Alkaline degradation of clavulanic acid and high performance liquid chromatographic determination by post-column alkaline degradation.
作者:JUN HAGINAKA、HIROYUKI YASUDA、TOYOZO UNO、TERUMICHI NAKAGAWA
DOI:10.1248/cpb.31.4436
日期:——
Alkaline degradation of clavulanic acid in methanol and in aqueous solution has been investigated. Potassium clavulanate was degraded in methanol and in NaOH-saturated methanol to yield methyl 8-hydroxy-6-oxo-4-aza-2-octenoate (I). which showed ultraviolet (UV) absorption with λmax 268nm (methanol). The UV absorption of I almost disappeared in acidic conditions, and reappeared on subsequent realkalization, suggesting interconversion between I and its protonated form. It was suggested that potassium clavulanate might be rapidly hydrolyzed in alkaline aqueous solutions to 8-hydroxy-6-oxo-4-aza-2-octenoic acid (II), which has strong UV absorption around 260 nm. The acid-base interconversion was also observed between II and its protonated form, the latter exhibiting almost no UV absorption around 260 nm. An ion-pair reversed-phase high performance liquid chromatography method with the alkaline degradation reaction incorporated into post-column has been developed for the determination of clavulanic acid in plasma and urine. After separation from regular components of plasma and urine, clavulanic acid is degraded in NaOH solution in a reaction coil followed by detection of the UV absorbance of the degradation product at 270 nm. The procedure was quantitative over a wide range of clavulanic acid concentrations in plasma and urine down to 0.1 μg/ml.
研究了克拉维酸在甲醇和水溶液中的碱性降解。克拉维酸钾在甲醇和 NaOH 饱和的甲醇中降解,生成 8-羟基-6-氧代-4-氮杂-2-辛烯酸甲酯(I),其紫外线(UV)吸收率为 λmax 268nm(甲醇)。在酸性条件下,I 的紫外线吸收几乎消失,但在随后的再碱化过程中又重新出现,这表明 I 与其质子化形式之间存在相互转化。有研究表明,克拉维酸钾可能会在碱性水溶液中迅速水解成 8-羟基-6-氧代-4-氮杂-2-辛烯酸(II),后者在 260 纳米附近有强烈的紫外线吸收。还观察到 II 与其质子化形式之间的酸碱相互转化,后者在 260 纳米附近几乎没有紫外线吸收。本研究开发了一种离子对反相高效液相色谱法,并在柱后加入了碱性降解反应,用于测定血浆和尿液中的克拉维酸。将克拉维酸与血浆和尿液中的常规成分分离后,在反应线圈中的 NaOH 溶液中进行降解,然后在 270 纳米波长处检测降解产物的紫外吸光度。该程序可在血浆和尿液中低至 0.1 μg/ml 的克拉维酸浓度范围内进行定量检测。