高效液相色谱串联质谱法测定人血浆中吲达帕胺浓度及生物等效性研究

目的:建立一种简单、有效且灵敏的液质联用法(LC-MS/MS)检测人血浆中吲达帕胺浓度。方法:血浆样品经叔丁基甲基醚(tert-ButylMethyl Ether,MTBE)萃取后,选安定作内标。色谱柱为Luna C18柱(150mm×2.0mm,5μm);流动相为10mmol/L甲酸铵(含0.1%甲酸):甲醇=(20∶80,V/V);流速为0.30mL/min;采用ESI+MRM方式监测;源电压:3.5kV;源温度:100℃;吲达帕胺和安定的离子选择通道分别为:m/z 366.2→132.1,285.2→154.1。结果:吲达帕胺线性范围为0.536～45.733ng/mL,最低检测浓度为0.536ng/mL,提取回收率在69%～81%,日内、日间RSD均<15%。由湖南协力药业有限公司生产生产的吲达帕胺缓释片(1.5mg/片)与施维雅(天津)制药有限公司生产的吲达帕胺缓释片(商品名:纳催离,1.5mg/片)经单次及多次给药试验研究,具有生物等效性。结论:本方法简单、灵敏,可准确检测人体血浆中吲达帕胺的浓度。     

Determination of mianserin in human plasma by high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI/MS): application to a bioequivalence study in Chinese volunteers

This study aims to develop a standard protocol for the bioequivalence study of mianserin hydrochloride tablets--a tetracyclic antidepressant drug. For this purpose, a rapid, convenient and selective method using high performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI/MS) has been developed and validated to determine mianserin in human plasma. Mianserin and the internal standard (I.S.), cinnarizine were extracted from plasma by N-hexane:dimethylcarbinol (98:2, v/v) after alkalinized with sodium hydroxide. LC separation was performed on a Thermo Hypersil-Hypurity C18 (5 microm, 150 mm x 2.1 mm) with the mobile phase consisting of 10mM ammonium acetate (pH 3.4)-methanol-acetonitrile (35:50:15, v/v/v) at 0.22 ml/min. The retention time of mianserin and cinnarizine was 3.4 and 2.1 min, respectively. Quadrupole MS detection and quantitation was done by monitoring at m/z 265 [M+H]+ for mianserin and m/z 369 [M+H]+ for cinnarizine. The method was validated over the concentration ranges of 1.0-200.0 ng/ml for mianserin. The recovery was 81.3-84.1%, intra- and inter-day precision of the assay at three concentrations were 9.6-11.4% with accuracy of 97.5-101.2% and the lower limit of quantitation (LLOQ) detection was 1.0 ng/ml for mianserin. The stability of compounds was established in a battery of stability studies, i.e., short-term and long-term storage stability as well as freeze-thaw cycles. This method proved to be suitable for the bioequivalence study of mianserin hydrochloride tablets in healthy human male volunteers.     

Simultaneous determination of irbesartan and hydrochlorothiazide in human plasma using HPLC coupled with tandem mass spectrometry: Application to bioequivalence studies

A sensitive, specific and selective liquid chromatography/tandem mass spectrometric method has been developed and validated for the simultaneous determination of irbesartan and hydrochlorothiazide in human plasma. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard losartan were separated on a reverse phase C₁₈ column (50 mm × 4 mm, 3 μm) using water with 2.5% formic acid, methanol and acetonitrile (40:45:15, v/v/v (%)) as a mobile phase (flow rate of 0.70 mL/min). Irbesartan and hydrochlorothiazide were ionized using ESI source in negative ion mode, prior to detection by multiple reaction monitoring (MRM) mode while monitoring at the following transitions: m/z 296 → 269 and m/z 296 → 205 for hydrochlorothiazide, 427 → 175 for irbesartan. Linearity was demonstrated over the concentration range 0.06–6.00 μg/mL for irbesartan and 1.00–112.00 ng/mL for hydrochlorothiazide. The developed and validated method was successfully applied to a bioequivalence study of irbesartan (300 mg) with hydrochlorothiazide (12.5 mg) tablet in healthy volunteers (N = 36).     

Simultaneous determination of lansoprazole and its metabolites 5'-hydroxy lansoprazole and lansoprazole sulphone in human plasma by LC-MS/MS: application to a pharmacokinetic study in healthy volunteers

A highly sensitive and specific liquid chromatography coupled with tandem mass spectrometric (LC-MS/MS) method has been developed and validated for the simultaneous determination of lansoprazole and its metabolites 5'-hydroxy lansoprazole and lansoprazole sulphone. The detection was operated with multiple reaction-monitoring (MRM) using the electrospray ionization technique. The assay procedure involved precipitation of plasma samples with acetonitrile after indapamide was added as internal standard (IS). The chromatographic separation was achieved with a mixture of methanol-0.2% ammonium acetate and 0.1% methanoic acid in water (75:25, v/v) as mobile phase on an Inertsil ODS-3 column. The method was proved to be accurate and precise with linearity ranges of 10-4,000 ng/ml, 5.0-400 ng/ml, and 1.0-400 ng/ml for lansoprazole, 5'-hydroxy lansoprazole and lansoprazole sulphone, respectively, with the correlation coefficients (r) better than 0.999. The lower limits of quantification (LLOQ) were 2.0 ng/ml, 2.0 ng/ml, and 0.5 ng/ml for lansoprazole, 5'-hydroxy lansoprazole and lansoprazole sulphone, respectively. The intra- and inter-day precision and accuracy values were found to be within the assay variability limits (R.S.D.% within +/-15) in accordance with FDA guidelines. The validated LC-MS/MS method has been successfully applied for the determination of lansoprazole and its metabolites in human plasma.     

Determination of clarithromycin in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry

A rapid and sensitive method has been developed for the determination of clarithromycin in human plasma with liquid chromatography-tandem mass spectrometry. Clarithromycin and the internal standard, telmisartan were precipitated from the matrix (50 microl) with 200 microl acetonitrile and separated by HPLC using formic acid:10 mM ammonium acetate:methanol (1:99:400, v/v/v) as the mobile phase. The assay based on detection by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring mode was finished within 2.4 min. Linearity was over the concentration range 10-5000 ng/ml with a limit of detection of 0.50 ng/ml. Intra- and inter-day precision measured as relative standard deviation were <3.73% and <9.93%, respectively. The method was applied in a bioequivalence study of two tablet formulations of clarithromycin.     

HPLC-MS-MS法测定人血浆中芬太尼浓度及其生物等效性研究

目的:建立液相色谱-串联质谱法(HPLC-MS-MS)测定人血浆中芬太尼的浓度。方法:以D5-芬太尼为内标,采用正己烷处理血浆样品。色谱柱为Thermo Hypurity C18(150mm×2.1mm,5μm),流动相为甲醇∶水(含0.1%甲酸)=(85∶15,V/V),流速为0.3mL/min,柱温40℃;质谱条件为电喷雾电离源(ESI),检测方式为正离子方式、多离子反应监测(MRM),用于定量分析的离子为芬太尼m/z 337.1→188.1,D5-芬太尼m/z 341.9→187.9。结果:芬太尼血药浓度在19.53～5000pg/mL范围内线性关系良好,定量下限为19.53pg/mL,日内和日间变异均小于5.16%,提取回收率均在90%以上;应用此方法研究了24名健康男性受试者使用两种芬太尼透皮贴剂的药代动力学特点,受试制剂对参比制剂的相对生物利用度为(94.0±19.5)%。结论:本法具有快速、简便、灵敏、准确等特点,适合人血浆中芬太尼浓度测定。两种制剂生物等效。     

Investigation of plasma concentrations of paracetamol,metacetamol, and orthocetamol in Japanese racehorses using liquid chromatography–electrospray ionisation–tandem mass spectrometry

Paracetamol is used widely as an over‐the‐counter analgesic and antipyretic medication for humans, but not for Japanese racehorses. Paracetamol can be an environmental substance, and is found together with its two isomers, metacetamol and orthocetamol, in equine urine. However, the sources and routes of paracetamol exposure remain unclear. To control the misuse of paracetamol, it is appropriate to establish residue limits for paracetamol to differentiate the administration of paracetamol from its environmental levels. In this study, we developed and validated a quantitative method for paracetamol, metacetamol, and orthocetamol in equine plasma using liquid chromatography–electrospray ionization–tandem mass spectrometry and applied it to postrace samples from 320 Japanese racehorses for approximately 1 year. In addition, we conducted feed analysis and related pharmacokinetics simulations to evaluate the contributions from exposure via feed. The hydrolyzed plasma concentrations of paracetamol, metacetamol, and orthocetamol ranged from 0.787 to 39.8 ng/mL (median 5.87 ng/mL), 0 to 2.13 ng/mL (0.347 ng/mL), and 1.98 to 82.8 ng/mL (16.6 ng/mL), respectively. Such low concentrations of paracetamol were deemed irrelevant to therapeutic effect. Based on statistical analysis, the preliminary Japanese residue limits of unhydrolyzed and hydrolyzed paracetamol were determined to be 70.5 ng/mL and 112 ng/mL, respectively, in plasma, at a risk factor of 1 in 10,000. Furthermore, we detected paracetamol and orthocetamol in feed samples. A pharmacokinetics simulation showed that the presence of orthocetamol is most probably related to daily feed rations. As for paracetamol, feed can be one of the sources and other possible sources require further investigation.     

Amlodipine bioequivalence study: quantification by liquid chromatography coupled to tandem mass spectrometry

OBJECTIVE: To assess the bioequivalence of two amlodipine tablet formulations (Amlodipine 5 mg tablet from Merck S.A. Indústrias Químicas, Brazil as test formulation and Norvasc 5 mg tablet from Laboratórios Pfizer Ltd., Brazil as reference formulation) in 24 healthy volunteers of both sexes. METHODS: The study was conducted using an open, randomized two-period crossover design with a 4-week washout interval. Plasma samples were obtained over a 144 h period. Plasma amlodipine concentrations were analyzed by combined liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reaction monitoring (MRM). From the amlodipine plasma concentration vs time curves, the following pharmacokinetic parameters were obtained: AUC(last), AUC(0-inf) and C(max). The statistical interval proposed was 80-125% according to the US Food and Drug Administration Agency. RESULTS: The limit of quantification was 0.1 ng/ml for plasma amlodipine analysis. The geometric mean and the 90% confidence interval (CI) test/reference ratios were 101.2 (92.9-110.2%) for AUC(last), 99.6 (91.5-108.4%) for AUC(0-inf) and 98.5 (89.0-109.1%) for C(max). CONCLUSION: Since the 90% CI for AUC(last), AUC(0-inf) and C(max) ratios were within in the 80-125% interval proposed by the US FDA, it was concluded that Amlodipine 5 mg tablet (test formulation) was bioequivalent to Norvasc 5 mg tablet, in terms of both rate and extent of absorption.     

Determination of loratadine and its active metabolite in human plasma by high-performance liquid chromatography with mass spectrometry detection

A new sensitive and selective liquid chromatography coupled with mass spectrometry (LC/MS/MS) method for quantification of loratadine (LOR) and its active metabolite descarboethoxyloratadine (DSL) in human plasma was validated. After addition of the internal standard, metoclopramide, the human plasma samples (0.3 ml) were precipitated using acetonitrile (0.75 ml) and the centrifuged supernatants were partially evaporated under nitrogen at 37 degrees C at approximately 0.3 ml volume. The LOR, DSL and internal standard were separated on a reversed phase column (Zorbax SB-C18, 100 mmx3.0 mm i.d., 3.5 microm) under isocratic conditions using a mobile phase of an 8:92(v/v) mixture of acetonitrile and 0.4% (v/v) formic acid in water. The flow rate was 1 ml/min and the column temperature 45 degrees C. The detection of LOR, DSL and internal standard was in MRM mode using an ion trap mass spectrometer with electrospray positive ionisation. The ion transitions were monitored as follows: 383-->337 for LOR, 311-->(259+294+282) for DSL and 300-->226.8 for internal standard. Calibration curves were generated over the range of 0.52-52.3 ng/ml for both LOR and DSL with values for coefficient of determination greater than 0.994 by using a weighted (1/y) quadratic regression. The lower limits of quantification were established at 0.52 ng/ml LOR and DSL, respectively, with an accuracy and precision less than 20%. Both analytes demonstrated good short-term, long-term, post-preparative and freeze-thaw stability. Besides its simplicity, the sample treatment allows obtaining a very good recovery of both analytes, around 100%. The validated LC/MS/MS method has been applied to a pharmacokinetic study of loratadine tablets on healthy volunteers.     

高效液相色谱-质谱/质谱联用法测定人血浆中莫沙必利

建立测定人血浆中莫沙必利的高效液相色谱-质谱/质谱联用法。取血浆样品经液-液萃取后，以乙腈为有机相，0.3%甲酸水溶液为水相，采用梯度洗脱的方式，用C₁₈柱分离，通过电喷雾离子化，以多反应监测(MRM)方式进行正离子检测。莫沙必利线性范围为0.17~68.00 ng·mL^-1，定量下限为0.17 ng·mL^-1，每个样品测试时间仅2.8 min，日内、日间精密度(RSD)均小于13%，准确度(RE)在±6.3%范围内。应用此法研究了20名志愿者单剂量口服枸橼酸莫沙必利片后的药代动力学特点。该方法、灵敏、准确、快速，适用于莫沙必利的药代动力学及生物等效性研究。     

PMEA-Na在beagle犬血浆中的液相色谱/质谱/质谱联用法测定及其药代动力学

目的建立LC/MS/MS法测定犬血浆中PMEA-Na浓度,进行其药代动力学研究.方法血浆样品经甲醇沉淀蛋白后,采用多反应监测法测定其血药浓度.色谱柱为Xterra MS柱,流动相为甲醇水甲酸(25750.5),流速为 0.25 ml·min-1.Beagle犬分3个剂量组经静脉给药,给药剂量分别为 1.0、3.0 和 6.0 mg·kg-1.药代动力学参数通过DAS软件计算获得.结果PMEA-Na线性范围0.02～20 mg·L-1 (r=0.999);最低检测浓度为 20 μg·L-1,方法回收率为 97.1%～107.3%,日内日间变异分别小于 6.5%、10.8%.beagle 犬在 1.0, 3.0 与 6.0 mg·kg-1剂量下单次iv PMEA-Na后,测得其AUC分别为 2.3±0.5, 8.2±1.3 and 18.5±1.3 mg·L-1·h; t1/2 为 3.9±1.8, 8.4±1.5 and 8.9±0.6 h; CL为 0.44±0.09, 0.35±0.05 and 0.31±0.03 ml·h-1·kg-1.结论本方法专属性强,准确性好,可用于PMEA-Na血药浓度测定和药代动力学研究.     

Determination of olprinone in human plasma utilizing liquid chromatography tandem mass spectrometry

A sensitive and rapid method was developed for quantification of olprinone in human plasma utilizing liquid chromatography tandem mass spectrometry (LC–MS/MS). An aliquot of 1 mL plasma sample was extracted with ethyl acetate–dichloromethane. Separation of olprinone and the milrinone (internal standard, IS) from the interferences was achieved on a C₁₈ column followed by MS/MS detection. The analytes were monitored in the positive ionization mode. Multiple reaction monitoring using the transition of m/z 251 → m/z 155 and m/z 212 → m/z 140 was performed to quantify olprinone and IS, respectively. The method had a total chromatographic run time of 3 min and linear calibration curves over the concentration range of 0.5–60 ng/mL. The lower limit of quantification (LLOQ) was 0.5 ng/mL. The intra- and inter-day precisions were less than 16.3% for low QC level, and 7.1% for other QC levels, respectively. The intra- and inter-day relative errors were ranged between −12.2% and 3.7% for three QC concentration levels. The validated method was successfully applied to the quantification of olprinone concentration in human plasma after intravenous (i.v.) administration of olprinone at a constant rate of infusion of 2 μg/(kg min) for 5 min in order to evaluate the pharmacokinetics.     

Terbinafine quantification in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry: application to a bioequivalence study.

A method based on liquid chromatography with positive ion electrospray ionization and tandem mass spectrometry is described for the determination of terbinafine in human plasma using naftifine as internal standard. The method has a chromatographic run time of 5 minutes and was linear in the range 1.0 to 2000 ng/mL. The limit of quantification was 1.0 ng/mL; the intraday precision was 3.6%, 3.8%, 3.5%, and 4.1%; and the intraday accuracy was -2.7%, 7.7%, 4.8%, and -2.7% for 5.0, 80.0, 250.0, and 1500.0 ng/mL, respectively. The interday precision was 4.9%, 1.7%, 2.4%, and 4.6% and the interday accuracy was 0.3%, 5.8%, 6.5%, and -1.4% for the same concentrations. This method was used in a bioequivalence study of two tablet formulations of terbinafine. Twenty-four healthy volunteers (both sexes) received a single oral dose of terbinafine (250 mg) in an open, randomized, two-period crossover study. The 90% CI of geometric mean ratios between Terbinafina (Medley S/A Indústria Farmacêutica, Campinas, Brazil) and Lamisil (Novartis Biociências S/A, S?o Paulo, Brazil) were 90.5% to 110.0% for C max, 92.2% to 108.1% for AUC last, and 91.3% to 107.5% for AUC 0-inf. Because the 90% CI for the above-mentioned parameters were included in the 80% to 125% interval proposed by the US FDA, the two formulations were considered bioequivalent in terms of rate and extent of absorption.     

Rapid determination of nine barbiturates in human whole blood by liquid chromatography‐tandem mass spectrometry

A rapid, simple and sensitive liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method was developed for the qualitative and quantitative analysis of nine barbiturates (barbital, phenobarbital, pentobarbital, amobarbital, secobarbital, thiopental, butalbital, butabarbital, and hexobarbital) in human whole blood. Barbiturates were extracted from 100 μL of human whole blood samples using a simple liquid‐liquid extraction (LLE) procedure, and detected by LC‐MS/MS. An UPLC C18 (2.1 mm × 100 mm, 1.7 µm) column was used at 40 °C for the separation and acetonitrile/water system was used as the mobile phase with gradient elution. This method showed excellent accuracy (86–111%) and precision (relative standard deviation <15%). The limits of detection (LODs) were 0.2 ng/mL for barbital and secobarbital and 0.5 ng/mL for the other barbiturates. The linearity ranged from 2 ng/mL to 2000 ng/mL, with r² > 0.99 over the range. This method achieved the separation and detection of pentobarbital and amobarbital at the same time in a convenient way. Moreover, it was both simple and sensitive for the determination of nine most commonly used barbiturate drugs, which was meaningful in the field of clinical and forensic toxicology. Copyright © 2016 John Wiley & Sons, Ltd.     

Analysis of 30 synthetic cannabinoids in oral fluid using liquid chromatography‐electrospray ionization tandem mass spectrometry

In recent years, the analysis of synthetic cannabinoids in human specimens has gained enormous importance in the broad field of drug testing. Nevertheless, the considerable structural diversity among synthetic cannabinoids already identified in ‘herbal mixtures’ hampers the development of comprehensive analytical methods. As the identification of the main metabolites of newly appearing substances is very laborious and time‐consuming, the detection of the parent compounds in blood samples is the current approach of choice for drug abstinence testing. Whenever blood sampling is not possible however, the need for alternative matrices arises. In this article, we present a fully validated liquid chromatography‐electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS) method for the analysis of 30 synthetic cannabinoids in oral fluid samples collected with the Dräger DCD 5000 collection device. The method proved to be suitable for the quantification of 28 substances. The limits of detection were in the range from 0.015 to 0.9 ng/ml, while the lower limits of quantification ranged from 0.15 to 3.0 ng/ml. The method was successfully applied to 264 authentic samples during routine analysis. A total of 31 samples (12%) was tested positive for at least one of the following synthetic cannabinoids: AM‐694, AM‐2201, JWH‐018, JWH‐019, JWH‐081, JWH‐122, JWH‐203, JWH‐210, JWH‐250, JWH‐307, MAM‐2201, and RCS‐4. Given that stabilization of the collection pads after sampling is warranted, the collection device provides satisfactory sensitivity. Hence, whenever blood sampling is not possible, the Dräger DCD 5000 collection device offers a good tool for the analysis of synthetic cannabinoids in oral fluid in the broad field of drug testing. Copyright © 2012 John Wiley & Sons, Ltd.     

Determination of febuxostat in human plasma using ultra‐performance liquid chromatography tandem mass spectrometry

A rapid and sensitive liquid chromatography‐tandem mass spectrometry method has been developed and validated for the determination of febuxostat in human plasma. The liquid‐liquid extraction technique was used for the extraction of febuxostat from human plasma using trandolapril as the internal standard (IS). Chromatography was performed on a ultra‐performance liquid chromatography (UPLC) BEH C18, 50 mm X 2.1 mm, 1.7 µm particle size column, with the mobile phase consisting of 0.1% formic acid and acetonitrile (in a 25:75 ratio), followed by detection using mass spectrometry. The method involves a simple reversed isocratic chromatography condition and mass spectrometry detection, which enables detection at sub‐microgram levels. The method was validated and the lower limit of quantification for febuxostat was found to be 0.075 µg/ml. The mean recovery for febuxostat ranged from 100.9 to 106.5%. This method increased the sensitivity and selectivity; resulting in high‐throughput analysis of febuxostat using commercially available IS for pharmacokinetic, bioavailability, and bioequivalence studies, with a chromatographic run time of 1.5 min only. Copyright © 2012 John Wiley & Sons, Ltd.     

Simultaneous detection and quantitation of organic impurities in methamphetamine by ultra‐high‐performance liquid chromatography–tandem mass spectrometry,a complementary technique for methamphetamine profiling

The analysis of organic impurities plays an important role in the impurity profiling of methamphetamine, which in turn provides valuable information about methamphetamine manufacturing, in particular its synthetic route, chemicals, and precursors used. Ultra‐high‐performance liquid chromatography – tandem mass spectrometry (UHPLC – MS/MS) is ideally suited for this purpose due to its excellent sensitivity, selectivity, and wide linear range in multiple reaction monitoring (MRM) mode. In this study, a dilute‐and‐shoot UHPLC – MS/MS method was developed for the simultaneous identification and quantitation of 23 organic manufacturing impurities in illicit methamphetamine. The developed method was validated in terms of stability, limit of detection (LOD), lower limit of quantification (LLOQ), accuracy, and precision. More than 100 illicitly prepared methamphetamine samples were analyzed. Due to its ability to detect ephedrine/pseudoephedrine and its high sensitivity for critical target markers (eg, chloro‐pseudoephedrine, N‐cyclohexylamphetamine, and compounds B and P), more impurities and precursor/pre‐precursors were identified and quantified versus the current procedure by gas chromatography – mass spectrometry (GC – MS). Consequently, more samples could be classified by their synthetic routes. However, the UHPLC – MS/MS method has difficulty in detecting neutral and untargeted emerging manufacturing impurities and can therefore only serve as a complement to the current method. Despite this deficiency, the quantitative information acquired by the presented UHPLC – MS/MS methodology increased the sample discrimination power, thereby enhancing the capacity of methamphetamine profiling program (MPP) to conduct sample‐sample comparisons.     

Liquid chromatography tandem mass spectrometry assay for the simultaneous determination of venlafaxine and O-desmethylvenlafaxine in human plasma and its application to a bioequivalence study

A rapid, simple and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for simultaneous determination of venlafaxine (VEN) and its active metabolite, O-desmethylvenlafaxine (ODV) in human plasma was developed using nadolol as internal standard (IS). The analytes and IS were extracted from 200 microl aliquots of human plasma via protein precipitation using 0.43% formic acid in acetonitrile and separated on a Hypurity cyano (50 mm x 4.6 mm, 5 microm) column. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring (MRM) and positive ion mode. The precursor to product ion transitions monitored for VEN, ODV and IS were m/z 278.3-->58.1, 264.3-->58.1 and 310.4-->254.1, respectively. The total chromatographic runtime was 3 min with retention time for VEN, ODV and IS at 1.93, 1.50 and 1.29 min, respectively. The method was fully validated for its sensitivity, accuracy and precision, linearity, recovery, matrix effect, dilution integrity and stability studies. The linear dynamic range of 2.0-500 ng/ml was established for both VEN and ODV with mean correlation coefficient (r), 0.9994 and 0.9990, respectively. The intra-batch and inter-batch precision (%CV) in three validation batches across five concentration levels (LLOQ, LQC, MQC, HQC and ULOQ) was less than 12.6% for both the analytes. The accuracy determined at these levels was within -9.8 to +3.9% in terms of %bias. The method was successfully applied to a bioequivalence study of 150 mg venlafaxine extended release capsule formulation in 22 healthy Indian male subjects under fed condition.     

Simple and rapid screening procedure for 143 new psychoactive substances by liquid chromatography‐tandem mass spectrometry

In recent years, many new psychoactive substances (NPS) from several drug classes have appeared on the drug market. These substances, also known as ‘legal highs’, belong to different chemical classes. Despite the increasing number of NPS, there are few comprehensive screening methods for their detection in biological specimens. In this context, the purpose of this study was to develop a fast and simple liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) screening procedure for NPS in blood. The elaborated method allows the simultaneous screening of 143 compounds from different groups (number of compounds): cathinones (36), phenethylamines (26), tryptamines (18), piperazines (9), piperidines (2), synthetic cannabinoids (34), arylalkylamines (7), arylcyclohexylamines (3), aminoindanes (2), and other drugs (6). Blood samples (0.2 mL) were precipitated with acetonitrile (0.6 mL). The separation was achieved with gradient mobile phase of 0.1% formic acid in acetonitrile and 0.1% formic acid in water in 14 min. Detection of all compounds was based on multiple reaction monitoring (MRM) transitions. The total number of transitions monitored in dynamic mode was 432. The whole procedure was rapid and simple. The limits of detection (LODs) estimated for 104 compounds were in the range 0.01–3.09 ng/mL. The extraction recoveries determined for 32 compounds were from 1.8 to 133%. The procedure was successfully applied to the analysis of forensic blood samples in routine casework. The developed method should have wide applicability for rapid screening of new drugs of abuse in forensic or clinical samples. The procedure can be easily expanded for more substances. Copyright © 2015 John Wiley & Sons, Ltd.     

Sensitive quantification of the somatostatin analog AP102 in plasma by ultra‐high pressure liquid chromatography–tandem mass spectrometry and application to a pharmacokinetic study in rats

AP102 is a di‐iodinated octapeptide somatostatin agonist (SSA) designed to treat acromegaly and neuroendocrine tumors. A sensitive and selective method was validated for the quantification of AP102 in plasma following the European Medicines Agency (EMA) and Food and Drug Administration (FDA) guidelines. Sample preparation was performed using solid‐phase extraction microplates. Chromatographic separation was achieved on an ultra‐high pressure liquid chromatography (UHPLC) C18 column in 6.0 minutes. The compounds were quantified using multiple reaction monitoring on a tandem quadrupole mass spectrometer with ¹³C,¹⁵N‐labeled AP102 as internal standard. Calibration ranged from 50 to 10000 pg/mL. The lower limit of quantification (LLOQ) was measured at 20 pg/mL, and robust analytical performances were obtained with trueness at 99.2%–100.0%, intra‐assay imprecision at 2.5%–4.4%, and inter‐assay imprecision at 8.9%–9.7%. The accuracy profiles (total error) built on the 3 concentrations levels showed accuracy within the 70%–130% range. AP102 is remarkably stable since no proteolytic fragments were detected on plasma samples analyzed by Orbitrap‐MS. Pharmacokinetic studies were conducted in rats, after single dose (1, 3, and 10 μg/kg, sc) and continuous subcutaneous administration (osmotic minipumps for 28 days, 3.0 or 10.0 μg/kg/h). AP102 showed a rapid absorption by the subcutaneous route (T_max: 15–30 minutes) and a fast elimination (t_1/2: 33–86 minutes). The PK profile of AP102 exhibited a mean clearance of 1.67 L/h and a mean distribution volume at steady state of 7.16 L/kg, about 10‐fold higher than those observed with other SSA or non‐ and mono‐iodinated AP102. LogD_7.4 determination confirmed the lipophilic properties of AP102 that might influence its distribution in tissues.