Leelavathi D E, Soffer E F, Dressler D E, Knowles J
J Pharm Sci. 1986 Apr;75(4):421-3. doi: 10.1002/jps.2600750423.
An automated high-performance liquid chromatographic method with electrochemical detection is described for the determination of indoramin, a new antihypertensive drug. The procedure involves a single extraction of the drug from alkaline plasma with chlorobutane. The chlorobutane extract is evaporated to dryness, reconstituted in methanol and injected into the chromatograph. Separation is achieved using a CN-bonded silica column and an isocratic elution with 0.01 M sodium phosphate in 50% acetonitrile. Detection is at 0.95 V applied potential on a glassy carbon electrode versus an Ag/AgCl electrode. Electrochemical methods that depend on a high oxidation potential suffer from rapid electrode passivation by significant amounts of impurities extracted from plasma. Therefore, the instrumentation includes a valve-switching unit to divert most of the impurities away from the electrode compartment; thus, maintaining sensitivity during the automated analysis of a large number of samples. An RSD of 5-15% was obtained in the concentration range of 0.5-100 ng/mL plasma. The limit of detection is 0.5 ng/mL. The method has been successfully used for the determination of indoramin in plasma samples from human subjects given a 50-mg oral dose of the drug.
本文描述了一种采用电化学检测的自动高效液相色谱法，用于测定新型抗高血压药物吲哚拉明。该方法包括用氯丁烷从碱性血浆中单次提取药物。氯丁烷提取物蒸发至干，用甲醇复溶后注入色谱仪。使用氰基键合硅胶柱，以含50%乙腈的0.01 M磷酸钠进行等度洗脱实现分离。在玻碳电极与Ag/AgCl电极之间施加0.95 V的应用电位进行检测。依赖高氧化电位的电化学方法会因从血浆中提取的大量杂质而导致电极快速钝化。因此，该仪器包括一个阀切换单元，以将大部分杂质从电极室转移开；从而在大量样品的自动分析过程中保持灵敏度。在血浆浓度范围为0.5 - 100 ng/mL时，相对标准偏差为5 - 15%。检测限为0.5 ng/mL。该方法已成功用于测定给予50 mg口服剂量该药物的人体受试者血浆样品中的吲哚拉明。
