Department of Pharmaceutical Chemistry, Friedrich Schiller University Jena, Jena, Germany.
Electrophoresis. 2009 Nov;30(22):3891-6. doi: 10.1002/elps.200900060.
A CE assay for the simultaneous determination of the impurities of levodopa listed in the European Pharmacopoeia including the (R)-enantiomer was developed and validated. The analysis was performed in a fused-silica capillary employing sulfated beta-cyclodextrin as chiral selector at an applied voltage of 20 kV and a temperature of 18 degrees C. The optimized background electrolyte consisted of 0.1 M sodium phosphate buffer, pH 2.0, containing 6 mg/mL sulfated beta-cyclodextrin. L-phenylalanine was used as the internal standard. The assay was validated in the range of 0.1-1.0% for the impurities at a concentration of levodopa of 2 mg/mL. The effect of different batches of sulfated beta-cyclodextrin was investigated using levodopa and L-tyrosine as critical pair. The method was applied to determine the purity of several samples of levodopa including the chemical reference substance of the European Pharmacopoeia.
建立并验证了一种用于测定《欧洲药典》中列出的左旋多巴杂质（包括其（R）对映体）的 CE 分析方法。在熔融石英毛细管中进行分析，在 20kV 的外加电压和 18°C 的温度下，采用硫酸化β-环糊精作为手性选择剂。优化后的背景电解质由 0.1M 磷酸钠缓冲液（pH2.0）组成，其中含有 6mg/mL 的硫酸化β-环糊精。L-苯丙氨酸被用作内标。在左旋多巴浓度为 2mg/mL 的情况下，该方法在 0.1-1.0%的杂质浓度范围内进行了验证。使用左旋多巴和 L-酪氨酸作为关键对，考察了不同批次硫酸化β-环糊精的影响。该方法应用于测定几种左旋多巴样品的纯度，包括欧洲药典的化学参比物质。
