高效液相色谱-串联质谱法测定血浆中黄豆苷元的浓度

目的:建立高效液相色谱-串联质谱联用(LC-MS-MS)的方法测定人血浆内黄豆苷元的浓度,并应用于药动学研究和生物等效性评价。方法:以木犀草素为内标,甲醇(含0．2%乙酸)为蛋白沉淀剂,采用Merck LiChroCART C_(18)色谱柱分离,通过LC-MS-MS电喷雾离子源(ESI),以选择反应监测(SRM)方式进行检测,离子极性监测为负离子,用于定量分析的离子分别为黄豆苷元m／z 252．9,木犀草素m／z 284．8。结果:血浆中的杂质不干扰黄豆苷元和木犀草素的测定,线性范围为0．1004～80．32μg·L~(-1)(r=0．994 0),血浆中黄豆苷元的绝对回收率大于80%,浓度为0．4016,4．016和40．16μg·L~(-1)的QC样品的批内和批间精密度RSD均小于10%。结论:该方法简便准确、灵敏度高,可以用于黄豆苷元的人体药动学研究和生物等效性评价。     

LC—MS—MS法测定人体血浆中左炔诺孕酮浓度的方法学研究

目的建立人体血浆中左炔诺孕酮浓度测定的LC-MS-MS法。方法血浆中目标成分采用乙酸乙酯萃取。色谱柱为BDSHypersil C18柱（3μm，2．1mm×50mm），以水（含0．5‰甲酸）-乙腈-甲醇（18：32：50）为流动相，流速为0．20mL·min^-1，采用ESI^＋MRM方式进行离子监测。质谱检测条件：离子源电压5．0kV，加热毛细管温度：300℃，鞘气（N2）流速：20L·Min^-1，辅助气流速：2L·min^-1。结果血浆中左炔诺孕酮在0．313～40．0ng·mL^-1。线性关系良好（r=0．9993），最低定量限为0．313ng·mL^-1，方法回收率为91．0％～105．7％，萃取回收率为77．2％～80．8％，日内及日间RSD均〈15％。结论本方法灵敏、准确，适用于临床试验中生物样品定量分析。     

Simultaneous determination of albendazole metabolites, praziquantel and its metabolite in plasma by high-performance liquid chromatography-electrospray mass spectrometry

The analysis of albendazole sulfoxide, albendazole sulfone, praziquantel and trans-4-hydroxypraziquantel in plasma was carried out by high-performance liquid chromatography-mass spectrometry ((LC-MS-MS). The plasma samples were prepared by liquid-liquid extraction using dichloromethane as extracting solvent. The partial HPLC resolution of drug and metabolites was obtained using a cyanopropyl column and a mobile phase consisting of methanol:water (3:7, v/v) plus 0.5% of acetic acid, at a flow rate of 1.0 mL/min. Multi reaction monitoring detection was performed by electrospray ionization in the positive ion mode, conferring additional selectivity to the method. Method validation showed relative standard deviation (precision) and relative errors (accuracy) lower than 15% for all analytes evaluated. The quantification limit was 5 ng/mL and the linear range was 5-2500 ng/mL for all analytes. The method was used for the determination of drug and metabolites in swine plasma samples and proved to be suitable for pharmacokinetic studies.     

Rapid quantification of buprenorphine-glucuronide and norbuprenorphine-glucuronide in human urine by LC-MS-MS

A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed and validated for the determination of buprenorphine-glucuronide (BUP-G) and norbuprenorphine-glucuronide (NBUP-G) in human urine. The method included a dilution step followed by filtration through a Mini-Uniprep Filter and direct injection onto the LC column. The analytes were quantified in multiple reactions monitoring mode using one transition ion. Norbuprenorpine-d(3) (NBUP-d(3)) was used as the internal standard. The concentration ranges were 6-161 ng/mL for BUP-G and 12-295 ng/mL for NBUP-G. Recoveries determined after filtration for the analytes were 75%. The between-day precision of the method was in the range of 4.8-11%. The limits of quantification were found to be 4.6 ng/mL for BUP-G and 11.8 ng/mL for NBUP-G. Approximately 1000 samples from law enforcement, prison inmates, probation services, and hospitals were analyzed by the presented method. The ratios of drug glucuronides versus creatinine were calculated for a selection of samples (n = 151), where there was information on treatment with buprenorphine between 16 and 20 mg/day. The majority (86%) of the samples had a ratio of BUP-G/creatinine below 570 microg/g, and 76% of the samples had NBUP-G/creatinine lower than 1060 microg/g. The LC-MS-MS method proved to be robust and specific for the determination of BUP-G and NBUP-G in urine.     

Validated liquid chromatography-tandem mass spectrometric method for the quantitative determination of daidzein and its main metabolite daidzein glucuronide in rat plasma

A highly selective and sensitive liquid chromatographic-tandem mass spectrometric (LC-MS-MS) method was developed and validated to determine daidzein and its main metabolite daidzein glucuronide in rat plasma. The analytes and internal standard genistein were extracted from plasma samples by n-hexane-diethyl ether (1:4, v/v), and separated on a C18 column. The mobile phase consisted of acetonitrile-water-formic acid (80 : 20: 1, v/v/v). Detection was performed on a triple quadrupole tandem mass spectrometer by selected reaction monitoring (SRM) mode via atmospheric pressure chemical ionization (APCI) source. The method has a limit of quantification of 0.24 ng/ml. The linear calibration curves were obtained in the concentration range of 0.24-1000 ng/ml. The intra- and inter-day precisions were lower than 13.2% in terms of % RSD. The accuracy ranged from -0.5% to 2.4% in terms of % RE (relative error). This method was successfully applied to the determination of plasma concentration of daidzein and its main metabolite daidzein glucuronide in rats after an oral administration of 20 mg/kg daidzein.     

Determination and pharmacokinetic study of amlodipine in human plasma by ultra performance liquid chromatography-electrospray ionization mass spectrometry

A novel, specific and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination and pharmacokinetic study of amlodipine in human plasma. The analysis was carried out on an ACQUITY UPLC BEH C(18) column (50 mm x 2.1 mm, i.d., 1.7 microm) with gradient elution at a flow-rate of 0.35 ml/min. The mobile phase was water and acetonitrile under gradient conditions (both containing 0.3% formic acid) and nimodipine was used as the internal standard. Detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via Turbo ion spray ionization (ESI). Linear calibration curves were obtained over the concentration range 0.15-16.0 ng/ml, with a lower limit of quantification of 0.15 ng/ml. The intra- and inter-day precision (R.S.D.) values were below 15% and the accuracy (R.E.) was -2.3% to 6.9% at all three QC levels. The method was used to support clinical pharmacokinetic studies of amlodipine in healthy volunteers following oral administration.     

Simple, sensitive and rapid LC-ESI-MS method for the quantitation of lafutidine in human plasma--application to pharmacokinetic studies

A sensitive and specific liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and quantification of lafutidine in human plasma. Lafutidine and internal standard were isolated from plasma samples by liquid-liquid extraction with diethyl ether. The chromatographic separation was accomplished on a stainless-steel column (C18 Shim-pack 5 microm 150 mm x 2.0 mm i.d. Shimadzu) at a flow rate of 0.2 ml/min by a gradient elution. Detection was performed on a single quadrupole mass spectrometer by selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The method was proved to be sensitive and specific by testing six different plasma batches. Linearity was established for the range of concentrations 1.0-400.0 ng/ml with a coefficient of determination (r) of 0.9998 and good back-calculated accuracy and precision. The intra- and inter-day precision (R.S.D.%) was lower than 10% and accuracy ranged from 85 to 115%. The lower limit of quantification was identifiable and reproducible at 0.5 ng/ml with 0.2 ml plasma. The proposed method enables the unambiguous identification and quantification of lafutidine for pharmacokinetic, bioavailability or bioequivalence studies.     

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.     

Simultaneous determination of clozapine and its N-desmethyl and N-oxide metabolites in plasma by liquid chromatography/electrospray tandem mass spectrometry and its application to plasma level monitoring in schizophrenic patients

A liquid chromatography tandem mass spectrometry (LC-MS-MS) assay method for the simultaneous determination of clozapine and its N-desmethyl (norclozapine) and N-oxide metabolites in human plasma is described. The compounds were extracted from plasma by a single step liquid-liquid extraction procedure and analyzed using a high performance liquid chromatography electrospray tandem mass spectrometer system. The compounds were eluted isocratically on a C-18 column, ionized using positive ion atmospheric pressure electrospray ionization method by a TurboIonspray source and analyzed using multiple reaction monitoring mode. The ion transitions monitored were m/z 327 --> m/z 270 for clozapine, m/z 313 --> m/z 192 for norclozapine, m/z 343 --> m/z 256 for clozapine-N-oxide and m/z 421--> m/z 201 for internal standard. The standard curves of clozapine, norclozapine and clozapine-N-oxide were linear over the range of 1 ng/ml to 1000 ng/ml when 0.5 ml of plasma was used for the analysis (r(2) >0.998). Three pooled plasma samples collected from patients who were treated with clozapine were used as long-term quality control samples to check the validity of spiked standard curve samples made at various times. The intra- and inter-assay variations for the spiked standard curve and quality control samples were less than 14%. These variations for the long-term patient quality control samples were less than 11%. The LC-MS-MS assay for simultaneous determination of clozapine, norclozapine and clozapine-N-oxide reported here is highly specific, sensitive, accurate and rapid. This method is currently being used for the plasma level monitoring of clozapine and its N-desmethyl and N-oxide metabolites in patients treated with clozapine. The plasma levels of clozapine, norclozapine and clozapine-N-oxide varied widely within and among patients. The data revealed that the norclozapine and clozapine N-oxide metabolites were present at about 58%+/-14% and 17%+/-6% of clozapine concentrations in plasma, respectively.     

Determination of the oral platelet aggregation inhibitor Sibrafiban in rat, dog, and human plasma utilising HPLC-column switching combined with turbo ion spray single quadrupole mass spectrometry

A sensitive and selective HPLC-column switching method with single quadrupole mass spectrometric detection was developed for the simultaneous determination of the oral platelet aggregation inhibitor Sibrafiban (double protected prodrug), its prodrug and the active metabolite in rat, dog, and human plasma. The three analytes together with their tri-deuterated internal standards were isolated from plasma by protein precipitation (0.5 M perchloric acid). The de-proteinated samples were injected onto a standard-bore trapping column (4.0 mm i.d., LC-ABZ) of an HPLC-column switching system. Polar plasma components were removed by flushing the trapping column with ammonium formate (pH 3.6; 5 mM). Enriched compounds (including the analytes of interest) were backflushed onto a narrow-bore analytical column (2.1 mm i.d., Inertsil ODS-2) and separated by gradient elution (formic acid/ methanol). The whole effluent (200 microl/min) from the analytical column was passed to the turbo ion spray interface without splitting. Selected ion monitoring (SIM) was used for mass spectrometric detection. The limit of quantification for all three analytes was 1 ng/ml, using a 250-microl specimen of plasma. The mean precision and inaccuracy for the three analytes in all species were < 6 and < 5%, respectively. The practicability of the new analytical method was demonstrated by the analysis of about 500 rat and dog plasma and about 14,000 human plasma samples. The new method represents a successful example for the application of LC single MS with ionspray ionisation to the analysis of small molecule drugs in biological matrices from toxicokinetic studies and large clinical trials.     

Highly sensitive liquid chromatography-tandem mass spectrometry method for quantification of a new bone anabolic agent,TAK-778, in human serum

A liquid chromatography-tandem mass spectrometric (LC-MS-MS) method for the highly sensitive determination of a new bone-anabolic agent, TAK-778 in human serum was developed. The internal standard (I.S.) used was deuterated TAK-778. TAK-778 and I.S. were extracted from serum samples with diethyl ether at neutral pH. A turbo ion spray interface was used as the ion source of LC-MS-MS, and the analysis was performed in the selected reaction monitoring mode. The lower limit of quantification was 0.02 ng/ml when 0.4 ml of serum was used, and the standard curve was linear in the range of 0.02-10 ng/ml. The method was precise; the intra- and inter-day precision of the method was not more than 17.9%. The accuracy of the method was good with the deviations between added and calculated concentration of TAK-778 being typically within 9.0%.     

Stability of sufentanil in human plasma samples

The stability of sufentanil in human plasma kept under various storage conditions was investigated. Extraction was performed using solid phase extraction with new mixed-mode cation exchange Oasis MCX columns; quantification was carried out using gas chromatography equipped with a mass spectrometry detector. When plasma was left at 4 degrees C in nonsilanized tubes, concentrations of sufentanil decreased significantly during the first hour. In plasma samples kept at -25 degrees C for 8 hours in nonsilanized glass tubes, a significant decrease of sufentanil concentrations was found, with an average loss of 10.1% of the initial concentration. A significant decrease occurred when plasma was kept in silanized glass tubes for 12 hours at -25 degrees C. The current study emphasizes the importance of sampling and storage conditions for an accurate determination of sufentanil concentration in plasma.     

LC-MS／MS法测定人血浆中舒芬太尼的血药浓度

目的建立液质联用（LC—MS／MS）法测定血浆中舒芬太尼血药浓度。方法以芬太尼为内标,血浆样品经乙腈沉淀蛋白后,以Ultimate XB C18（100mm×2．1mm,3．0μm）柱为色谱柱,流动相为水-甲醇（15：85,V／V）,各含10mmol·L^-1乙酸铵,流速为0．2mL·min^-1,柱温加℃;质谱条件为电喷雾电离源（ESI）,检测方式为正离子电离、多离子反应监测（MIIM）,用于定量分析的离子为舒芬太尼m／z387．2→238．1,芬太尼m／z337．2→188．2。结果舒芬太尼线性范围为0．05～2μg·L^-1（r=0．9964）,线性关系良好。舒芬太尼的提取回收率为83．68％。88．06％。批内和批间精密度RSD均〈10％。结论本研究建立的测定舒芬太尼血药浓度的方法简单、快速、准确、灵敏,可用于临床上血药浓度监测和药动学研究。     

Development of HPLC method for the determination of levosulpiride in human plasma

A rapid and simple high performance liquid chromatography (HPLC) method was developed and validated for determination of levosulpiride in human plasma. After extraction with ethylacetate/methylene chloride (5:1, v/v), analysis of levosulpiride in plasma samples was carried out using a reverse phase C18 column with fluorescence detector (maximum excitation at 300 nm and maximum emission at 365 nm) for separation and quantification. A mixture of methanol-20 mM phosphate buffer (pH 3.5, 16:84, v/v) was used as a mobile phase. The method was specific and sensitive with a limit of quantification of 5 ng/ml. This HPLC method was validated by examining the precision and accuracy for inter- and intra-day analysis in the concentration range of 5-150 ng/ml. The relative standard deviation (R.S.D.) in inter- and intra-day validation were 8.16-19.75 and 3.90-11.69%, respectively. In stability tests, levosulpiride in human plasma was stable during the storage and assay procedure. The method was applied to the bioequivalence study of two levosulpiride tablet formulations (25 mg) after a single oral administration.     

Determination of arbidol in human plasma by LC-ESI-MS

A sensitive, specific and accurate method for determination of arbidol in human plasma was developed. Arbidol and internal standard were extracted from plasma samples by liquid-liquid extraction with diethyl ether. The chromatographic separation was accomplished on a Shiseido C18 3 microm analytical column (100 mm x 2.0 mm i.d.) at a flow rate of 0.3 mL/min isocratically. Detection was performed on a single quadrupole mass spectrometer by selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The method had a chromatographic run time of 6 min and a good linear relationship over the range 1-1000 ng/mL. The limit of quantitation for arbidol in plasma was 1 ng/mL. The intra-day and inter-day precision (R.S.D.%) was lower than 7% and accuracy ranged from 95 to 105%. The proposed method enables unambiguous identification and quantification of arbidol in vivo and has been successfully applied to study the pharmacokinetics of arbidol in healthy male Chinese volunteers.     

Solid-phase microextraction of human plasma samples for determination of sufentanil by gas chromatography-mass spectrometry

A solid-phase microextraction (SPME) method has been developed for the quantitative analysis of sufentanil from human plasma by gas chromatography-mass spectrometry (GC-MS). The immersion SPME sampling technique was optimized for the extraction of sufentanil from plasma. The influence of the pH and the ionic strength of the sample on the extraction of the analytes by the SPME fiber were investigated. Sufentanil and fentanyl (internal standard) were extracted from plasma with a 65-microm polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber for 30 minutes using salting out agents in basic conditions. The calibration curve was linear over a concentration range of 6-50 ng/mL. Intraday and interday relative standard deviations were 3.6% and 10.6%, respectively. The limit of quantification was 6 ng/mL for a plasma volume of 1 mL. With regard to selectivity, simplicity, and low cost, the SPME method described should be useful for a rapid extraction of sufentanil from human plasma.     

Simultaneous analysis of frequently used licit and illicit psychoactive drugs in breast milk by liquid chromatography tandem mass spectrometry

A liquid chromatography tandem mass spectrometry (LC-MS-MS) method for the quantification of frequently used licit (caffeine, nicotine and cotinine) and illicit drugs (opiates, cocaine, cannabinoids and amphetamines) in breast milk was developed and fully validated. Chromatography was performed on a reverse-phase column using a gradient of 2mM ammonium acetate, pH 6.6, and methyl alcohol as mobile phase at a flow rate of 0.35 mL/min. Separated analytes were quantified by electrospray ionization tandem mass spectrometry in positive ion mode using multiple reaction monitoring. Milk samples were kept at -20 °C until analysis and the compounds under investigation were extracted from the matrix by Bond Elut Certify cartridges. The concentration range covered was LOQ to 1000 ng/mL for all the investigated drugs. Intra- and inter-assay imprecision was less than 20%, analytical recovery ranged between 51.6% and 86.5%, matrix effect between 71.1% and 116.6% and process efficiency between 46.8% and 84.0%. Analytes were stable after three freeze-thaw cycles, after 6 months at -20 °C and after the pasteurization process (differences to the initial concentration always lower than 10%). matrix effect ranged from 77.6% to 116.6%, recovery from 51.6% to 86.5%, and process efficiency from 46.8% to 79.0%. This LC-MS-MS assay was applied to screen samples from the largest Spanish milk bank and samples coming from drug addicted mothers. The developed method provided adequate sensitivity and performance characteristics to prove the presence of only caffeine in a small percentage of samples from milk donating nursing mothers and the presence or absence of most commonly used illicit drugs in breast milk from addicted lactating mothers.     

Quantification of the N-desmethyl metabolite of rosuvastatin in human plasma by automated SPE followed by HPLC with tandem MS detection

A selective, accurate and precise assay was developed for the quantification in human plasma of the N-desmethyl metabolite of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor rosuvastatin. The assay-employing automated SPE followed by HPLC with positive ion electrospray tandem MS (HPLC-MS/MS)-was validated. The standard curve range for N-desmethyl rosuvastatin in human plasma was 0.5-30 ng/ml with 0.5 ng/ml being the limit of quantification. Plasma samples were mixed 1:1 with sodium acetate buffer (pH 4.0; 0.1M) soon after separation from red blood cells. N-Desmethyl rosuvastatin was stable in plasma:buffer at room temperature for 24h and at -70 degrees C for 12 months. The assay was applied successfully to the quantification of N-desmethyl rosuvastatin in human plasma following administration of rosuvastatin.     

Determination of myrtucommulone from Myrtus communis in human and rat plasma by liquid chromatography/tandem mass spectrometry

Recent studies revealed that the non-prenylated acylphloroglucinol myrtucommulone (MC) from myrtle ( MYRTUS COMMUNIS) potently suppresses the biosynthesis of eicosanoids by direct inhibition of cyclooxygenase-1, microsomal prostaglandin E2 synthase (mPGES)-1, and 5-lipoxygenase at IC?? values in the range of 1 to 29 μM. Moreover, MC showed potent efficacy in animal models of inflammation after intraperitoneal administration. Since the main prerequisite for therapeutic efficacy is sufficient bioavailability, it is important to evaluate whether the concentrations of MC achieved in plasma coincide with the pharmacological active concentrations determined in vitro. For that reason, a sensitive LC/MS/MS method has been developed and validated for the determination of MC in human plasma. This method is based on liquid-liquid extraction of plasma samples with 20 % ethyl acetate in tert-butyl methyl ether using the structurally related acylphloroglucinol hyperforin as the internal standard. Chromatographic separation was achieved on a Gemini C6 Phenyl column using a mixture of acetonitrile/water (85 : 15 v/v) containing 6 mM ammonium formate in a run time of 15 min at a flow rate of 1 mL/min, a column temperature of 40 °C, and an autosampler temperature of 5 °C. Mass spectrometric quantification was carried out in the negative ion mode using electrospray ionization (ESI) and multiple-reaction monitoring (MRM). The most intense [M-H]? MRM transition at m/z 667.4 → m/z 194.9 was used for quantification of MC and the transition at m/z 535.4 to m/z 383.2 was used to monitor hyperforin. The method was linear in the range of 1-100 ng/mL with r > 0.998, an intra- and inter-day RSD of 1.1-8.4 and 7.1-11.8 %, respectively, and a maximum R. E. of 13.8 % at the lowest concentration level. Moreover, cross validation revealed the suitability of the developed LC/MS method for application in rat studies.     

Simple method for determination of triazolam in human plasma by high-performance liquid chromatography/tandem mass spectrometry

Triazolam was analyzed from human plasma samples by high-performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) with an MSpak GF polymer column (50 mm x 4.6 mm i.d., particle size 6 microm), which enabled direct injection of crude biological samples. Separation of triazolam, and lorazepam as the internal standard (IS) was carried out using 10mM ammonium acetate (pH 3.56)-0.1% formic acid and an acetonitrile gradient elution. Both compounds formed base peaks due to [M + H]+ ions by HPLC/ESI-MS, and product ions were produced from each [M + H]+ ion as seen by HPLC-MS/MS. Quantification of triazolam and the IS in plasma samples was made by selective reaction monitoring using each base peak of product ions of HPLC-MS/MS. The recovery range of triazolam spiked into plasma was 86.4-92.7%. The regression equation for triazolam showed excellent linearity in the range of 0.25-20 ng/mL, and the detection limit was 0.1 ng/mL. Intra- and inter-day precisions for triazolam in plasma samples were not greater than 12.4%. Accuracy for the drug was in the range of 88.0-101.4%. Data obtained after oral administration of triazolam in male and female subjects are also presented.