Establishment and validation of a microfluidic capillary gel electrophoresis platform method for purity analysis of therapeutic monoclonal antibodies

Capillary and microfluidic chip electrophoresis technologies are heavily utilized for development, characterization, release, and stability testing of biopharmaceuticals. Within the biopharmaceutical industry, CE‐SDS and M‐CGE are commonly used for purity determination by separation and quantitation of size‐based variants. M‐CGE is used primarily as an R&D tool for product and process development, while cGMP release and stability testing applications are commonly reserved for CE‐SDS. This paper describes the establishment of an M‐CGE platform method to be used for R&D and cGMP applications, including release and stability testing, for monoclonal antibodies. The M‐CGE platform method enables testing for product development support and cGMP release and stability using the same method, and utilization of one CE technology for the entire lifecycle of a biopharmaceutical product. Critical method parameters were identified, and the analytical design space of those critical parameters was defined using design of experiments (DOE) studies. Once defined through DOE studies, the method design space was validated according to ICH Q2 (R1) guidelines. Additional molecules of the same validated class were verified for use in the method by experimental confirmation of accuracy, specificity, and stability indicating capabilities. The platform method model facilitates rapid utilization of the method in development and GMP testing environments, and eliminates the need for individual validations for assets of the same class entering early stage development.     

On-line concentration of proteins by SDS-CGE with LIF detection

We present a simple approach for on-line concentration of SDS-protein complexes by using poly(vinyl alcohol) (PVA) solution in CGE. In comparison to the coated capillary, the presence of EOF in CGE omitted the need to fill the capillaries with polymer solutions prior to the analysis. More importantly, we found that highly reproducible separation of eight proteins by 3.5% PVA was achieved between runs and without the regeneration of high bulk EOF; the RSD of migration times was less than 0.7%. To further improve the concentration sensitivity, neutral PVA was introduced into the capillary with the help of EOF to act as sieving matrix. The occurrence of stacking at the boundary between the PVA and the sample zone is mainly due to the retardation of proteins by PVA. As a result, the LODs at an S/N of 3 for SDS-protein complexes are of the order of sub-nM to several nM. For example, the LOD for BSA is 0.78 nM, which is a 91-fold sensitivity enhancement over the normal injection. In addition, our stacking method has been applied to the analyses of proteins in Escherichia coli cells. The peak for beta-galactosidase (E. coli) was observed after 0.1 microM beta-galactosidase was spiked into the E. coli samples.     

基于CGE模型的我国西北地区民族经济政策模拟和实证研究

民族经济政策的模拟评估方法的缺失一直以来是我国民族经济政策效果有效性验证的一个短板。本文构建了基于CGE的西北地区民族经济政策评估模型,针对一般转移性支付政策进行系统模拟、政策力度对西北地区的经济要素以及当地企业产出的影响程度纵向对比分析,以及与东部沿海地区横向对比分析。本文的政策评估建模和模拟分析可以为我国西部大开发战略中一般性转移支付政策提供相应的决策支持。     

国际油价波动对我国经济影响的CGE分析

石油价格变动会引起一个经济体全方位的反应.本文利用一个中国CGE模型—MCHUGE模型,研究油价上涨20%对我国经济发展的影响.研究结果表明,石油生产、加工、冶炼以及部分化工等跟原油关系最直接的产业将从石油涨价中获益;以石油为原料的行业由于成本不容易转嫁,大部分会受到石油涨价的影响;其他替代能源产业因需求大幅上升而涨价;汽车和机械制造业将受到一定的冲击.在此基础上,我们提出了一些政策建议.     

硫代反义寡核苷酸药物FT19有关物质的分析

为了进行硫代反义寡核苷酸药物FT19的质量控制研究,建立了用阴离子交换高效液相色谱(AX-HPLC)和毛细管凝胶电泳(CGE)分析自行合成的FT19有关物质的方法。设计合成了FT19的硫代不完全序列(P=O)1和短序列(n-x)并将它们作为已知杂质。在AX-HPLC上,使用的分析柱为DNA Pac PA-100 (4 mm×250 mm);流动相A为10 mmol/L NaOH-0.1 mol/L NaCl,流动相B为10 mmol/L NaOH-3 mol/L NaCl;梯度洗脱条件为流动相B液在8 min内从60%升至100%;流速1 mL/min;柱温40 ℃;检测波长为260 nm。CGE所用毛细管规格为内径100 μm,总长度为31 cm,有效长度为20 cm;电泳缓冲溶液为三羟甲基氨基甲烷（Tris）-硼酸-7 mol/L尿素,pH 8.5;采用电动进样,进样电压-10 kV;分离胶为250 g/L的聚丙烯酰胺;检测波长为254 nm。结果表明,FT19与硫代不完全的(P=O)1序列在AX-HPLC上能够达到基线分离,与短序列(n-1)在CGE上能达到基线分离。说明AX-HPLC和CGE联合应用能够很好地分析FT19中的有关物质。     

Combining ligation reaction and capillary gel electrophoresis to obtain reliable long DNA probes

New DNA amplification methods are continuously developed for sensitive detection and quantification of specific DNA target sequences for, e.g. clinical, environmental or food applications. These new applications often require the use of long DNA oligonucleotides as probes for target sequences hybridization. Depending on the molecular technique, the length of DNA probes ranges from 40 to 450 nucleotides, solid-phase chemical synthesis being the strategy generally used for their production. However, the fidelity of chemical synthesis of DNA decreases for larger DNA probes. Defects in the oligonucleotide sequence result in the loss of hybridization efficiency, affecting the sensitivity and selectivity of the amplification method. In this work, an enzymatic procedure has been developed as an alternative to solid-phase chemical synthesis for the production of long oligonucleotides. The enzymatic procedure for probe production was based on ligation of short DNA sequences. Long DNA probes were obtained from smaller oligonucleotides together with a short sequence that acts as bridge stabilizing the molecular complex for DNA ligation. The ligation reactions were monitored by capillary gel electrophoresis with laser-induced fluorescence detection (CGE-LIF) using a bare fused-silica capillary. The capillary gel electrophoresis-LIF method demonstrated to be very useful and informative for the characterization of the ligation reaction, providing important information about the nature of some impurities, as well as for the fine optimization of the ligation conditions (i.e. ligation cycles, oligonucleotide and enzyme concentration). As a result, the yield and quality of the ligation product were highly improved. The in-lab prepared DNA probes were used in a novel multiplex ligation-dependent genome amplification (MLGA) method for the detection of genetically modified maize in samples. The great possibilities of the whole approach were demonstrated by the specific and sensitive detection of transgenic maize at percentages lower than 1%.     

碳关税影响我国经济发展的动态一般均衡研究

碳关税是面向未来经济发展模式的新型贸易政策,兼具环境规制和贸易政策的双重功能.论文采用2002-2030年的中国动态CGE模型,构造“虚拟”碳关税方程,设计了基于总能耗的分行业碳排放密度的模拟方案,讨论是否存在“波特假说”情形下对中国工业制成品征收30美元/吨的碳关税的动态影响.研究结果表明:碳关税对不同类型出口品具有不同程度的动态影响,但总出口下降幅度要弱于进口、投资以及消费下降幅度.“波特假说”在一定程度上改善了不利的经济影响,但长期而言单位GDP碳排放的减少并不显著.     

毛细管电泳技术在单克隆抗体药物分析中的应用

单克隆抗体药物在生物制药行业占有重要地位,是生物医药领域发展的主要方向。因此,单克隆抗体药物的质量控制已成为全球生物制药企业及法规机构关注的热点,对单克隆抗体药物精确表征的需求日益增加。毛细管电泳技术具有分离效率高、分析速度快、分离模式多、样品用量少等特点,已成为单克隆抗体药物分析和质量控制的重要手段。该文对毛细管凝胶电泳、毛细管等电聚焦、毛细管区带电泳等模式在单克隆抗体药物的纯度分析、等电点测定、电荷异质性分析和N-寡糖分析的应用进行综述,以期为国内单克隆抗体研究开发和生产的企事业单位提供技术参考。