LC-MS/MS法检测西维来司他原料药中的降解产物

目的：探讨应用液相色谱-串联质谱法（LC-MS/MS）检测西维来司他原料药中的降解产物.方法：以乙腈-水-甲酸（40：60：0.1）为流动相,待测物经Hypersil C18柱分离,电喷雾串联质谱在线检测,获得相关的色谱和质谱信息.结果：在所应用的条件下,西维来司他与其降解产物达到了很好分离,主成分和其降解产物峰的保留时间分别为18.46和3.36min,同时通过两者的质谱特征获得了降解产物的结构信息.结论：所建立的方法能快速、准确地分离鉴定西维来司他原料药中的降解产物,从而可以对其原料药进行质量控制.     

液相色谱-串联质谱法测定健康人体血浆中米格列醇浓度及其药代动力学研究

目的建立测定血浆中米格列醇片(降血糖药)的液相色谱-串联质谱法,考察米格列醇在中国健康志愿者体内的药代动力学。方法血浆样品经液-液提取后,进行色谱分离,在三重四极杆串联质谱仪上,以多反应离子监测(MRM)方式进行定量分析,用于监测的离子为m/z 208．3→m／z 146．1 (米格列醇)和m/z 268．5→m/z 250．4(内标,伏格列波糖)。结果米格列醇的最低定量浓度为5．0 μg·L-1,线性范围为5～2 000 μg·L-1,精密度与准确度符合生物样品分析要求。结论该法操作简便、快速、灵敏度高,适于临床药代动力学研究。     

LC/MS/MS法测定血浆中左羟丙哌嗪浓度及其药代动力学

目的建立测定血浆中左羟丙哌嗪的液相色谱-串联质谱法，考察左羟丙哌嗪在中国健康志愿者体内的药代动力学行为。方法血浆样品经液-液提取后，进行色谱分离，在三重四极杆串联质谱仪上，以多重反应离子监测(MRM)方式进行定量分析，用于监测的离子为m/z 237 → m/z 120（左羟丙哌嗪）和m/z 288 → m/z 58(佐米曲普坦，内标)。结果左羟丙哌嗪的最低定量浓度为0.25 μg·L^-1，线性范围为0.25-500.0 μg·L^-1，精密度与准确度符合生物样品分析要求。结论该法操作简便、快速、灵敏度高。可检测出健康志愿者po左羟丙哌嗪60 mg,其24 h后的血药浓度，适于临床药代动力学研究。     

Stability of curcumin in buffer solutions and characterization of its degradation products

The degradation kinetics of curcumin under various pH conditions and the stability of curcumin in physiological matrices were investigated. When curcumin was incubated in 0.1 M phosphate buffer and serum-free medium, pH 7.2 at 37°C, about 90% decomposed within 30 min. A series of pH conditions ranging from 3 to 10 were tested and the result showed that decomposition was pH-dependent and occurred faster at neutral-basic conditions. It is more stable in cell culture medium containing 10% fetal calf serum and in human blood; less than 20% of curcumin decomposed within 1 h, and after incubation for 8 h, about 50% of curcumin is still remained. Trans-6-(4′-hydroxy-3′-methoxyphenyl)-2,4-dioxo-5-hexenal was predicted as major degradation product and vanillin, ferulic acid, feruloyl methane were identified as minor degradation products. The amount of vanillin increased with incubation time.     

LC/MS/MS法测定血浆、羊水中曲马多及其活性代谢物氧去甲基曲马多LC/MS/MS法测定血浆、羊水中曲马多及其活性代谢物氧去甲基曲马多

目的建立液相色谱-串联质谱法(LC/MS/MS)同时测定血浆和羊水中曲马多和氧去甲基曲马多，并研究其在母体和胎儿体内分布。方法生物样本经液-液提取，通过液相色谱-串联质谱，以选择离子反应监测(SRM)方式进行检测。结果测定血浆样品曲马多和氧去甲基曲马多的线性范围为8.0~800.0 μg·L^-1；测定羊水样品曲马多和氧去甲基曲马多的线性范围为1.0~400.0 μg·L^-1。12例剖宫产产妇术前im盐酸曲马多(1.5 mg·kg^-1)后，血浆中曲马多和氧去甲基曲马多浓度较高，羊水中曲马多浓度较低，且未检测出氧去甲基曲马多。结论本方法操作简便、灵敏度高，可用于临床药代动力学研究。     

Plasma assay for the antineoplastic agent VP 16-213 (etoposide) using high-performance liquid chromatography with electrochemical detection

A sensitive high-performance liquid chromatographic (HPLC) assay of the antineoplastic agent VP 16-213 (etoposide) in plasma is described. The system discriminates between the parent compound and possible metabolites, including the aglycone and the cis isomer. After extraction with 1,2-dichloroethane the drugs are chromatographed on a reversed-phase phenyl column with amperometric detection. Quantitative response is linear up to 250 ng/ml for 1 ml human plasma and up to 40.0 mug/ml for 0.1 ml human plasma. The detection limit is ca 2 ng/ml in plasma. Preliminary pharmacokinetic results show that the sensitivity and selectivity of the assay are adequate to establish plasma concentrations over 8-12 half-lives during elimination of the drug.     

Fast chiral chromatographic method development and validation for the quantitation of eszopiclone in human plasma using LC/MS/MS

Traditional chiral chromatographic separation method development is time consuming even for an experienced chromatographer. This paper describes the application of computer software ACD Lab^® to facilitate the development of chiral separation for the quantitation of eszopiclone using LC–MS/MS technology. Assisted by ACD/Chrom Manager and LC Simulator software, the optimal chiral chromatographic development was completed within hours. The baseline chiral separation was achieved with a total cycle time of 3 min. For sample extraction method development, a Waters Oasis^® Sorbent Selection Plate containing four different sorbents was utilized. Optimal conditions were determined using a single plate under various load, wash and elution conditions. This was followed by a GLP validation which demonstrated excellent intra- and inter-day accuracy and precision for the quantitation of eszopiclone in human plasma at 1.00–100 ng/mL range using LC/MS/MS technology. This method was utilized to support multiple clinic bioequivalence studies.     

Determination of the antidepressant fluoxetine in human plasma by LC with UV detection

A selective and sensitive isocratic high-performance liquid chromatographic (HPLC) method was developed for the quantitative analysis of low concentrations of fluoxetine (FLX) in human plasma, with ultra-violet detection at 226 nm. A reversed-phase column, LiChrospher® 60 RP-Select B (125×3 mm i.d., 5 μm) (Merck), was used to resolve FLX and diazepam (DZP) (internal standard) from endogenous matrix interferences. FLX was isolated from plasma by liquid-liquid extraction. Two identical HPLC systems were used, both validated under the same study conditions. Each chromatographic separation was completed in 30 min and the results showed a mean relative recovery of 101 and 99.3% and an overall precision (RSD%) of 4.78 and 6.09 for each HPLC system. The standard curve was linear for FLX concentrations over the range of 5.00–50.0 ng ml⁻¹ (R=0.997 and 0.998).The limit of quantitation of FLX was 5 ng ml⁻¹ for both HPLC systems. The method described was applied to the analysis of plasma samples obtained from healthy subjects treated with one single oral dose of 40 mg of fluoxetine.     

Liquid chromatographic analysis of physostigmine salicylate and its degradation products

A simple stability-indicating HPLC assay has been developed for physostigmine salicylate, capable of following its degradation. A 250×5 mm i.d. column packed with 10 μm Bondapak C₁₈ was used, with a mobile phase of acetonitrile–ammonium acetate (pH 6.0; 0.1 M) (50:50, v/v) and flow rate 1.2 ml min⁻¹. All peaks are eluted in <10 min and the method has good precision. The optimum wavelength for detection of degradation products is 305 nm. Application of the assay for a commercial preparation of physostigmine salicylate for injection is presented.     

Identification and characterization of stressed degradation products of prulifloxacin using LC-ESI-MS/Q-TOF, MSn experiments: development of a validated specific stability-indicating LC-MS method

A rapid, specific and novel gradient LC-MS method has been developed and validated for the identification and characterization of stressed degradation products (DPs) of prulifloxacin (PF) using liquid chromatography combined with quadrupole time-of-flight electrospray ionization tandem mass spectrometry (LC/Q-TOF-ESI-MS/MS). PF was subjected to hydrolytic (acidic, alkaline and neutral), oxidation, photolytic and thermal stress, as per ICH guidelines Q1A (R2). The drug showed extensive degradation in hydrolytic and oxidative, while it was stable to thermal and photolytic stress conditions. In total, 13 DPs were formed and the chromatographic separation of drug and its DPs was achieved on a C-18 column (4.6 × 250 mm, 5 μm) using gradient elution method. All the DPs have been identified and characterized using MSⁿ experiments and accurate mass measurements. The LC-MS method was validated with respect to specificity, linearity, accuracy, precision and robustness.     

液相色谱-串联质谱法测定人血浆中劳拉西泮的浓度及其在生物等效性研究中的应用

目的建立LC/MS/MS法测定人血浆中劳拉西泮含量的方法,研究其片剂生物等效性。方法取血浆样品0.3mL,加入内标地西泮乙腈溶液0.6mL,涡流混合5min,高速离心15min,取上清液20μL进样,流动相:0.04%甲酸-乙腈(35∶65,V/V);流速:0.2mL/min;ZORBAXEclipseXDB-C18(2.1mm×100mm,3.5μm)。采用电喷雾离子源三级四极杆串联质谱,以选择反应监测(SRM)方式进行检测。用于定量分析的离子反应分别为m/z321→275(劳拉西泮)和m/z285→193(内标:地西泮)。结果劳拉西泮线性范围为0.71~71.33ng·mL-1,定量限为0.71ng·mL-1,三种浓度的相对回收率为108.8%~112.3%,日内、日间RSD均小于4.1%(n=5)。结论本法专属、灵敏、快速,适用于劳拉西泮的生物等效性研究。     

The first occurrence of the cyanobacterial alkaloid toxin cylindrospermopsin in the Czech Republic as determined by immunochemical and LC/MS methods

Cylindrospermopsin (CYN) is a newly emerging carcinogenic alkaloid originally identified in tropical cyanobacteria Cylindrospermopsis raciborskii. Some recent studies reported production of this toxin also by other cyanobacteria in European countries. Here we report comparison of the immunochemical ELISA determination with the liquid chromatography/mass spectrometry (LC/MS) method for CYN analyses in the samples from the Czech Republic, Central Europe. We have analysed 56 samples of raw lake waters collected from 32 localities. CYN was found at 3 localities with Aphanizomenon sp. sub-dominated water blooms. Results of the ELISA and LC/MS showed good qualitative agreement. However, concentrations determined by ELISA (0.4-4 μg/L) were systematically higher than concentrations determined by LC/MS (0.01-0.3 μg/L). Differences between methods could be attributed to matrix effects (both in ELISA and LC/MS) or ELISA cross-reactivity with other unidentified derivatives of CYN. Our study demonstrates for the first time occurrence of CYN in the Central Europe. With respect to its suspected carcinogenicity, further research on distribution, concentrations and risks of this cyanobacterial toxin is needed.     

Determination of degradation products of squalamine lactate using LC/MS

Heat, acid and base stress methods were applied to study the stability of squalamine lactate. Liquid chromatography coupled with mass spectrometry was used to analyze the degraded samples and tentative structural identifications were assigned based on their molecular weight measurements, reactivity and MS/MS fragmentation. Solid squalamine lactate generated a new amide, namely lactyl squalamide, when heated to 80 degrees C. Chemical structure for this new compound has been established by NMR and MS data interpretation and confirmed by direct comparison between the degradant and the synthesized compound. Squalamine lactate in pH 4 acetate buffer solution produced more degradants under stressed conditions. These degradants are formed due to the loss of the sulfate functionality. Squalamine lactate is stable in refrigerated conditions as well as in basic solution.     

液相色谱-串联质谱法测定老年人血浆中石杉碱甲的浓度

目的建立测定老年人血浆中石杉碱甲的液相色谱-串联质谱方法。方法在血浆中加入内标石杉碱乙,用乙腈直接沉淀蛋白法处理样品。采用SeQuant ZIC-HILIC(100mm×2.1mm I.D,3.5μm)色谱柱进行分离,柱温35℃;流动相为含5 mmol·L~(-1)甲酸铵0.1%甲酸水溶液-乙腈(35:65,V/V),流速0.3 mL·min~(-1),柱温35℃,梯度洗脱,进样体积5μL;正离子多反应检测(MRM),离子通道分别为m/z 243.2→210.2(石杉碱甲),m/z 257.2→198.6(石杉碱乙)。结果石杉碱甲线性范围0.05～10μg·L~(-1)(r>0.999),定量下限0.05μg·L~(-1),提取回收率在81.0%～95.4%,批内、批间精密度RSD均小于8%,内标校正基质因子在2.11～2.28。主要药动学参数t_(max)为(2.2±0.7)h,ρ_(max)为(0.9±0.2)μg·L~(-1),t_(1/2)为(14.1±2.0)h,AUC_(0-∞)为(15.3±4.5)μg·h·L~(-1)。结论本方法操作简便、特异性强、灵敏度高,适用于石杉碱甲在老年人中的药动学研究。     

Identification of imatinib mesylate degradation products obtained under stress conditions

In this paper, the decomposition of imatinib mesylate (ImM) under hydrolytic (neutral, acidic, alkaline), oxidative and photolytic conditions was studied. The imatinib mesylate is practically photostable and stable under neutral conditions. The main degradation products under acidic and alkaline conditions are compounds: 4-methyl-N³-(4-pyridin-3-yl-pyrimidyn-2-yl)-benzene-1,3-diamine (2) and 4-(4-methyl-piperazin-1-ylmethyl)-benzoic acid (3). The main degradation products under oxidation conditions, i.e. 4-[(4-methyl-4-oxido-piperazin-1-yl)-methyl]-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)-phenyl]-benzamide (6), 4-[(4-methyl-1-oxido-piperazin-1-yl)-methyl]-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)-phenyl]-benzamide (7) and 4-[(4-methyl-1,4-dioxido-piperazin-1-yl)-methyl]-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)-phenyl]-benzamide (8), were isolated from the reaction mixtures and identified by the HPLC, ¹H NMR and MS techniques. During stress study the suitability of the proposed HPLC method to control purity of the samples was verified.     

土霉素加速破坏降解产物的LC-MS研究

目的建立土霉素及降解产物的LC—MS方法，分析土霉素在各种加速破坏条件下的降解产物，探讨其可能的降解途径。方法通过加速实验制备实验样品，利用分析柱，经柱后分流，电喷雾电离和选择性离子检测，分析降解产物和降解途径。结果在弱酸、强酸、强碱、加热和氧化5种破坏条件下．土霉素可以产生多种降解产物，其主要降解产物为4-差向土霉素(4-epi-oxytetracycline EOTC)、脱水土霉素(anhydrooxytetracycline AOTC),α-原土霉素(α—Apo—oxytetracycline α—APOTC)、β-原土霉素(β-Apo—oxytetracycline β-APOTC)、异土霉素(isooxytetracycline IOTC)。结论建立的LC—MS方法可用于该类降解产物及降解途径研究，所确定的降解产物及降解途径为该品种质量控制和稳定性研究提供了重要依据。     

用LC/MS法测定人血浆及尿中对乙酰氨基酚和帕马溴的含量

目的：建立LC/MS法测定人血浆及尿中对乙酰氨基酚和帕马溴含量。方法：采用AgilentSB-C18色谱柱,血浆中测定以咖啡酸为内标,尿中测定以青藤碱为内标,流动相为乙腈：0.05%甲酸溶液（10：90）,流速0.3ml/min。用于定量分析离子对：对乙酰氨基酚质荷比（m/z）152.1,帕马溴m/z259.1,咖啡酸m/z181.1,青藤碱m/z330.9。结果：血浆中对乙酰氨基酚浓度在0.051～20.24μg/ml范围内线性关系良好,帕马溴浓度在0.025～10.10μg/ml范围内线性关系良好,对乙酰氨基酚和帕马溴日内、日间精密度均〈15.0%,对乙酰氨基酚及帕马溴相对回收率分别为86.4%～107.4%和95.7%～107.0%。尿中对乙酰氨基酚浓度在2.825～1415μg/ml范围内线性关系良好,帕马溴浓度在2.65～1325μg/ml范围内线性关系良好,对乙酰氨基酚和帕马溴日内和日间精密度均〈15.0%,对乙酰氨基酚及帕马溴相对回收率分别为85.3%～109.1%和98.3%～101.6%。结论：本研究建立的两个方法快速、灵敏、准确,适用于复方氨酚帕马溴片的药动学研究。     

Rapid and sensitive simultaneous determination of ezetimibe and simvastatin from their combination drug products by monolithic silica high-performance liquid chromatographic column

A simple, precise and rapid high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of ezetimibe (EZE) and simvastatin (SIM) from their combination drug products. The applicability of monolithic LC phases in the field of quantitative analysis has been evaluated. The existing method with UV detection set at 240 nm was successfully transferred from a conventional silica column to a 10 cm × 4.6 mm i.d. monolithic silica column. By simply increasing the mobile phase flow rate, run time was about five-fold reduced and the consumption of mobile phase was about two-fold decreased, while the chromatographic resolution of the analytes remain unaffected. Ranitidine (RAN) was used as internal standard to guarantee a high level of quantitative performance. The method used a mobile phase consisted of acetonitrile–ammonium acetate (50 mM pH 5.0) (65:35, v/v). It was validated with respect to system suitability, specificity, limit of quantitation (LOQ) and detection (LOD), linearity, precision, accuracy, and recovery, respectively. The described method was linear over the range of 40–1200 ng ml⁻¹ (r = 0.999) for both drugs. The LOD for EZE and SIM were 13.2 ± 0.4029 and 13.3 ± 0.4772 ng ml⁻¹, respectively. The LOQ were found to be 39.9 ± 1.221 and 39.5 ± 1.446 ng ml⁻¹ for EZE and SIM, respectively. The method is fast (less than 2.0 min) and is suitable for high-throughput analysis of the drug and ones can analyze 700 samples per working day, facilitating the processing of large-number batch samples.