高效液相色谱-荧光法测定对虾组织中红霉素的残留量

建立了高效液相色谱-荧光法测定对虾组织中红霉素残留量的检测方法。主要研究了样品前处理方法。提出了以乙腈为提取剂,正己烷去脂、二氯甲烷反萃的新的样品处理方式。该方法简单,灵敏度高,方法检出限为150μg／kg,回收率≥75％。     

Regioselectivity and crystal structure of erythromycin A oxime ketal derivatives

Three crystal structures of 2′, 4″-O-bis(trimethylsilyl) erythromycin A oxime ketal derivatives were determined and compared. Analogous protective groups on 9-oxime possessed various conformations, which resulted in very different steric congestion around 11-OH. The study on the conformations revealed the origin of the difference of regioselectivity as well as the reversal of selectivity from 11-OH to 6-OH.     

Novel erythromycin A derivatives: synthesis of 11,12-benzoxazine ketolides

A novel series of 11,12-benzoxazine ketolide derivatives of erythromycin A has been synthesized. The C11,C12-benzoxazine structure was constructed stereoselectively through an intramolecular Michael addition of a C12-O-(2-aminophenyl) group to the enone functionality of the 10,11-anhydro erythromycin A derivative 3.     

Voltammetry of the Erythromycin-Modified Glassy Carbon Electrode and Interaction With Dna

ABSTRACT

The chemically modified electrode (CME) which was constructed by covalently attaching Erythromycin (ERM) to a glassy carbon (GC) surface was investigated in Tris-HCl buffer (pH=6.0) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). In the potential range -0.5 to +0.4V, CME yields a pair of stable redox waves. It is the carbonyl group of the ERM molecule immobilized on the GC surface that behaves as a two-electron redox process involving one proton. The interaction of CME with DNA was also studied by DPV. The CME shows the same interaction with DNA as that in the solution. And the interactive model between ERM and DNA was proved by fluorescence in aqueous solutions.     

Development of a stability-indicating high performance liquid chromatography method for assay of erythromycin ethylsuccinate in powder for oral suspension dosage form

In this study an effective method was developed to assay erythromycin ethylsuccinate for an oral suspension dosage form. The chromatographic separation was achieved on an X-Terra™ C₁₈ analytical column. A mixture of acetonitrile–ammonium dihydrogen phosphate buffer (0.025 mol L^-1) (60:40, V/V) (pH 7.0) was used as the mobile phase, effluent flow rate monitored at 1.0 mL min⁻¹, and UV detection at 205 nm. In forced degradation studies, the effects of acid, base, oxidation, UV light and temperature were investigated showing no interference in the peak of drug. The proposed method was validated in terms of specificity, linearity, robustness, precision and accuracy. The method was linear at concentrations ranging from 400 to 600 μg mL⁻¹, precise (intra- and inter-day relative standard deviations <0.65), accurate (mean recovery; 99.5%). The impurities and degradation products of erythromycin ethylsuccinate were selectively determined with good resolution in both the raw material and the final suspension forms. The method could be useful for both routine analytical and quality control assays of erythromycin ethylsuccinate in commercial powder for an oral suspension dosage form and it could be a very powerful tool to investigate the chemical stability of erythromycin ethylsuccinate.     

无味红霉素的极谱研究及应用

无味红霉素是一种广谱临床抗生素,其分析方法已见报道的有薄层分离、生物自显影法和分光光度法。本文首次研究了无味红霉素的单扫极谱测定法,方法灵敏度可达0.05μg/mL,应用于血清和片剂分析,结果令人满意。并对极谱波性质作了初步探讨。 1 实验部分     

红霉素琥珀酸乙酯与茜素磺酸钠的荷移反应研究

研究了红霉素琥珀酸乙酯与茜素磺酸钠的荷移反应 ,建立了一种测定红霉素琥珀酸乙酯的方便、快捷的荷移分光光度法。红霉素琥珀酸乙酯与茜素磺酸钠在乙醇 -水介质中发生电荷转移反应 ,荷移络合物在波长 5 30 nm处有最大吸收 ,表观摩尔吸光系数为 7.90× 10 3 L· mol-1·cm-1,该络合物的组成为 1∶ 1,稳定常数是 1.3× 10 5。药物浓度在 10— 10 0 mg/L范围内服从比耳定律。当红霉素琥珀乙酯浓度为 5 0 mg/L时 ,6次测定结果的相对标准偏差为 1.33%。回收率 >98%。本法测定了红霉素琥珀酸乙酯片中有效成分的含量与药典法比较 ,二者结果吻合。     

红霉素肟及相关化合物的高效液相色谱分析

探讨和优化红霉素肟及相关化合物的HPLC分析色谱条件 ,紫外检测波长为 2 0 5nm ,使用Hitachi色谱系统 ,ODS C1 8色谱柱 (1 5 0mm× 4mmI.D .) ,控制流速 1mL min ,流动相为磷酸二氢钾 乙腈 (65∶3 5 ) ,明确指认了红霉素肟合成中主要成分的Z、E异构体 ,红霉素 6,9 半缩酮 ,红霉素 6,9 9,1 2螺缩酮的位置 ,同时对红霉素A ,红霉素C的吸收峰位置也进行了辨析 ,线性相关性良好。对红霉素肟及相关化合物的详细HPLC解析 ,为有效改进红霉素肟的合成工艺起到指导作用     

乳液聚合法制备红霉素分子印迹聚合物微球及其吸附性能

以大环内酯类抗生素红霉素(EM)为模板分子,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,十二烷基苯磺酸钠(SBS)为乳化剂,采用乳液聚合法制备了粒径均匀的分子印迹聚合物微球(EM-MIPMs). 通过核磁共振氢谱(¹H NMR)、紫外光谱和傅里叶变换红外(FTIR)光谱对模板分子和功能单体形成的复合物进行了研究,结果表明EM与MAA之间的相互作用力为氢键作用. 利用扫描电镜(SEM)、热重分析(TGA)仪对EM-MIPMs 的形貌和热稳定性进行表征,结果显示EM-MIPMs 为均匀规整的球型,平均粒径为4.24 μm,且有良好的热稳定性. 同时采用动力学,平衡吸附和选择性吸附实验对其吸附性能进行研究. 动力学研究结果表明,EM-MIPMs的吸附速率符合准二级动力学方程. 利用Langmuir 和Freundlich 吸附等温方程分别分析了EM-MIPMs 的平衡吸附数据,结果表明,EM-MIPMs 对红霉素有良好的结合性能,其吸附过程符合Langmuir 吸附模型,饱和吸附量为0.242 mmol·g^-1. EM-MIPMs的选择识别性能利用固相萃取法来考察,研究表明EM-MIPMs有着良好的特异识别选择性.