Quality evaluation of Guan‐Xin‐Ning injection based on fingerprint analysis and simultaneous separation and determination of seven bioactive constituents by capillary electrophoresis

The purpose of this study was to develop a comprehensive, rapid and practical capillary electrophoresis (CE) method for quality control (QC) of Guan‐Xin‐Ning (GXN) injection based on fingerprint analysis and simultaneous separation and determination of seven constituents. In fingerprint analysis, a capillary zone electrophoresis (CZE) method with a running buffer of 30 mM borate solution (pH 9.3) was established. Meanwhile, ten batches of samples were used to establish the fingerprint electropherogram and 34 common peaks were obtained within 20 min. The RSD of relative migration times (RMT) and relative peak areas (RPA) were less than 5%. In order to further evaluate the quality of GXN injection, a micellar electrokinetic chromatography (MEKC) method was developed for simultaneous separation and determination of bioactive constituents. Seven components reached baseline separation with a running buffer containing 35 mM SDS and 45 mM borate solution (pH 9.3). A good linearity was obtained with correlation coefficients from 0.9906 to 0.9997. The LOD and LOQ ranged from 0.12 to 1.50 μg/mL and from 0.40 to 4.90 μg/mL, respectively. The recoveries ranged between 99.0 and 104.4%. Therefore, it was concluded that the proposed method can be used for full‐scale quality analysis of GXN injection.     

Separation of 2-aminobenzoic acid-derivatized glycosaminoglycans and asparagine-linked glycans by capillary electrophoresis.

A capillary electrophoresis method was developed for the analysis of oligosaccharides combined with derivatization with 2-aminobenzoic acid. Glycosaminoglycan delta-disaccharides were effectively resolved on a fused-silica capillary tube using 150 mM borate, pH 8.5, as a running electrolyte solution. This analytical method was applied to the identification of glycosaminoglycan in combination with enzymatic digestion. The separation of N-glycans or glucose-oligomers was performed with a phosphate buffer containing polyethylene glycol or borate as an electrolyte solution. This method is expected to be useful in the determination of oligosaccharide structures in a glycoprotein.     

Combined use of ionic liquid and sulfobutylether‐β‐cyclodextrin as electrolyte additives for separation and determination of camptothecin alkaloids by CZE

This work reported that ionic liquid (IL) ([Bmim] [PF₆]) and sulfobutylether‐β‐CD (SBE‐β‐CD) were used as electrolyte additives for the separation and determination of camptothecin (CPT) alkaloids by CZE. Separation parameters such as the buffer type, pH, and concentration of the running buffer, the concentration of SBE‐β‐CD and IL, temperature, and separation voltage were all investigated in order to achieve the maximum possible resolution. The four analytes were baseline separated within 10 min in capillary at the separation voltage of 15 kV with a running buffer consisting of 20 mM borate buffer, 20 mM IL, and 100 mM SBE‐β‐CD at pH 9.0. Under such conditions, good linearity about two orders of magnitudes of peak areas was achieved for the investigated CPT alkaloids with the correlation coefficients ranging from 0.9946 to 0.9985. For all analytes, detection limits (S/N = 3) and quantitation limits (S/N = 10) range from 0.05 to 0.92 μg/mL and 0.17 to 3.06 μg/mL, respectively. The proposed method has not only been successfully applied to the separation and determination of CPT alkaloids but also showed that IL seemed to be a promising additive in CZE separation.     

Trace analysis of zotepine and its active metabolite in plasma by capillary electrophoresis with solid phase extraction and head-column field-amplified sample stacking

A sensitive high-performance capillary zone electrophoresis (CZE) with head-column field-amplified sample stacking (FASS) in binary system has been developed for the simultaneous determination of zotepine and its active metabolite, norzotepine, in human plasma. The separation of zotepine and norzotepine was performed using a background electrolyte consisting of 50% ethylene glycol-borate buffer (20mM, pH 8.0) solution with 20% methanol as the running buffer and on-column detection at 200 nm. Under the optimal FASS-CZE condition, good separation with high efficiency and short analysis time is achieved. Several parameters affecting the separation and sensitivity of the drug were studied, including sample matrix, pH and concentrations of the borate buffer, ethylene glycol and methanol. Using clozapine as an internal standard, the linear ranges of the method for the determination of zotepine and norzotepine in human plasma were over 3-100 ng/mL; the detection limits of zotepine and norzotepine in plasma were 2 and 1 ng/mL, respectively. A sample pretreatment by means of solid-phase extraction (SPE) with subsequent quantitation by FASS-CZE was used. The application of the proposed method for determination of zotepine and norzotepine in plasma collected after oral administration of 125 mg zotepine in one schizophrenic patient was demonstrated.     

Identification and determination of effective components in Euphrasia regelii by capillary zone electrophoresis

A capillary zone electrophoresis (CZE) method has been developed for simultaneous determination of eukovoside, cinnamic acid and ferulic acid in Euphrasia regelii for the first time. The electrophoresis buffer was 20 mmol/L sodium borate containing 10% (v/v) methanol (pH 8.50). The effects of concentration of borate and electrolyte pH on electrophoretic behavior and separation were studied. Regression equations revealed linear relationships (correlation coefficients 0.9995-0.9998) between the peak area of each analyte and the concentration. The levels of analytes in the different parts of Euphrasia regelii were easily determined with recoveries ranging from 95.5 to 104.2%.     

Separation and Migration Behavior of Dichlorophenols in β‐Cyclodextrin‐Modified Capillary Zone Electrophoresis

The separation and migration behavior of six isomeric dichlorophenols (DCPs) in cyclodextrin‐modified capillary zone electrophoresis (CD‐CZE) using a phosphate‐borate buffer at alkaline pH with β‐CD and hydroxypropyl‐β‐CD (HP‐β‐CD) as electrolyte modifiers were investigated. The influence of buffer pH and the concentration of β‐cyclodextrins were examined. The results indicate that baseline separation of six isomeric DCPs can be achieved with addition of β‐CD concentration in the range of 2.0‐10 mM or HP‐β‐CD concentration in the range of 4.0‐10 mM at pH 10.0. Binding constants of DCPs to β‐CDs were evaluated for a better understanding of the interaction of DCPs with β‐CDs.     

Application of carboxymethyl-beta-cyclodextrin as a chiral selector in capillary electrophoresis for enantiomer separation of selected neurotransmitters

The aim of this work was to optimize conditions for capillary electrophoresis separation of different neurotransmitters (serotonin, phenylalanine, dopamine, adrenaline, ephedrine, propranolol and DOPA) in a single run, including separation of existing enantiomers. As chiral selectors added to the borate background, electrolyte unsubstituted alpha-, beta- and -gamma-cyclodextrins (CDs), methyl-, dimethyl-, and trimethyl-substituted beta-CDs, and hydroxypropyl-substituted alpha-, beta- and gamma-CDs were examined. Also carboxymethyl-beta-CD and succinyl-beta-CD were used for this purpose. In addition to the kind and concentration of chiral selector, some other experimental factors also have been optimized, such as concentration of borate buffer, content of methanol, pH of electrolyte, method of sample introduction into the capillary and washing procedure between consecutive runs. The best results were obtained using 20 mM carboxymethyl-beta-CD in borate buffer of pH 7.5 as running electrolyte and hydrostatic injection. The obtained sensitivity of response (peak height) varied from 0.4 for adrenalines to 2.3 mAU mM(-1) for propranolols. The concentration detection limits (S/N=3) were in the range from 0.04 mM for propranolols to 0.2 mM for adrenalines. The resolution obtained in optimized conditions in a single run was from 0.75 for adrenalins and 1.0 for propranolols up to 2.0 for ephedrines. The developed method was employed for determination of these analytes in brain tissue extracts.     

毛细管区带电泳法测定卷烟中的生物碱

在磷酸缓冲体系中采用毛细管区带电泳法测定卷烟中的生物碱时,检测灵敏度低,分离度差。考察了卷烟中生物碱的 提取条件,分离缓冲溶液的类型、pH值和浓度,卷烟中生物碱测定方法的线性范围、检出限、重现性和回收率。结果发 现,当采用410 mmol/L的酒石酸溶液（pH 2.8）为缓冲体系时,卷烟中生物碱的检测灵敏度和分离度均有明显改善,烟碱 的线性范围为0.06~0.80 mg/L（其他生物碱为0.006~0.10 mg/L）,检出限为0.002~0.01 mg/L,相对标准偏差为2.2%~10%,回收率为87.6%~102%。     

Optimization for quantitative determination of four flavonoids in Epimedium by capillary zone electrophoresis coupled with diode array detection using central composite design

Herba Epimedii (family Berberidaceae), Ying-Yang-Huo in Chinese, is a famous Chinese herbal medicine. Flavonoids are thought to be the major active components in it. A capillary zone electrophoresis (CZE) separation were developed for simultaneous determination of four flavonoids including icariin, epimedin A, epimedin B and epimedin C in Epimedium. The effects of the experimental variables on CZE had been optimized by using central composite design (CCD). The best separation of four flavonoids could be obtained using 50 mM borate buffer (pH 10.0) containing 22% acetontrile as modifier, while separation voltage was 15 kV and temperature was at 25 degrees C. The method developed is accurate, simple and reproducible, which could be used for quality control of Epimedium and its medical preparations.     

Simultaneous determination of anthraquinones, their 8-beta-D-glucosides, and sennosides of Rhei Rhizoma by capillary electrophoresis

The simultaneous separation and determination of major anthraquinones (emodin, chrysophanol, rhein and their glucosides, aloe-emodin, sennoside A, and sennoside B) of Rhei Rhizoma were achieved by cyclodextrin modified capillary zone electrophoresis. The running electrolyte used in this method was 0.005 M alpha-cyclodextrin in 0.03 M borate buffer (pH 10.0) containing 20% acetonitrile, with an applied voltage of 20 kV.     

Rapid and sensitive determination of anthraquinones in Chinese herb using 1-butyl-3-methylimidazolium-based ionic liquid with beta-cyclodextrin as modifier in capillary zone electrophoresis

The present study reported the ionic liquid (IL) used as running electrolyte in capillary zone electrophoresis (CZE) with beta-cyclodextrin (beta-CD) as modifier for the separation of anthraquinones extract of Chinese herb Paedicalyx attopevensis Pierre ex Pitard. The optimum running electrolyte was 60 mM 1-butyl-3-methylimizolium tetrafluoroborate (1B-3MI-TFB) solution with 4.0 mM beta-CD. The pH was 10.00 and the applied voltage was 20 kV with detection at 254 nm. The present method was compared with others and the effect of Joule heating was discussed as well. More significantly, this method is the development of the ionic liquids application to the capillary electrophoresis.     

Determination of histamine and histidine by capillary zone electrophoresis with pre-column naphthalene-2,3-dicarboxaldehyde derivatization and fluorescence detection

A rapid and sensitive method was developed for the simultaneous determination of histamine and histidine by capillary zone electrophoresis with lamp-induced fluorescence detection. A fluoregenic derivatization reagent, naphthalene-2,3-dicarboxaldehyde (NDA) was successfully applied to label the histamine and histidine respectively. The derivatization conditions and separation parameters including pH and concentration of electrolyte and sample injection were optimized in detail. The optimal derivatization reaction was performed with 1.0 mM NDA, 20 mM NaCN, and 20 mM borate buffer, pH 9.1 for 15 min. The separation of NDA-tagged histamine and histidine could be achieved in less than 200 s with 40 mM phosphate buffer (pH 5.8) as the running buffer. The detection limits for histamine and histidine were 5.5 x 10(-9) and 3.8 x 10(-9) M, respectively (S/N = 3). The relative standard derivations for migration time and peak height of derivatives were less than 1.5 and 5.0%, respectively. The method was successfully applied to the analysis of histamine and histidine in the P815 mastocytoma cells and the beer samples.     

Determination of Four Anthraquinones in Xanthophytum Attopvensis Pierre by Capillary Zone Electrophoresis

A capillary zone electrophoresis (CZE) method has been developed for the simultaneous determination of four anthraquinones in Xanthophytum Attopvensis Pierre. The effects of several factors such as the pH, concentration of the running buffer and the separation voltage were investigated to find the optimum conditions. The optimum conditions were an electrolyte containing 15 mmol L^?1 borate, at pH 9.64 and 17.5 kV applied voltage. The four analytes were completely separated within 5 min. Regression equations gave linear relationships between the peak area of each analyte and the concentration. The recoveries ranged from 96.5% to 106.2%. The method was successfully used in the analysis of extracts from Xanthophytum Attopvensis Pierre with a relatively simple extraction procedure, and the assay results were satisfactory.     

Separation of phospholipids by capillary zone electrophoresis with indirect ultraviolet detection

A simple method for separation of different anionic and zwitterionic phospholipid classes by capillary zone electrophoresis (CZE), using indirect UV detection with adenosine monophosphate (AMP) as background electrolyte and the UV-absorbing additive, was successfully developed in this study. The separation conditions including apparent pH (pH*) of running buffer, concentration of AMP, organic solvent, applied voltage and capillary temperature were systematically optimized. The application of this method to human blood sample was also briefly examined.     

Capillary zone electrophoresis applied to the determination of the angiotensin-converting enzyme inhibitor cilazapril and its active metabolite in pharmaceuticals and urine

A capillary zone electrophoresis method has been developed for the quantitation of antihypertensive drug cilazapril and its active metabolite cilazaprilat in pharmaceuticals and urine. The separation of the compounds was performed in a fused-silica capillary filled with the running electrolyte, which consisted of a 60 mM borate buffer solution at pH 9.5. Under the optimized experimental conditions, the separation took less than 5 min. The analysis of urine samples required a previous solid-phase extraction step using C8 cartridges. The method was successfully applied to the determination of the drug and its metabolite in urine samples obtained from three hypertensive patients (detection limits of 115 ng ml(-1) for cilazaprilat and 125 ng ml(-1) for cilazapril) and to pharmaceutical dosage forms. The method was validated in terms of reproducibility, linearity and accuracy.     

Original paper application of cyclodextrins as modifiers in electrophoretic separation of metalloporphyrins

Several metallocomplexes of tetrakis-carboxyphenylporphyrin (TCPP) were separated on fused-silica capillary using CZE with UV-VIS detection. Metalloporphyrins of Co(II), Cu(II), Mn(II), Ni(II), and Zn(II) were formed directly in TCPP solution with addition of Cd(II) to increase the formation reaction rate. The composition of BGE, its concentration, and pH were optimized to ensure the stability of complexes and proper resolution. In particular, the problem of signals' shape was investigated and discussed. The presence of beta-CD in borate buffer significantly improved separation efficiency and signal shapes due to formation of inclusion complexes. Under the best separation conditions (50 mM borate running buffer at pH 9 with addition of 2 mM beta-CD, 30 kV applied voltage) a separation of metal complexes with TCPP was accomplished in 16 min.     

Capillary electrophoresis of anthraquinones from Cassia siamea

The separation and determination of two anthraquinones, emodin and chrysophanol, and two bianthraquinones, cassiamin A and cassiamin B, were achieved by capillary electrophoresis (CE). The running electrolyte used in this method was 0.05 M hydroxypropyl-gamma-cyclodextrin in 0.1 M borate buffer (pH 9) containing 10% acetonitrile, with an applied voltage of 20 kV. Application of this technique in the determination of the main bianthraquinones, cassiamin A and cassiamin B, of Cassia siamea is demonstrated in this paper.     

Determination of the angiotensin-converting enzyme inhibitor quinapril and its metabolite quinaprilat in pharmaceuticals and urine by capillary zone electrophoresis and solid-phase extraction

Quinapril is an antihypertensive drug commonly used in the treatment of hypertension and congestive heart failure. In this work, a capillary zone electrophoresis system is optimized for the analysis of quinapril and its active metabolite quinaprilat in urine, as well as for the determination of the drug and its combination with hydrochlorothiazide in pharmaceuticals. The separation takes place in a fused-silica capillary. The running electrolyte consists of a 60 mM borate buffer solution, pH 9.5. The analysis of urine samples requires a previous extraction step using C8 solid-phase cartridges. Under the optimum experimental conditions, the separation of the two analytes and the internal standard takes less than 5 min. The detection limits obtained (75 and 95 ng/mL for quinapril and quinaprilat, respectively) allow the application of the electrophoretic method to the determination of the drug and its metabolite in urine samples obtained from four patients treated with quinapril.     

Separation of the enantiomers of four chiral drugs by neutral cyclodextrin-mediated capillary zone electrophoresis

Summary Neutral cyclodextrin (CD)-modified capillary zone electrophoresis (CZE) has been applied to the chiral separation of four basic drugs— clorprenaline, benzhexol, esmolol and terazosin. Selector screening and concentration optimization experiments were performed. The resolution was 3.9 for clorprenaline, 2.3 for benzhexol, 3.1 for esmolol and 1.2 for terazosin when the running electrolyte was 60 mM hydroxypropyl-β-CD, 15 mM heptakis (2,3,6-Tri-O-methyl)-β-CD, 60 mM γ-CD and 60 mM heptakis (2,6-di-O-methyl)-β-CD, respectively, in 50 mM, pH 2.5 sodium phosphate buffer.     

Capillary electrophoretic determination of the constituents of Artemisiae Capillaris Herba

Two capillary electrophoretic methods, a micellar electrokinetic electrophoretic (MEKC) one and a capillary zone electrophoretic (CZE) one, were developed for the separation of 12 constituents in Artemisiae Capillaris Herba. Detection at 254 nm with 20 mM sodium dodecyl sulfate and 20 mM sodium borate buffer (pH 9.82) in MEKC or with 25 mM sodium borate and 6.75 mg/ml 2,3,6-tri-O-methyl-beta-cyclodextrin buffer in CZE was found to be the most suitable approach for this analysis. Within 42 min, the MEKC method could successfully separate 12 authentic constituents, whereof chlorogenic acid, however, appeared as a broad and split peak, and capillarisin and chlorogenic acid overlapped partially with other coexisting substances in crude extract of the herb. The CZE method could completely overcome these problems and was used to determine the amounts of capillarisin, chlorogenic acid, scopoletin and caffeic acid in the extract. The effect of buffers on the constituent separation and the validation of the two methods were discussed.