Enantioselective determination of the novel antidepressant mirtazapine and its active demethylated metabolite in human plasma by means of capillary electrophoresis

Mirtazapine is a recent noradrenergic and specific serotonergic antidepressant drug. A capillary electrophoretic method has been developed for the enantioseparation and analysis of mirtazapine and its main active metabolite, N-desmethylmirtazapine, in human plasma. For method optimisation several experimental parameters were investigated, such as type and concentration of the chiral selector, buffer pH and capillary temperature. Baseline enantioseparation of the analytes was achieved in 2.5 min in a fused silica capillary (50 microm i.d.; 48.5 cm total length; 8.5 cm effective length) using carboxymethyl-beta-cyclodextrin, dissolved in a background electrolyte consisting of 50 mM phosphate buffer at pH 2.5, as the chiral selector. UV detection was set at 205 nm. A careful pre-treatment of plasma samples was developed, using solid-phase extraction with hydrophilic-lipophilic balance cartridges (60 mg, 3 mL), eluting the sample with methanol, then concentrating it 37.5 times before injection. Extraction yield values are very satisfactory, being the average 89% for mirtazapine and 73% for N-desmethylmirtazapine. Application of the method to some human plasma samples has given satisfactory results.     

Determination of chloramphenicol in biological matrices by solid‐phase membrane micro‐tip extraction and capillary electrophoresis

Solid‐phase membrane micro‐tip extraction (SPMMTE) and capillary electrophoresis (CE) methods were developed and validated for analysis of chloramphenicol in human plasma and urine samples. Iron composite nanoparticles were prepared using green technology. CE was carried out using a silica capillary (60 cm × 50 μm i.d.), phosphate buffer (50 mm , 8.0 pH)–acetonitrile (95:5, v/v) as the background electrolyte, 10 kV voltage, 280 nm detection, 20 s injection time and 27 ± 1°C temperature. Frusemide was used as an internal standard. The values of migration time, electrophoretic mobility, electrophoretic velocity and theoretical plates of chloramphenicol were 12.254 min, 4.44 × 10, 7.41 × 10 and 11,227. The limits of detection and quantitation of chloramphenicol were 0.1 and 1.0 μg/mL. Recovery of chloramphenicol in the standard solution was 95%. Solid‐phase membrane micro‐tip extraction and capillary electrophoresis methods may be used to analyze chloramphenicol in human plasma and urine samples of any patient.     

Capillary electrophoretic chiral separation of hydroxychloroquine and its metabolites in the microsomal fraction of liver homogenates

A rapid, selective, and low-cost chiral capillary electrophoretic method was developed for the simultaneous analysis of hydroxychloroquine (HCQ) and its three chiral metabolites: desethylchloroquine (DCQ), desethylhydroxychloroquine (DHCQ), and bisdesethylchloroquine (BDCQ) in the microsomal fraction of liver homogenates. After liquid-liquid extraction using toluene as extracting solvent, the drug and metabolites were resolved on a fused-silica capillary (50 microm ID, 50 cm total length, and 42 cm effective length), using 100 mmol/L of Tris/phosphate buffer, pH 9.0 containing 1% w/v sulfated-beta-CD and 30 mg/mL hydroxypropyl-beta-CD. Detection was carried out at 220 nm. The extraction procedure was efficient in removing endogenous interferents, and low values (相似文献   

Analysis of metformin dosage formulations by capillary electrophoresis at nano scale detection

An inexpensive, rapid and reproducible capillary electrophoretic method has been developed and validated for the determination of metformin in pharmaceutical preparations. The method was developed utilizing a fused silica capillary (60 cm x 50 microm I.D.), phosphate buffer (50 mM, 3.0 pH)-acetonitrile (95:5, v/v) as background electrolyte (BGE), 20 kV applied voltage with UV detection at 254 nm and at a working temperature of 23 +/- 1 degrees C. Linearity was observed in the concentration range from 100 ng/L to 5 microg/L, with a correlation coefficient (R2) of 0.9998. The limits of detection and quantification achieved were 60 and 100 ng/mL, respectively. The recovery of metformin from pharmaceutical preparations was 99.1%. These validation parameters demonstrate the precision of the method and its suitability for the determination of metformin in pharmaceutical tablet formulations.     

Analysis of the aconitine alkaloids in traditional Chinese medicines by nonaqueous capillary electrophoresis using a new recording mode

The determination of three aconitine alkaloids (hypaconitine, aconitine, mesaconitine) in five traditional Chinese medicines including two Tibetan medicines, Chuanwu, Caowu, Fuzi, Aconitum Tanguticum Maxim and Aconitum Gymnandrum Maxim by non-aqueous capillary electrophoresis using a new recording mode is described. The dissociation constants of aconitine, mesaconitine and hypaconitine have also been determined by CZE and were 7.71, 6.60 and 6.25, respectively. The separation was achieved by optimizing the applied voltage, the pH and the concentration of the buffer. The electrophoretic medium was 20 mM borax-70% (v/v) methanol (pH 8.5) and an uncoated capillary (50 cm x 75 microm i.d.) was used. Detection was carried out with a UV monitor at 214 nm. The total time for separation and determination was under 13 min.     

电中性物质的毛细管胶束电动色谱

在自制的高效毛细管电泳装置上,使用内径为0.05毫米,长为450毫米的熔融石英毛细管,十二烷基硫酸钠胶束溶液,254nm检测波长,进行了电中性化合物的毛细管胶束电动色谱研究。并将乙醇-水混合溶剂引入体系,成功地进行了多环芳烃的分离。考察了电场强度,SDS浓度及乙醇含量对柱效的影响。     

Determination of the beta-blocker atenolol in plasma by capillary zone electrophoresis

A capillary zone electrophoretic method was optimised for the determination of the beta-blocker atenolol in plasma. Separation was performed in an uncoated silica capillary of 58.5 cm (effective length 50 cm) x 75 microm I.D., and detection was at 194 nm. The effects of the buffer (concentration and pH), the injection time, the voltage applied and the plasma clean-up procedure were studied. The determination of atenolol was achieved in less than 3 min, using an electrolyte of 50 mM H3BO3-50 mM Na2B4O7 (50:50, v/v) pH 9, injected hydrodynamically for 4 s at 50 mbar and applying a voltage of +25 kV. This method was applied to the determination of atenolol in plasma of nine hypertensive patients (male and female, aged from 39 to 73 years). Atenolol concentrations found vary from 30 to 585 ng/ml.     

Continuous capillary electrophoresis with flow injection and its application for determination of Ephedrine and Pseudo-ephedrine in Chinese medicinal preparations

This article presents a new, simple and rapid continuous separation method by combination of flow injection with capillary electrophoresis designed for the analysis of basic traditional Chinese medicines. The device was produced using commercial capillary and components readily available in analytical laboratory. In double-T configuration, the designed horizontal separation channel was 25 microm i.d. x 146 mm length (an effective separation length of 93 mm) quartz capillary, with two vertical elicitation arms produced from 0.5 mm i.d. pump tubing. The capillary was embedded in a 40 x 20 x 3 mm organic glass base. Using the double-T configuration, continuous introduction of a series of samples was achieved. More than 3.00 resolution for ephedrine and pseudo-ephedrine were obtained using 100 mm borate buffer (pH 9.80) within 8 min in 25 microm separation channel with an electrical field strength of 137 V/cm (UV detection at 215 nm). The linear calibration range was 50-1500 microg/mL (ephedrine, r = 0.9982; pseudo-ephedrine, r = 0.9990) for both analytes. The limits of detection were 2.65 micro g/mL for ephedrine and 2.92 microg/mL for pseudo-ephedrine. In this device, the contents of ephedrine and pseudo-ephedrine in five Chinese medicinal preparations were determined with RSDs (n = 5) in range 1.16-4.51% and recoveries in range 90.4-114.6%.     

Rapid electrophoretic monitoring of the anaesthetic ketamine and its metabolite norketamine in rat blood using a contactless conductivity detector to study the pharmacokinetics

A method of capillary electrophoresis with contactless conductivity detection has been developed for non‐enantioselective monitoring the anaesthetic ketamine and its main metabolite norketamine. The separation is performed in a 15 μm capillary with an overall length of 31.5 cm and length to detector of 18 cm; inner surface of the capillary is covered with a commercial coating solution to reduce the electroosmotic flow. In an optimised background electrolyte with composition 2 M acetic acid + 1% v/v coating solution under application of a high voltage of 30 kV, the migration time is 97.1 s for ketamine and 95.8 s for norketamine, with an electrophoretic resolution of 1.2. The attained detection limit was 83 ng/mL (0.3 μmol/L) for ketamine and 75 ng/mL (0.3 μmol/L) for norketamine; the number of theoretic plates for separation of an equimolar model mixture with a concentration of 2 μg/mL was 683 500 plates/m for ketamine and 695 400 plates/m for norketamine. Laboratory preparation of rat blood plasma is based on mixing 10 μL of plasma with 30 μL of acidified acetonitrile, followed by centrifugation. A pharmacokinetic study demonstrated an exponential decrease in the plasma concentration of ketamine after intravenous application and much slower kinetics for intraperitoneal application.     

毛细管电泳法快速检测消毒剂中的醋酸氯己定

建立了消毒剂中活性成分醋酸氯己定(又名:醋酸洗必泰)的毛细管电泳快速检测法。采用15 mmol/L磷酸盐-乙腈( 体积比为60∶40)缓冲体系,将醋酸氯己定在50 cm×75 μm i.d.的石英毛细管柱中进行电泳分离,电泳电压为15 kV,检 测波长为254 nm。同时,对毛细管电泳分析醋酸氯己定的条件(如缓冲液的种类、pH值、浓度及电泳电压等)进行了优化 。用该方法对消毒剂样品进行测定,在4 min内可完成分析。醋酸氯己定在质量浓度为0.01～0.10 g/L时线性良好,检测 限为0.004 mg/L,吸光度值的相对标准偏差为3.97%,迁移时间的相对标准偏差为2.99%,样品加标回收率为91.4%～116.6%。将该方法 与高效液相色谱法进行比较,两种方法测定结果的相对误差≤4%。所建立的检测醋酸氯己定含量的毛细管区带电泳法简单 、快速,适用于消毒剂样品的测定。     

胶束电动毛细管色谱法测定消糖灵中的优降糖

 以甲氧苄氨嘧啶为内标,采用胶束电动毛细管色谱法分离测定了新药消糖灵中的优降糖。电泳条件：以25 mmol/L硼砂-30 mmol/L十二烷基硫酸钠（pH 9.0）为电泳介质,未涂层石英毛细管（50 μm i.d.×39.5 cm,有效分离长度34.8 cm）为分离通道,压力进样(68.95 kPa.s),17 kV恒压电泳（28 ℃）,检测波长228 nm。优降糖在14 min内与其他成分得到很好分离,且质量浓度为25 mg/L～275 mg/L时,优降糖可进行定量分析,加标回收率为(100.6±1.4)%。方法简便、快速,结果准确,重现性好,可用于优降糖复方制剂的质量控制。     

Enantioselective analysis of primaquine and its impurity quinocide by capillary electrophoresis

A capillary electrophoretic (CE) method for the baseline separation of the enantiomers of primaquine diphosphate (PQ) and quinocide (QC) (a major contaminant) in pharmaceutical formulations is proposed. Both components were separated under the following conditions: 50 mm tris phosphate buffer (pH 3.0) containing 15 mm hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) as background electrolyte; applied voltage, 16 kV; capillary temperature, 25 degrees C; detection wavelength, 254 nm; hydrostatic injection, 10 s. The separations were conducted using a 35 cm length and 50 microm i.d. uncoated fused silica capillary column. Under the optimized conditions, the components were successfully separated in about 5 min. Intraday precision of migration time and corrected peak areas when expressed as relative standard deviation ranged from 0.17 to 0.45 and 2.60 to 3.94%, respectively, while the interday precision ranged from 2.59 to 4.20 and 3.15 to 4.21%, respectively. After the validation exercise, the proposed method was applied for the determination of QC impurity in PQ formulations.     

高效毛细管电泳法同时测定多种神经肽物质的研究

用０．１ｍｏｌ／ＬｐＨ２．７磷酸缓冲液,在５０μｍ×６０ｃｍ熔融石英毛细管柱中、１２ｋＶ电位下对ＳＰ、ＮＫＡ、ＮＴ、ＳＳ及ＳＰ－片段等神经肽物质进行分离测定,对缓冲液及其ｐＨ值的选择进行研究。结果表明,高效毛细管电泳法是分析肽物质较为理想的方法。     

Enantiomeric determination of praziquantel and its main metabolite trans-4-hydroxypraziquantel in human plasma by cyclodextrin-modified micellar electrokinetic chromatography

A capillary electrophoresis method for the simultaneous quantitation of praziquantel and its main metabolite trans-4-hydroxypraziquantel enantiomers in human plasma was developed and validated using cyclodextrin-modified micellar electrokinetic chromatography. Sample clean-up involved a single-step liquid-liquid extraction of plasma with toluene after the addition of NaCl. The complete enantioselective analysis was obtained in less than 7 min using 2% w/v sulfated beta-cyclodextrin as chiral selector and 20 mmol/L sodium deoxycholate as surfactant, in 20 mmol/L sodium borate buffer, pH 10. A 50 microm x 42 cm uncoated fused-silica capillary was used for the analysis, performed at a voltage of 18 kV and at 20 degrees C. The calibration curves were linear over the 125-625 ng/mL concentration range. The mean recoveries for praziquantel and trans-4-hydroxypraziquantel were up to 96 and 71%, respectively, with good precision. All four enantiomers were quantified at two concentration levels (200 and 600 ng/mL) with precision and accuracy below 15%. The quantitation limit was 50 ng/mL for (-)-(R)- and (+)-(S)-praziquantel and 62.5 ng/mL for (-)-(R)- and (+)-(S)-trans-4-hydroxypraziquantel, using 1 mL of human plasma.     

在线推扫富集-胶束电动毛细管色谱检测旋覆花素中和大鼠血浆中的旋覆花内酯

采用熔融石英毛细管,以含有50 mmol/L 十二烷基硫酸钠的50 mmol/L硼酸盐缓冲液为电极缓冲液,以10 mmol/L硼酸盐缓冲液为上样缓冲液,经过对分离条件的优化,成功地建立了胶束电动毛细管色谱结合在线sweeping(推扫)富集技术检测中性脂溶性物质旋覆花内酯(acetylbritannilactone,ABL)的实验方法。所建方法的批内、批间测定值的相对标准偏差均小于5%,灵敏度为0.005 g/L,回收率大于92%;被检测样品的含量与峰面积呈良好的线性关系,相关系数为0.9975。用所建立的方法检测了旋覆花素中ABL的含量及其在体内的动态变化,结果表明胶束电动毛细管色谱结合在线sweeping样品富集技术可显著提高检测的灵敏度。该方法具有操作简单、进样量小(nL级)、检测速度快等特点,弥补了毛细管电泳在测定痕量组分方面的不足。     

Iron protoporphyrin-modified monolithic support for on-line preconcentration of angiotensin prior to CE analysis

An on-line preconcentration method using a polymeric monolithic support is proposed for the retention of the decapeptide angiotensin I and its subsequent analysis by CZE. Monolithic capillary columns were prepared in fused-silica (FS) capillaries of 150 microm id by ionizing radiation-initiated in situ polymerization and cross-linking of diethylene glycol dimethacrylate and glycidyl methacrylate, and chemically modified with iron protoporphyrin IX (Fe-ProP). Monolithic microcolumns (8 mm long) were coupled on-line to the inlet of the separation capillary (FS capillary, 75 microm id x10 cm from the inlet to the microcolumn and 27 cm from the microcolumn to the detector). Angiotensin I was released from the sorbent by a 50 mM sodium phosphate, pH 2.5/ACN, 75:25 v/v solution and then analyzed by CZE with UV absorption detection at 214 nm. The concentration LOQ (CLOQ) was 0.5 ng/mL. The Fe-ProP-derivatized monolithic microcolumn coupled to the separation capillary exhibited a high retention capacity for peptide angiotensin I, and showed as much as 10,000-fold improvement in concentration sensitivity.     

胶束电动毛细管色谱法分离左旋十八甲基炔诺酮、睾酮和孕酮

胶束电动毛细管色谱法（MECC）被用于左施十八甲基炔诺酮（LNC）、睾酮（T）和孕酮（P）的分离。电泳缓冲液中含一定量的乙腈或甲醇等有机添加剂时,可以改善分离。当乙睛体积分数为0～15％时,样品的迁移时间tm随着乙腈体积分数的增加而增加,但当已腈体积分数大于15％时,样品的tm随乙腈体积分数的增加反而减少。如采用20mmol／L的2,6-二甲基-β-环糊精（DM-β-CD）作添加剂,不仅可提高分高度,而且能缩短分析时间,实现最佳分离。     

高效液相色谱法和毛细管电泳法测定甘草制品中甘草酸的含量

分别用高效液相色谱法（ＨＰＬＣ）、毛细管区带电泳法（ＣＺＥ）、胶束电动毛细管色谱法（ＭＥＣＣ）测定了甘草制品中甘草酸的含量。对ＨＰＬＣ,ＣＺＥ,ＭＥＣＣ的分析条件作了一些选择实验,结果表明ＭＥＣＣ法与ＨＰＬＣ法分析数据接近、比较准确,而且前者比ＨＰＬＣ法分离效率高、溶剂用量少,是一种很有发展潜力的分析方法。     

Overcoming interference of plasma phospholipids using HybridSPE for the determination of trimetazidine by UPLC–MS/MS

An improved, precise and reliable ultra‐performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method has been developed for the quantification of trimetazidine, using trimetazidine‐d8 as the internal standard (IS). Interference owing to plasma phospholipids during sample preparation was overcome using a hybrid solid‐phase extraction–phospholipid ultra cartridge. The mean extraction recovery of trimetazidine (98.66%) and trimetazidine‐d8 (97.63%) from spiked plasma was consistent and reproducible. Chromatographic analysis was performed on a UPLC Ethylene Bridged Hybrid (BEH) C18 (50 × 2.1 mm, 1.7 μm) column with isocratic elution using acetonitrile–5 mm ammonium formate, pH 3.5 (40:60, v/v) as the mobile phase. The parent → product ion transitions for trimetazidine (m/z 267.1 → 181.1) and trimetazidine‐d8 (m/z 275.2 → 181.1) were monitored on a triple quadrupole mass spectrometer with electrospray ionization functioning in the positive multiple reaction monitoring mode. The linearity of the method was established in the concentration range of 0.05–100 ng/mL for trimetazidine. The intra‐batch and inter‐batch accuracy and precision (CV) were 97.3–103.1 and 1.7–5.3%, respectively. Qualitative and quantitative assessment of matrix effect showed no interference of endogenous/exogenous components. The developed method was used to measure plasma trimetazidine concentration for a bioequivalence study with 12 healthy subjects.     

胶束电动毛细管色谱分析间接紫外吸收检测人体血小板活化因子

研究了人体血小板活化因子中1-O-十六烷基乙酰甘油磷酰胆碱与1-O-八烷基乙酰甘油磷酰胆碱的胶束电动毛细管色谱分离条件与间接紫外吸收检测条件。首次采用高效毛细管电泳法成功地分析了人体血小板活化因子中两种主要磷酰胆碱的含量。