the residue of methamphetamine HCl heated beyond its melting temperature on aluminum foil under simulated smoking conditions. The method is applicable to the detection of trans-phenylpropene in urine as a potential marker for smoked methamphetamine HCl abuse.     

An expedient assay for determination of gemcitabine and its metabolite in human plasma using isocratic ion-pair reversed-phase high-performance liquid chromatography

An expedient method is presented for determination in human plasma of gemcitabine and its metabolite 2',2'-difluorodeoxyuridine (dFdU) by ion-pair reversed-phase HPLC. Samples were simply prepared by protein precipitation. Separation was processed on a Thermo Hypersil column (250 x 4.6 mm, 5 microm Hypersil BDS C18) with UV detection at 272 nm. The mobile phase consisted of 17% methanol and 83% phosphate buffer (20 mM, pH 3.1) containing 10 mM sodium 1-heptanesulfonate with a flow rate of 0.8 mL/min. The lower limit of quantification (LLOQ) of gemcitabine was 0.08 microg/mL with linear response over the range 0.08-20.0 microg/mL, and LLOQ of dFdU was 0.1 microg/mL with linear response over the range 0.1-50.0 microg/mL. Assay accuracy for both compounds was within +/- 4%. The coefficient of variation (CV %) for intra- and interday precision for both compounds was <7%. The correlation coefficients (r2) were greater than 0.9996 for all standard curves. The simple method with adequate sensitivity has been successfully used in phase I and II gemcitabine pharmacokinetic and pharmacodynamic studies in an Asian population.     

Quantitative analysis of oxytetracycline and its impurities by LC-MS-MS

A liquid chromatographic-tandem mass spectrometric method using an Xterra MS C(18) chromatographic column ( 100 mm x 2.1 mm i.d., 3.5microm) that allows complete separation of oxytetracycline (OTC) and the impurities: 4-epi-oxytetracycline (EOTC), tetracycline (TC), 4-epi-tetracycline (ETC), 2-acetyl-2-decarboxamido-oxytetracycline (ADOTC), alpha-apo-oxytetracycline (alpha-AOTC) and beta-apo-oxytetracycline (beta-AOTC) was developed. Gradient elution was used and calibration curves were obtained using the scan mode selected reaction monitoring (SRM). Acceptable correlations were obtained for OTC, TC, EOTC and ADOTC whereas the correlations of alpha-AOTC and beta-AOTC were less accurate resulting in higher limits of quantification (LOQ) and limits of detection (LOD) relative to the other compounds. The intraday and interday accuracy varied for all the compounds from 90 to 112% and the intraday and interday precision were lower than 7.1%. The method was applied for analysis of commercial available ointments containing OTC resulting in an acceptable quantification of OTC and the impurities in the drug preparations. The advantage of this method compared to the other separation methods is an empty separation window right after the large peak corresponding to OTC in the chromatogram, which facilitates an accurate determination of ADOTC and the other impurities.     

Determination of nimodipine in human plasma by ultra performance liquid chromatography-tandem mass spectrometry and pharmacokinetic application

A fast and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination and pharmacokinetic study of nimodipine in human plasma. With nitrendipine as the internal standard, sample pretreatment involved one-step extraction with diethyl ether of 0.5 ml plasma. The separation was carried out on an ACQUITY UPLC BEH C(18) column (50 mm x 2.1 mm, i.d., 1.7 microm) with water and acetonitrile (both containing 0.1% formic acid) as the mobile phase under gradient conditions at a flow rate of 0.35 ml/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source. The standard curves were linear (r(2)> or =0.99) over the concentration range of 0.20-100 ng/ml with a limit of quantification (LLOQ) of 0.20 ng/ml. The intra- and inter-day precision (R.S.D.) values were below 14% and the accuracy (relative error R.E.) was ranged from -2.2% to 7.7% at all three quality control (QC) levels. The method herein described was superior to previous methods and successfully applied to the pharmacokinetic study of nimodipine tablets in healthy male volunteers after oral administration.     

A stability-indicating HPLC assay for metronidazole benzoate

A simple and rapid stability-indicating HPLC assay procedure has been developed and validated for metronidazole benzoate. The HPLC conditions were as follows, column: Waters Symmetry C8, 5 microm packing, 4.6 mm x 250 mm; detection: UV at 271 nm; injection volume: 20 microl; mobile phase: acetonitrile-0.1% glacial acetic acid in monobasic potassium phosphate (0.01 M) (40:60, v/v); isocratic elution under ambient temperature at 2.0 ml min(-1). The procedure separated metronidazole benzoate and its potential degradation products, metronidazole and benzoic acid, in an overall analysis time of about 6 min with metronidazole benzoate eluting at about 5 min. The injection repeatability was 0.03%, and the intraday and interday repeatability were 0.4 and 0.7%, respectively. The procedure provided a linear response over the concentration range 0.2-800 microg ml(-1) (r=1.0000) with the limits of detection and quantitation 0.03 and 0.2 microg ml(-1), respectively. The solubilities of metronidazole benzoate in water, 0.01 M hydrochloric acid and 0.05 M phosphate buffer, pH 6.8, determined each in triplicate using the procedure, were 0.2 mg ml(-1) (R.S.D. 7%), 0.4 mg ml(-1) (R.S.D. 2%) and 0.2 mg ml(-1) (R.S.D. 8%), respectively. The results show no detectable hydrolysis of metronidazole benzoate in 0.01 M hydrochloric acid at 37 degrees C or in the mobile phase at ambient temperature in 10 h.     

Determination and pharmacokinetics of isoferulic acid in rat plasma by high-performance liquid chromatography after oral administration of isoferulic acid and Rhizoma Cimicifugae extract

A simple and specific high-performance liquid chromatographic (HPLC) method with ultraviolet (UV) absorbance detection has been developed for the determination of isoferulic acid in rat plasma. The plasma samples were deproteinized with methanol after the addition of internal standard (IS) tinidazole. The analysis was performed on a Kromasil C18 column (250 mm x 4.6 mm i.d., 5 microm particle size) with acetonitrile-0.05% phosphoric acid (25:75, v/v) as mobile phase. The linear range was 0.0206-5.15 microg ml(-1) and the lower limit of quantification (LLOQ) was 0.0206 microg ml(-1). The intra- and inter-day relative standard deviations (R.S.D.s%) were less than 11.4 and 12.3%, respectively, and accuracy as relative error (R.E.%) between -6.7 and -1.1%. Mean extraction recovery was above 80%. The validated method was successfully applied to the pharmacokinetic study of isoferulic acid in rat plasma after oral administration of isoferulic acid and Rhizoma Cimicifugae extract.     

Development and validation of ELISA and GC-MS procedures for the quantification of dextromethorphan and its main metabolite dextrorphan in urine and oral fluid

The development of a highly sensitive enzyme-linked immunosorbent assay and gas chromatography-mass spectrometry confirmation method for the detection of dextromethorphan and its major metabolite dextrorphan in urine and oral fluid is described. For the screening assay, the intraday precision was less than 8% for urine and less than 5% for oral fluid. The interday precision was less than 10% for both drugs in urine and oral fluid. For the confirmatory procedure, both inter- and intraday precision was less than 5% for both matrices. The detection limit for both methods was 1 ng/mL. The quantifying ions chosen from the full scan mass spectra were m/z 271 for dextromethorphan, m/z 329 for dextrorphan, and m/z 332 for tri-deuterated dextrorphan-d(3). A high recovery yield (> 93%) from the Quantisal oral fluid collection device was achieved, and the drugs were stable in the collection device for at least 10 days at room temperature. The extracted drugs from both matrices were stable for at least 48 h while kept at room temperature. Both screening and confirmatory procedures were applied to authentic urine and oral fluid specimens obtained from volunteers following therapeutic ingestion of dextromethorphan.     

A sensitive LC/MS/MS method using silica column and aqueous-organic mobile phase for the analysis of loratadine and descarboethoxy-loratadine in human plasma

A sensitive method using liquid chromatography with tandem mass spectrometric detection (LC/MS/MS) was developed and validated for the simultaneous analysis of antihistamine drug loratadine (LOR) and its active metabolite descarboethoxy-loratadine (DCL) in human plasma. Deuterated analytes, i.e. LOR-d(3) and DCL-d(3) were used as the internal standards (I.S.). Analytes were extracted from alkalized human plasma by liquid/liquid extraction using hexane. The extract was evaporated to dryness under nitrogen, reconstituted with 0.1% (v/v) of trifluoroacetic acid (TFA) in acetonitrile, and injected onto a 50 x 3.0 mm I.D. 5 microm, silica column with an aqueous-organic mobile phase consisted of acetonitrile, water, and TFA (90:10:0.1, v/v/v). The chromatographic run time was 3.0 min per injection and flow rate was 0.5 ml/min. The retention time was 1.2 and 2.0 min for LOR and DCL, respectively. The tandem mass spectrometric detection was by monitoring singly charged precursor-->product ion transitions: 383-->337 (m/z) for LOR, 311-->259 (m/z) for DCL, 388-->342 (m/z) for LOR-d(3), and 316-->262 (m/z) for DCL-d(3). The low limit of quantitation (LLOQ) was 10 pg/ml for LOR and 25 pg/ml for DCL. The inter-day precision of the quality control (QC) samples was 3.5-9.4% relative standard deviation (R.S.D.). The inter-day accuracy of the QC samples was 99.0-107.9% of the nominal values.     

Quantification of sofalcone in human plasma and urine by high performance liquid chromatography-mass spectrometry

Sofalcone, isolated from the root of the Chinese medicinal plant Sophora subprostrata, is well known to be a mucosal protective agent for gastritis and peptic ulcer treatment. Although the LC-MS/MS and HPLC-DAD methods for assay of plasma concentration of sofalcone were reported before for the pharmacokinetic study, they were either too complicated or not sensitive enough for current pharmacokinetic study. In addition, no urinary assay method or pharmacokinetic information was available. Thus an improved high performance liquid chromatography-mass spectrometric method employing negative electrospray ionization was developed for the determination of sofalcone concentration in human plasma and urine sample. A liquid-liquid extraction method was utilized to extract sofalcone together with the indometacin (internal standards) from 0.5ml of human plasma or urine samples. Multiple reaction monitoring was used for quantification by monitoring the transition of m/z from 449.5 to 313.1 for sofalcone and 356.9 to 313.0 for IS. The validation of the method regarding to specificity, sensitivity, linearity, reproducibility, accuracy and stability was evaluated. The lower limit of quantification (LLOQ) of the developed assay method for sofalcone was 0.5ng/ml and the linear calibration curve was acquired with R(2)>0.99 between 0.5 and 500ng/ml for both plasma and urine samples. The intra- and inter-day variations of the current assay were evaluated with the relative standard deviation (RSD) within 13.77% at low concentration of quality control samples (QCs) and 8.71% for other QCs, whereas the mean accuracy ranged from 96.21 to 107.33%. The samples were found to be stable under the storage conditions at least for a month and other experimental conditions. This validated method was then utilized to test sofalcone concentration in clinical samples. Based on these data, the pharmacokinetic behavior of sofalcone in plasma as well as urine was described. As a conclusion, the present method proved to be a rapid and sensitive analytical tool for sofalcone in human plasma or urine samples and has been successfully applied to a clinical pharmacokinetic study of in healthy Chinese subjects.     

LC-MS/MS法分析人血浆中西格列汀浓度及其应用研究

摘要：目的 建立一种测定人血浆中西格列汀浓度的液相色谱-串联质谱（LC-MS/MS）分析方法,并将该方法应 用于西格列汀在人体内的药代动力学研究。方法 以西格列汀-d4为内标,血浆样品经CleanertPPT沉淀板沉淀后, 通过Diamonsil C18色谱柱（100 mm×4.6 mm,5 μm）进行分离,使用甲醇-10 mmol/L甲酸铵水溶液（含10%甲醇,0.1% 甲酸）作为流动相,进行梯度洗脱,流速为0.5 mL/min。通过电喷雾电离源（ESI）,以多反应监测（MRM）模式进行正离 子检测。从选择性、残留、线性范围与定量下限、精密度与准确度、基质效应和回收率、稳定性方面进行方法学验证。 同时考察健康人口服西格列汀片100 mg后的主要药代动力学参数。结果 西格列汀、西格列汀-d4的MRM离子对 分别为 m/z 408.0→235.2、m/z 412.1→239.0。人血浆中西格列汀在 0.5～1 000 μg/L 浓度范围内线性关系良好（R2> 0.99）,定量下限为0.5 μg/L;定量下限和质控样品的批内、批间精密度（RSD）在0.83%~12.80%之间,准确度（RE）在± 10.0%以内。健康人口服西格列汀片100 mg后主要药代动力学参数：达峰时间（Tmax）、达峰浓度（Cmax）、、生物利用度 （AUC）、半衰期（T1/2）分别为（2.44±1.29）h、（375±138）μg/L、（2 915±585）h·μg/L、（11.10±2.41）h。结论 本LC-MS/ MS分析方法敏感度高且样品处理方法简单快速,满足生物分析的法规要求,可应用于人体内西格列汀的药代动力学 研究。     

Simultaneous determination of rosuvastatin and fenofibric acid in human plasma by LC-MS/MS with electrospray ionization: assay development, validation and application to a clinical study

A simple, sensitive and specific LC-MS/MS method for simultaneous determination of rosuvastatin (RST) and fenofibric acid (FFA) was developed and validated with 500 microL human plasma using carbamazepine as an internal standard (IS). The assay procedure involved a simple one-step liquid/liquid extraction of RST and FFA and IS from plasma into ethyl acetate. The organic layer was separated and evaporated under a gentle stream of nitrogen at 40 degrees C. The residue was reconstituted in the mobile phase and injected onto X-Terra MS C-18 column (4.6 mm x 50 mm, 5.0 microm). Separation of RST, FFA and IS was achieved with a mobile phase consisting of 0.05 M formic acid:acetonitrile (45:55, v/v) at a flow rate of 0.40 ml/min. The API-3000LC-MS/MS was operated under the multiple reaction-monitoring mode (MRM) using the electrospray ionization technique. Positive ion acquisition chromatographic run was used in the present method. Nominal retention times of RST, FFA and IS were 2.35, 4.70 and 2.32 min, respectively. Absolute recovery of RST, FFA and IS was 74, 61 and 69%, respectively. The lower limit of quantification (LLOQ) of RST and FFA was 1.00 ng/ml and 0.50 microg/ml, respectively. Response function was established for the range of concentrations 1.00-50.0 ng/ml and 0.50-20.0 microg/ml for RST and FFA, respectively, with a coefficient of determination (r2) of 0.999 for both the compounds. The inter- and intra-day precision in the measurement of RST quality control (QC) samples 5, 15, 400 and 800 ng/ml, were in the range 8.93-9.37% relative standard deviation (R.S.D.) and 1.74-16.1% R.S.D., respectively. Similarly, the inter- and intra-day precision in the measurement of FFA quality control (QC) samples 0.5, 1.5, 8.0 and 15.0 microg/ml, were in the range 9.78-11.6% relative standard deviation (R.S.D.) and 0.22-17.4% R.S.D., respectively. Accuracy in the measurement of QC samples for RST and FFA were in the range 88.1-108 and 87-115%, respectively, of the nominal values. RST and FFA were stable in the battery of stability studies, viz., bench-top, auto-sampler and freeze/thaw cycles. Stability of RST and FFA was established for 1 month at -80 degrees C. The application of the assay to a clinical study confirmed the utility of the assay.     

High-performance liquid chromatography-electrospray ionization mass spectrometry determination of sodium ferulate in human plasma

A selective and sensitive high-performance liquid chromatography-electrospray ionization mass spectrometry method has been developed for the determination of sodium ferulate in human plasma. The sample preparation was a liquid-liquid extraction and chromatographic separation was achieved with an Agilent ZORBAX SB-C(18) (3.5 microm, 100 mm x 3.0 mm) column, using a mobile phase of methanol-0.05% acetic acid 40:60 (v/v). Standard curves were linear (r(2)=0.9982) over the concentration range of 0.007-4.63 nM/ml and had acceptable accuracy and precision. The within- and between-batch precisions were within 12% relative standard deviation. The lower limit of quantification (LLOQ) was 0.007 nM/ml. The validated HPLC-ESI-MS method has been used successfully to study sodium ferulate pharmacokinetics, bioavailability and bioequivalence in 20 healthy volunteers.     

Development and Validation of a HPLC Method for the Determination of Cyclosporine A in New Bioadhesive Nanoparticles for Oral Administration

A simple and reliable high performance liquid chromatography method was developed and validated for the rapid determination of cyclosporine A in new pharmaceutical dosage forms based on the use of poly (methylvinylether-co-maleic anhydride) nanoparticles. The chromatographic separation was achieved using Ultrabase C₁₈ column (250×4.6 mm, 5 μm), which was kept at 75°. The gradient mobile phase consisted of acetonitrile and water with a flow rate of 1 ml/min. The effluent was monitored at 205 nm using diode array detector. The method exhibited linearity over the assayed concentration range (22-250 μg/ml) and demonstrated good intraday and interday precision and accuracy (relative standard deviations were less than 6.5% and the deviation from theoretical values is below 5.5%). The detection limit was 1.36 μg/ml. This method was also applied for quantitative analysis of cyclosporine A released from poly (methylvinylether-co-maleic anhydride) nanoparticles.     

Conventional and micellar liquid chromatography method development for danazol and validation in capsules

Two isocratic liquid chromatographic methods (conventional and micellar) for the determination of danazol (DZ) in capsules using canrenone (CAN) as internal standard have been developed and validated. In conventional liquid chromatography a mobile phase 35% water:acetonitrile 65%, v:v, a flow-rate 1 ml min(-1) and a C18 Hypersil ODS (250 x 4.6 mm, 5 microm) column (25 degrees C) were used. In micellar liquid chromatography (MLC) the conditions were: mobile phase 40 mM sodium dodecyl sulfate:2% pentanol, flow-rate 0.5 ml min(-1) and C18 Hypersil ODS (150 x 3.0 mm, 5 microm) column (60 degrees C). For both methods. UV absorbance detection at 280 nm was used and a separation up to base line was achieved. Prior to HPLC analysis a simple sample preparation was required. The recoveries found in the accuracy test were 99 +/- 10 and 101 +/- 8%, in conventional liquid chromatography (CLC) and MLC, respectively. Repeatability and intermediate precision expressed as R.S.D. were lower than 5% for both methods. Detection limits obtained were 2.4 and 3.0 ng g(-1) in CLC and CLM, respectively.     

Determination of cyanocobalamin, betamethasone, and diclofenac sodium in pharmaceutical formulations, by high performance liquid chromatography

The aim of this work was to develop an analytical method for a simultaneous determination of cyanocobalamin (Vitamin B12), betamethasone, and diclofenac, present in pharmaceutical formulations, by high performance liquid chromatography, assuring rapidity, accuracy, precision, and selectivity. The working conditions were as follows: RP18 column of 125 mm x 4 mm ID and a particle size of 5 microm; mobile phase acetonitrile-water (40:60; v/v) (pH* 3.45) adjusted with acetic acidl flow gradient from 0.8 to 1.9 ml/min.; injection volume of 20 microl; temperature 34 degrees C and detection at 240 nm. The method was adequately validated, and linearity, accuracy, as well as the system, method and interday precision, for each active principle, were determined.     

RP-HPLC法研究白藜芦醇衍生物(BTM-0512) 在大鼠血浆与组织中的分布

建立大鼠血浆与组织中白藜芦醇衍生物(BTM-0512)高效液相色谱测定方法,用于研究BTM-0512在大鼠体内的分布。色谱柱：BDS Hypersil C₁₈(250 mm×4.6 mm ID，5 μm)，流动相：乙腈-水(55∶45)，流速：1 mL·min^-1，检测波长：319 nm，己烯雌酚作内标。含药血浆与组织匀浆液用乙腈直接沉淀蛋白后，进样分析。本法线性范围为血浆：0.01～10.0 μg·mL^-1，组织样品：0.04～40 μg·g^-1，r²均大于0.996(n=7),方法的准确度平均值在95.3%～100.1%；提取回收率在95.9%～100.9%；日内、日间RSD<5.1%。BTM-0512在血浆中含量较低，在肝脏中分布最多，在脂肪中有蓄积现象。本法灵敏度高，操作简便、准确，可用于大鼠血浆及组织中BTM-0512的测定及分布研究。