Simultaneous Determination of High-Density Lipoprotein,Very Low-Density Lipoprotein and Low-Density Lipoprotein Subclass in Human Serum by Microchip CE

Lipoproteins, especially high-density lipoproteins (HDL), very low-density lipoproteins (VLDL) and small, dense low-density lipoprotein (sdLDL), are believed to play an important role in the development of atherosclerosis. In this work, a simple, selective and sensitive method for the simultaneous monitoring of these lipoproteins in human serum using microchip capillary electrophoresis was developed. Gold nanoparticles were used as an additive to the running buffer to obtain the absolute separation of the lipoproteins. Under optimised conditions, the linear ranges of large buoyant low-density lipoproteins, sdLDL, VLDL and HDL were 10–800, 10–800, 40–1,000 and 20–800 μg L⁻¹, and their limits of detection were 5, 5, 15 and 8 μg L⁻¹, respectively. The intraassay and interassay relative standard deviation of lipoprotein peak areas were in the range of 3.8–7.4%. For practical application, variations in the serum lipoprotein of coronary heart disease patients were monitored by microchip-based CE. The results showed that the method was applicable for routine clinical use and allowed the rapid detection of different lipoprotein classes as well as their subclasses, thus greatly improving the analysis of atherosclerotic risk factors.

     

微流控芯片电泳分离血清中小而密低密度脂蛋白的研究

应用微流控芯片电泳,以40 mmol/L Tricine(pH9.8)作为电泳缓冲体系,十二烷基硫酸钠(SDS)作为添加剂(0.1 mmol/L SDS样品溶液,0.02 mmol/L SDS分离缓冲液),分离血清小而密低密度脂蛋白(sdLDL)。研究荧光染料硝基苯并噁二唑-C6-酰基鞘胺醇(NBD C6-ceramide)与脂蛋白结合的特异性、饱和性以及血清保存和检测时间对脂蛋白电泳行为的影响;探讨SDS有效降低蛋白吸附,提高血清脂蛋白分辨率的作用。冠心病(CHD)组sdLDL检出率(75%)显著高于对照组(6%,P<0.01)。该法具有简易、快速、高效等优点,可望成为CHD危险性评估的常规分析手段。     

CE Determination of Droperidol in Tablets and Human Serum

A capillary electrophoretic method was described for the determination of droperidol in pharmaceutical tablets and human serum. Droperidol and internal standard, lansoprazole, were separated on an uncoated fused-silica capillary using a run buffer containing borate (10 mM; pH 9.3) and aqueous methanol (20%, υ/υ). The signals were detected at 210 nm. The migration times for droperidol and internal standard were 2.1 and 2.9 min, respectively. The method has been validated in the range of 2.2 × 10^?5 ? 7.8 × 10^?5 M and applied to both tablets and human serum with good repeatability and no interference.     

Simultaneous Determination of Lidocaine, Proline and Lomefloxacin in Human Urine by CE with Electrochemiluminescence Detection

A new method was developed for the simultaneous determination of lidocaine, proline and lomefloxacin in human urine by capillary electrophoresis-electrochemiluminescence detection with Ru(bpy)₃ ²⁺. Conditions of the separation and detection were investigated and optimized. It was proved that 20 mM phosphate buffer at pH 6.7 could achieve the most favorable resolution, and the high sensitivity of detection was obtained by using the detection potential at 1.15 V and 5 mM Ru(bpy)₃ ²⁺–60 mM phosphate buffer at pH 7.6 in the detection reservoir. The detection limits were 0.02 μg mL⁻¹ for lidocaine, 0.03 μg mL⁻¹ for proline and 0.06 μg mL⁻¹ for lomefloxacin. Relative standard deviations of the ECL intensity and the migration time were 3.5 and 1.1% for 6 μg mL⁻¹ lidocaine, 3.2 and 1.0% for 6 μg mL⁻¹ proline and 3.7 and 1.2% for 6 μg mL⁻¹ lomefloxacin, respectively. A baseline separation for lidocaine, proline and lomefloxacin was achieved within 360 s. The developed method was successfully applied to determine the amounts of lidocaine, proline and lomefloxacin in human urine. The recovery and RSD were in the range of 93.3–97.2 and 3.8–4.9%, respectively.     

Simultaneous CE Determination of Captopril and Indapamide in Pharmaceuticals and Human Plasma

Capillary electrophoresis with UV photo diode-array detection was utilized to adopt a new method for the assay of captopril and indapamide in pharmaceuticals and human plasma. Electrophoretic conditions controlling the analysis were optimized to develop separation, sensitivity and rapidity. The optimum conditions obtained were 100 mM borate at pH 9.0, injection time 10.0 s, voltage 25 kV and column temperature 25 °C with detection at 220 nm. Relatively, wide dynamic ranges for captopril (1–100 mg L^?1) and indapamide (0.1–40 mg L^?1) were obtained. Also, the method recorded acceptable intra- and inter-day accuracy (89.8–97.9%) and precision (0.77–3.50%) in pharmaceutical formulations and human plasma. The sensitivity of the method was developed by the optimization and the preconcentration conducted for human plasma sample using liquid–liquid extraction. The limit of detection gained (0.075 and 0.045 mg L^?1 for captopril and indapamide, respectively) reached the level of both drugs possibly found in human plasma. The method is suitable to be applied in pharmaceutical industries for quality control and in clinical laboratories for therapeutic drug monitoring purposes.     

微流体芯片电泳技术对人血清蛋白的快速分离

通过微流体芯片电泳技术分离人血清蛋白,探讨了常见十字形微流体芯片上样品的电动进样与分离过程,分析了在十字芯片上的进样时间和电压设置对后续样品检测和定量的影响。采用的缓冲体系为:100mmol/L H3BO3,50mmol/L NaCl,5%Dextran(以NaOH调至pH 8.3),该缓冲液能够有效分离人血清蛋白中的白蛋白(Albumin)和4种球蛋白(α1-,α2-,β-,和γ-globulin),并且给出了它们在该缓冲体系中的淌度估算范围为5.15×10-5～47.2×10-5 cm2/(V.s)。在芯片上2min之内可以完成进样和分离,相比于常用的毛细管区带电泳,提高了分析速度。     

毛细管电泳法同时测定血清中的左旋多巴和甲基多巴

建立了毛细管电泳-紫外检测同时测定血清中左旋多巴和甲基多巴的方法。以40 mmol/L硼砂（pH 9.5）为分离缓 冲溶液,在3.45 kPa（0.5 psi）压力下进样7 s、分离电压22 kV、检测波长200 nm、温度25 ℃的条件下进行测定,两 种物质获得了较好的分离。甲基多巴和左旋多巴分别为1.0~64.0 mg/L和1.0~71.0 mg/L时与峰面积呈良好的线性关系, 线性相关系数分别为0.9998和0.9994,检出限分别为0.6和0.8 mg/L(以信噪比为3计)。将该法用于血清中甲基多巴和左 旋多巴的测定,回收率为82.8%~88.8%,相对标准偏差为2.10%~2.63%。     

Simultaneous Determination of Pyridoxine,Meclizine and Buclizine in Dosage Formulations and Human Serum by RP-LC

Rapid liquid chromatographic procedures for analytical quality control of pharmaceutical preparations and human serum containing antihistamine drugs, meclizine and buclizine alone or in combination with pyridoxine are proposed, using acetonitrile:water (80:20) as a mobile phase (pH adjusted to 2.6), methylparaben as internal standard and UV detection was made at 230 nm. The results obtained showed a good agreement with the declared content. The method shows good linearity in the range of 30–10,000 ng mL⁻¹ for pyridoxine and 25–10,000 ng mL⁻¹ for meclizine and buclizine serum concentrations with a correlation coefficient 0.9999 (inter- and intra-day CV < 3.91%). The recovery was >97.8%. The proposed method may be used for the quantitative analysis of meclizine and buclizine alone or in combination with pyridoxine from raw materials, in bulk drugs, dosage formulations and in serum.

     

Simultaneous Determination of Pyridoxine, Meclizine and Buclizine in Dosage Formulations and Human Serum by RP-LC

Rapid liquid chromatographic procedures for analytical quality control of pharmaceutical preparations and human serum containing antihistamine drugs, meclizine and buclizine alone or in combination with pyridoxine are proposed, using acetonitrile:water (80:20) as a mobile phase (pH adjusted to 2.6), methylparaben as internal standard and UV detection was made at 230 nm. The results obtained showed a good agreement with the declared content. The method shows good linearity in the range of 30–10,000 ng mL^?1 for pyridoxine and 25–10,000 ng mL^?1 for meclizine and buclizine serum concentrations with a correlation coefficient 0.9999 (inter- and intra-day CV < 3.91%). The recovery was >97.8%. The proposed method may be used for the quantitative analysis of meclizine and buclizine alone or in combination with pyridoxine from raw materials, in bulk drugs, dosage formulations and in serum.     

Simultaneous Determination of Abacavir,Efavirenz and Valganciclovir in Human Serum Samples by Isocratic HPLC-DAD Detection

A rapid, sensitive, and specific reverse phase high performance liquid chromatography with diode array detection procedure for the simultaneous determination of abacavir, efavirenz and valganciclovir in spiked human serum is described. Separation was performed on a 5 μm Waters Spherisorb column (250 × 4.6 mm ID) with acetonitrile: methanol:KH₂PO₄ (at pH 5.00) (40:20:40 v/v/v) isocratic elution at a flow rate of 1.0 mL min⁻¹. Calibration curves were constructed in the range of 50–30,000 ng mL⁻¹ for abacavir and efavirenz, and 10–30,000 ngmL⁻¹ for valganciclovir in serum samples. The limit of detection and limit of quantification concentrations of the HPLC method were 3.80 and 12.68 ng mL⁻¹ for abacavir, 2.61 and 8.69 ng mL⁻¹ for efavirenz, 1.30 and 4.32 ng mL⁻¹ for valganciclovir. The method has been applied, without any interference from excipients or endogenous substances, for the simultaneous determination of these three compounds in human serum.

     

Simultaneous Determination of Calcium and Magnesium in Human Blood Serum by Atomic Absorption Spectrophotometer

Abstract

Simultaneous determination of calcium and magnesium content in human blood serum has been reported as a routine clinical laboratory method, which is rapid, simple, and requires 50 δ of serum for complete analysis with triplicate runs. This is accomplished using a Model 1250 Varian Techtron Atomic Absorption Spectrophotometer with the stoichiometric nitrous oxide-acetylene flame of 0.2 cm red-cone height. Calcium and magnesium standards and also the serum specimens are prepared in aqueous medium containing 2000 ppm potassium chloride. Serum specimens are ultimately diluted to 1:100 fold. About 40–50 samples can be analyzed per hour of instrument operation, if standard solutions and diluted serum specimens are readily available.     

Analysis of Fatty Acid, and Lipoprotein, Metabolism by GC and HPLC: Effect of Low-Density Lipoprotein Apheresis

 Blood samples from 5 hyperlipidemic patients on chronic treatment with low-density lipoprotein (LDL) – apheresis were analysed for lipids and fatty acids in serum, lipoprotein fractions and erythrocyte membrane by capillary gas chromatography (GC), reversed-phase high-performance liquid chromatography (LC), spectrofluorometry and spectrophotometry. LDL-apheresis has been associated with significant changes of fatty acids metabolism in relation to triglyceride-rich lipoproteins. Oleic acid may exert its hypotriglyceridemic effect via VLDL, IDL, LDL and HDL fractions. Polyunsaturated fatty acids, associated with triglyceride metabolism via IDL or VLDL, are linoleic, gamma-linolenic and docosahexaenoic fatty acids. Received November 25, 1999. Revision September 5, 2000.     

Simultaneous Determination of Tranexamic Acid and Losartan Potassium in Dosage Formulations and Human Serum by RP-LC

Rapid liquid chromatographic procedure for analytical quality control of pharmaceutical preparations and human serum containing drugs, tranexamic acid together with losartan potassium are proposed, using acetonitrile: water (50:50), adjusting pH to 2.6 with phosphoric acid as a mobile phase, UV detection at 205 nm and propylparaben sodium was used as internal standard. The results obtained showed a good agreement with the declared contents. The method shows good linearity in the range of 40–10,000 ng mL^?1 for tranexamic acid serum concentrations with a correlation coefficient 0.9999 (inter- and intra-day CV <3.18) and in the range 5–10,000 ng mL^?1 for losartan potassium serum concentrations with a correlation coefficient 0.9999 (inter- and intra-day CV <3.61). The recovery was >97.8%. The proposed method may be used for the quantitative analysis of tranexamic acid and losartan potassium alone or in combination from raw materials, in bulk drugs, dosage formulations and in serum.     

Identification of Toxic 2,4-Decadienal in Oxidized, Low-Density Lipoprotein by Solid-Phase Microextraction

The oxidation of low-density lipoprotein (LDL) in vitro was studied by a combination of solid-phase microextraction and GC/MS. 2-trans,4-cis-2,4-Decadienal, which is strongly toxic in vitro, was detected as the early oxidation product. This compound is degraded further to hexanal and (by cyclization of 4-hydroxy-2-nonenal) to 2-pentylfuran.     

Simultaneous Determination of Four Major Iridoid Glycosides in Scrophularia ningpoensis by CE

A simple, accurate and reproducible capillary electrophoresis method with UV detection has been developed for the simultaneous determination of four iridoid glycosides, 6-O-methyl-catalpol, aucubin, harpagide, and harpagoside, in Scrophularia ningpoensis (Xuan-shen). The running buffer was 100 mM borate (pH 9.3) containing 20% methanol. Applied voltage was 20 kV and temperature was 25 °C. Diphylloside A was used as an internal standard (IS) and detection was at 200 nm. The effects on separation of buffer pH, buffer concentration, and organic modifiers were investigated. The extracts of S. ningpoensis were well separated within 45 min.     

Simultaneous Determination of Four Major Iridoid Glycosides in Scrophularia ningpoensis by CE

A simple, accurate and reproducible capillary electrophoresis method with UV detection has been developed for the simultaneous determination of four iridoid glycosides, 6-O-methyl-catalpol, aucubin, harpagide, and harpagoside, in Scrophularia ningpoensis (Xuan-shen). The running buffer was 100 mM borate (pH 9.3) containing 20% methanol. Applied voltage was 20 kV and temperature was 25 °C. Diphylloside A was used as an internal standard (IS) and detection was at 200 nm. The effects on separation of buffer pH, buffer concentration, and organic modifiers were investigated. The extracts of S. ningpoensis were well separated within 45 min.

     

FIA-双流通池同时测定血清中的锌和铜

本文以2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚(5-Br-PADAP)为显色剂,乳化剂OP为增溶剂,二乙基二硫代氨基甲酸钠(DDTC)为竞争络合剂,采用双流通池(一个流通池用来测定锌和铜络合物吸光度之和,另一个测定锌络合物吸光度),在一次进样中同时测定血清中锌和铜的含量。测定频率为45样/小时,测定铜和锌的线性范围分别为0.02~0.10μg/mL和0~0.12μg/mL。本法具有操作简单、快速、灵敏度高和易于推广等优点。     

Effective Separation and Simultaneous Determination of Four Fluoroquinolones in Milk by CE with SPE

A simple and sensitive capillary electrophoresis method with solid phase extraction was developed for the determination of sarafloxacin, ciprofloxacin, enrofloxacin and flumequine in milk. Solid-phase extraction with Oasis HLB cartridge column was used for the isolation of four fluoroquinolones in raw milk from a farm and fresh milk sample. Separation conditions of CE, including running buffer, voltage and temperature, were investigated and optimized. Baseline separation was achieved for the four fluoroquinolones under the developed conditions. Correlation coefficients greater than 0.9998 were obtained for all fluoroquinolones with a dynamic range from 1 up to 100 mg L^?1. The intra-day precision was less than 5%, and the inter-day precision was less than 6%. The method recoveries of four fluoroquinolones were in the range of 70.9–90.6%. The detection limits for sarafloxacin, ciprofloxacin, enrofloxacin and flumequine was 19.8, 15.2, 13.3 and 15.9 μg kg^?1, respectively, which allows positive detection of the fluoroquinolones at the targeted maximum residue levels in milk samples.     

Simultaneous Determination of Prazosin,Atorvastatin, Rosuvastatin and Simvastatin in API,Dosage Formulations and Human Serum by RP‐HPLC

Prazosin hydrochloride is the first developed selective antagonist for α₁ — adrenoceptors, which is used as antihypertensive agent. Statins are used in the treatment of various types of hypercholesterolemia. In the present paper a simple, specific an accurate RP‐HPLC method was developed and validated for the simultaneous determination of prazosin, atorvastatin, rosuvastatin and simvastatin in active and in dosage formulations. A nucleosil 100‐10, C‐18, 10μ column having 250 × 4.6 mm i.d. in isocratic mode, with mobile phase containing methanol:water:acetonitrile (70:20:10) adjusted to pH 2.5 ± 0.02 using orthophosphoric acid. The flow rate was 1 mLmin^?1 and effluents were monitored at 240 nm. The % recovery for all the drugs in formulations was found to be 94‐105%. The parameters such as accuracy (%RSD less than 2), precision (%RSD less than 2), linearity (>0.999) were found to be satisfactory. The presented method was applied without any interference of excepients for the determination of tablets. The proposed method due to its low LOQ, excellent accuracy, precision and selectivity could be used for routine quality control.