顶空毛细管气相色谱法测定盐酸克伦特罗中溶剂残留

摘 要 目的:建立盐酸克伦特罗中乙醇、异丙醇、二氯甲烷3种有机溶剂残留量的分析测定方法。方法: 顶空毛细管气相色谱法,FID检测器,进样口温度为140℃,检测器温度为250℃,DB-624石英毛细管柱（30 m×0.32 mm,1.8 μm）,起始柱温为40℃,维持7 min,再以30℃·min^-1升至200℃,维持5 min。顶空瓶平衡温度为80℃,平衡时间为45 min。结果:被测物均能得到很好的分离,峰面积与浓度呈良好的线性关系,精密度和回收率良好。结论:本方法灵敏、准确、可靠,可用于盐酸克伦特罗溶剂残留的质量控制。     

顶空气相色谱法测定硝唑尼特中的残留溶剂

目的:建立项空气相色谱测定药物硝唑尼特中残留溶剂的方法.方法:采用DM-WAX毛细管色谱柱(30 m×0.25 mm,0.5 μm);柱温采取程序升温;进样口温度为200℃;FID检测器,检测器温度为250℃;顶空进样,平衡温度为80℃,平衡时间为30 min;以N,N-二甲基甲酰胺为溶剂测定硝唑尼特原料药中丙酮、二氯甲烷的残留量.结果:在本文的色谱条件下,各有机溶剂均能得到有效分离,丙酮、二氯甲烷的浓度分别在250～750 μg·ml-1(r=0.9991)、30～90 μg· ml-1(r=0.9991)范围内线性关系良好;平均回收率分别为99.15％、99.18％,RSD分别为2.17％、2.97％(n=9).结论:本方法简便、快速、准确,可有效检测硝唑尼特中的残留溶剂.     

顶空毛细管气相色谱法测定盐酸莫西沙星中残留溶剂的含量

目的：建立盐酸莫西沙星中醋酸、乙酸乙酯、甲醇、乙醇、乙腈5种残留溶剂含量的测定方法。方法：顶空毛细管气相色谱法,氢火焰离子化检测器,醋酸以二甲基亚砜为溶剂,色谱柱为DB-FFAP（0．25mm×30m,0．25μm）;乙酸乙酯、甲醇、乙醇、乙腈以水为溶剂,异丙醇为内标,色谱柱为HP-INNOWax（0．32mm×30m,0．5μm）。结果：5种残留溶剂在对应于限度的20％～200％浓度范围内有良好的线性关系,平均回收率为97．3％～108．4％。结论：所建方法简单,准确,重现性好,可用于盐酸莫西沙星残留溶剂的含量控制。     

顶空毛细管气相色谱法测定单唾液神经节苷脂中有机溶剂残留量

目的 　建立气相色谱法测定单唾液神经节苷脂中有机溶剂甲醇、丙酮、氯仿残留量的方法。方法 　采用顶空毛细管气相色谱法 ,采用 DB-62 4大口径毛细管柱 (3 0 m× 0 .5 3 mm× 3 μm) ;氢火焰离子化检测器 (FID) ,以水为溶剂 ,初始柱温为 40℃维持 3 min,以 10℃ /min的速率升温至160℃ ,维持 3 min,进样口温度 ;14 0℃ ;检测器温度 :2 5 0℃ ;以高纯氮气为载气 ,流速 3 .0 ml·min- 1 ;分流比∶ 1∶ 5 ,实现了各组分的基线分离。结果 　本法具有良好的线性 ,r在 0 .9995～ 0 .9999之间 ,RSD小于 5 % (n=5 )。结论 　经方法学验证 ,该方法灵敏度、准确度均达到有机溶剂残留量的检测要求 ,可用于原料药单唾液神经节苷脂中残留溶剂的检测。     

Heteroarm Star Polystyrene‐block‐Poly(4‐vinylpyridine): Multiple Morphologies in Dilute Solutions

Synthesis and solution morphologies of four new heteroarm star polystyrene‐block‐poly(4‐vinylpyridine) were studied. As the water content increased, a morphological transformation of heteroarm PS₄‐P4VP₄ from spheres to cylinders, vesicles, and large compound vesicles was observed. The morphology of PS₄‐P4VP₄ in the solvent mixture of DMF/water or 1,4‐dioxane/water was spherical, but changed to large compound micelles in THF/water. As the P4VP molar ratio decreased, the morphology changed from spherical mixed with cylindrical to vesicles, giant vesicles, and then to LCMs. The present study demonstrated the formation of multiple morphologies through manipulating solvent polarity and block ratio in dilute solution.

     

顶空进样法测定更昔洛韦的残留溶剂

目的：建立测定更昔洛韦原料中有机溶剂残留量的方法。方法：采用顶空进样毛细管气相色谱法,HP-5毛细管柱;以氮气为载气,流速为1ml／min,FID检测器,以二甲基亚砜为溶媒,采用程序升温法测定更昔洛韦原料药中乙醇、乙酸乙酯和N,N-二甲基甲酰胺（DMF）的溶剂残留量。结果：更昔洛韦原料药中乙醇、乙酸乙酯和N,N-二甲基甲酰胺（DMF）3种有机溶剂完全分开,浓度在考察范围内与峰面积具有良好的线性关系,r为0．9992-0．9995,精密度RSD分别为1．45％、2．01％和1．04％,平均回收率分别为99．7％、102．1％和97．3％,检测限分别为30ng／ml、45n咖l和82ng／ml。结论：本法快速、灵敏、准确,可用于更昔韦洛原料中有机溶剂残留量的测定。     

Superhydrophobic Porous PLLA Sponges with Hierarchical Micro‐/Nano‐Structures for High‐Efficiency Self‐Cleaning

Porous poly (l ‐lactic acid) (PLLA) sponges have received rapid development in the materials science and energy fields due to their good biocompatibility and degradability. Herein, hierarchical micro‐/nano‐structures of PLLA sponges are successfully prepared by the microphase separation method to investigate the influence of non‐solvents on PLLA microtopography. The interaction ability between PLLA and various alcohol non‐solvents is precisely calculated by using the Flory–Huggins equation. SEM results show that the porosity of PLLA surfaces increases with increasing non‐solvent solubility parameters at a certain range. When the solubility parameters of alcohol non‐solvents are much higher than that of PLLA, PLLA bulks accumulate on the surfaces, mainly caused by its insolubility. DSC curves disclose that the crystallinity has a positive relationship with contents and solubility parameters of alcohol non‐solvents. Furthermore, these porous PLLA surfaces show strong water repellency and self‐cleaning ability so that the contaminant can be quickly cleared away from the PLLA surfaces. This study provides a new insight into understanding the formation process of PLLA porous materials and the wetting variation for high‐efficiency self‐cleaning.     

Cloning and expression of rat CYP2E1 in Saccharomyces cerevisiae: detection of genotoxicity of N-alkylformamides

A cDNA coding for rat cytochrome P450 2E1 was cloned into the multicopy vector pYeDP60 and expressed in haploid RSY6 and diploid RS112 yeast strains of Saccharomyces cerevisiae under control of the GAL10-CYC1 promoter. Spectral and catalytic properties of the expressed 2E1 were examined in whole cells or microsomes of both strains. The level of CYP2E1 obtained in RS112 (200 pmol/mg microsomal protein) was the highest among CYP2E1 produced in the various expression systems. The monooxygenase activity in the microsomes of both strains, measured as aniline hydroxylase, was found comparable to that of control rat hepatic microsomes. In a reconstituted system in the presence of exogenous rat P450 reductase, their activity increased about 10-fold. When exposed to the carcinogen NDMA, a known 2E1 substrate, the recombination frequency determined in the 2E1-expressing RS112 cells was enhanced, in a dose-dependent manner, up to 20-fold. The exposure of the same cells to the hepatotoxic solvents, N-methyl- and N-ethylformamide, resulted in an induction of recombination frequency, which was not observed in the void plasmid containing RS112 cells in the presence of S9 hepatic fractions from pyrazole-induced rats, as a specific exogenous metabolic activation system. These results demonstrate that the 2E1-expressing cells metabolize the two N-alkylformamides to genotoxic intermediates and, therefore, they provide an useful tool to study the bioactivation mechanism of potential P450 2E1 substrates.     

Green chemistry for chemical synthesis

Green chemistry for chemical synthesis addresses our future challenges in working with chemical processes and products by inventing novel reactions that can maximize the desired products and minimize by-products, designing new synthetic schemes and apparati that can simplify operations in chemical productions, and seeking greener solvents that are inherently environmentally and ecologically benign.     

Evaluation of the European Pharmacopoeia method for control of residual solvents in some antibiotics

Residual solvents (RS) are volatile organic chemicals that are used or produced during the manufacturing process of drug substances or excipients. The European Pharmacopoeia (Ph. Eur.) limits the amount of RS in pharmaceuticals, considering the International Conference on Harmonization (ICH) of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines for RS. According to the Ph. Eur. general method, water insoluble samples may be analyzed using DMF as dilution solvent at high equilibration temperatures such as 105 degrees C. This could be problematic in the case of antibiotics, many of which are water insoluble and temperature sensitive. Moreover, antibiotics are complex in nature and beside RS, one can expect several other volatile impurity peaks in the chromatogram. In this study, the Ph. Eur. method for RS analysis was evaluated for selected groups of antibiotics. An alternative dilution medium was proposed (DMSO-water), which offers optimum sensitivity while working at lower equilibration temperatures such as 80 degrees C. The optimized method was investigated for precision, accuracy, linearity and detection limits.