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OBJECTIVE@#To establish a micellar electrokinetic capillary chromatography-based method for identification and quantitative detection of interleukin-12 (IL-12) and analysis of its unfolding process.@*METHODS@#An uncoated fused-silica capillary (inner diameter 50 μm) with a total length of 48.5 cm (40 cm to the detector) was used for the experiment. The factors influencing the separation efficiency of IL-12 were analyzed, and a standard curve of IL-12 concentration was established. The mixture of IL-12 and anti-IL-12 antibody was incubated in a water bath at 38 ℃ for 40 min, and capillary electrophoresis was then performed under the same conditions. The results were compared with those of IL-12 and anti-IL-12 antibody to identify IL-12. IL-12 and dithiothreitol (DTT) were incubated at 60 ℃ in water bath for different lengths of times, and the unfolding process of IL-12 was analyzed based on electrophoresis results of IL-12 in different states.@*RESULTS@#A micellar capillary electrophoresis on-line sweep method was established with 80 mmol/L borate (pH=9.3) containing 30 mmol/L sodium dodecyl sulfate (SDS) as the buffer solution. This system showed a good linear relationship between the peak area and the mass concentration of IL-12 with a linear correlation coefficient of 0.9991 within the linear range of 2 to 120 ng/L. As the incubation time of IL-12 and DTT prolonged, the disulfide bond of IL-12 gradually opened and resulted in distinct changes in the protein peak.@*CONCLUSIONS@#This capillary electrophoresis-based method is simple and sensitive for IL-2 analysis and allows rapid detection of changes in IL-12 content in the setting of tumors and analysis of the possible causes.
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OBJECTIVE: To establish a method for analysis of related substances in biapenem with micellar electrokinetic capillary chromatography(MEKC). METHODS: In order to improve the separation selectivity, a zwitterionic surfactant, 3-(N, N-dimethylhexadecylammonium)-propanesulfonate(PAPS) was used. The optimal separation conditions were as follows: the total length of the capillary was 48.5 cm (the effective length was 48 cm), the buffer was 90 mmol•L-1 tris(hydroxymethyl)aminomethane (tris)-phosphate buffer containing 17 mmol•L-1 PAPS and 3 mg•mL-1 polyoxyethylene 23 lauryl ether (Brij 35), the applied voltage was 22 kV, and the capillary temperature was controlled at 30℃. Further more, the specificity, linearity, precision, repeatability, stability and durability were studied. The contents of related substances in biapenem commercial samples were analyzed. RESULTS: The MEKC method, which was a comparable analysis method to HPLC, successfully separated the adjacent impurities of biapenem by using the zwitterionic surfactant PAPS. The specific test showed that this method was especially suitable for the detection of biapenem dimers A, B and open-ring compound. CONCLUSION: In this method, MEKC with zwitterionic surfactant is for the first time applied to the analysis of related substances in biapenem (amphoteric drugs). It provides a feasible analysis method with high sensitivity, good specificity and reproducibility for the quality control of biapenem.
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Objective To establish a micellar electrokinetic capillary chromatography method for content determination of geniposide in Biyuanshu Oral Liquid. Methods Acetaminophen was used as an internal standard, and the separation was performed on an uncoated fused silica capillary of 52 cm × 50 μm ID (42 cm effective length) with the separation voltage of 25.0 kV. The running buffer contained 50 mmol/L borax, 100 mmol/L sodium dodecyl sulfate and 15％ acetonitrile (pH=10). The sample was injected by pressure (10 s, 0.5 psi) and detected at 238 nm. Results Geniposide was in good linearity range of 15.02–320.48 μg/mL (r=0.9995). The repeatability (low, medium and high concentration of samples) and intermediate precision assays gave satisfactory RSD values of less than 1.77％and 2.01％, respectively. The average recovery of geniposide in Biyuanshu Oral Liquid was 97.50％ and the RSD was 4.43％. The contents of geniposide determined by micellar electrokinetic capillary chromatography were in accordance with the results of HPLC analysis. Conclusion The method is simple, fast, accurate and precise, which can be used for the content determination of geniposide in Biyuanshu Oral Liquid.
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Abstract A rapid and sensitive micellar electrokinetic capillary chromatography method with UV photodiode-array detection was developed for the simultaneous determination of atorvastatin and ezetimibe in fixed dose drug combination. Experimental conditions such as buffer concentration and pH, surfactant concentration, system temperature, applied voltage, injection parameters were optimized in order to improve the efficiency of the separation. The best results were obtained when using fused silica capillary (48 cm length X 50 µm ID) and 25 mM borate buffer electrolyte at pH 9.3 containing 25 mM SDS, + 30 kV applied voltage, 20 ºC system temperature. The separation was achieved in approximately 2 minutes, with a resolution of 7.02, the order of migration being atorvastatin followed by ezetimibe. The analytical performance of the method was verified with regard to linearity, precision, robustness and the limit of detection and quantification were calculated.
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Cromatografia Capilar Eletrocinética Micelar/métodos , Ezetimiba/administração & dosagem , Atorvastatina/administração & dosagem , Preparações Farmacêuticas/análise , Fracionamento da Dose de RadiaçãoRESUMO
OBJECTIVE:To develop a simple micellar electrokinetic capillary chromatography for determination of theophylline concentration in human plasma. METHODS: The determination of plasma sample(without any pretreatment) was performed on un-coated fused-silica capillaries (at an effective length of 21 cm) in which the cathodic buffer solution (solution A) was 15 mmol?L-1 borax(pH=10) and the running buffer solution(solution B) was sodium dodecyl sufate (SDS)(200 mmol?L-1) -contained solution A. The sample was injected into capillary by pressure with separation voltage of 12 kV;the UV detection wavelength was set at 280 nm;quantitation was performed by external standard peak area method. RESULTS: The average determination time of each sample was 11 min;the linear range of theophylline was 1.25～40 ?g?mL-1 with its lowest detectable limit at 0.5 ?g?mL-1;the average methodological recovery was 90.33%(RSD=2.51%);the intra-day RSD was 2.34%～3.36% and the inter-day RSD was 2.03%～6.51%,respectively. CONCLUSION: The developed method is simple,rapid and sensitive and it is applicable for the therapeutic drug monitoring of theophylline.
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OBJECTIVE: A micellar electrokinetic capillary chromatography(MECC) method was established for determination of benzoic acid and salicylic acid in Zuguang san.METHODS: An uncoated silica capillary(75 ?m?55 cm,effective length 47 cm) was used with 20 mmol?L-1 borate-30 mmol?L-1 SDS-4% methanol(pH 9.8) as the running buffer solution.The internal standard was antiscorbic acid.The detection wavelength was set at 250 nm.RESULTS:The calibration curves were linear in the range of 120～320 ?g?mL-1 for benzoic acid(r=0.999 8) and 80～320 ?g?mL-1(r=0.999 5) for salicylic acid.The average recoveries were 98.37% and 100.69%,respectively and the RSD were 4.47%(n=9) and 1.61%(n=9),respectively.CONCLUSION: MECC method was proved to be simple,sensitive and reproducible with high recovery rate and it is applicable for the determination of the contents of benzoic acid and salicylic acid in Zuguang san.
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This article reviewed the feature and the advances in the application of micellar electrokinetic capillary chromatography(MECC),an important mean of high performance capillary electrophoresis(HPCE),for the analysis of complicated component of medicine,.The analysis of multi-component of routine medicine,chiral drugs,illicit drugs,Chinese medicine,drug and its metabolites were introduced.
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Object To isolate and identify the four active constituents, chrysophanol, emodin, rhaponticin and rhein in rhubarb Methods Micellar electrokinetic capillary chromatography (MECC) with a buffer solution of 5 mmol/L H 3BO 3 NaOH containing 20 mmol/L of sodium deoxycholate (SDC) (pH=10) was used for their separation at a voltage of 17 kv Results The four active constituents were completely separated within 5 min Conclusion This method was found to be simple and rapid and gave satisfactory results
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Objective To develop a method for simultaneous determination of benzodiazepines in human whole blood by SPE-Micellar electrokinetic capillary chromatography.Methods With the Clenbuterol as internal standard,Oasis column was used to extract the drugs from whole blood.The separation was performed on a fused-silica capillary of 75?m ID?50.2cm(40cm of effect length).The running buffers were sequentially used as 15mmol/L phosphates→15mmol/L sodium borate(pH8.2)→30 mmol/L SDS,and 18% methanol served as an organic modifier.Sample solution was injected with pressure mode,and the running voltage was 25kV.The detection wavelength was set at 230nm.Results The linear ranges of the calibration curves were from 0.02 to 1.6?g/ml,and the limits of detection ranged between 5 ng/ml and 50 ng/ml.The within-day and between-day precision was less than 12%.Conclusion The method developed for determination of benzodiazepines in human whole blood is effective,simple and reliable,with which 9 benzodiazepines may be simultaneously separated.