Ion-pairing liquid chromatographic method determination of ketoconazole and stress degradation in pharmaceutical formulations with fluorescence detection

Ion-pairing liquid chromatographic method was validated for determination of ketoconazole in shampoo and cream samples as per ICH guidelines. The chromatographic conditions were carried out in the isocratic mode using a mixture of methanol and 8 mM sodium dodecyl sulfate (pH 5.5) in a ratio of 45:55 v/v %, as mobile phase. The flow rate was set at 1.0 mL min-1. Chromolith RP-18e (100×4.6 mm) was used as the analytical column with a fluorescence detection at an excitation wavelength of 260 nm and an emission wavelength of 375 nm. The average percentage recovery of shampoo A, shampoo B, shampoo C, cream A and cream B were 99.88, 97.06, 99.58, 96.77 and 97.26, respectively. The limit of detection was 0.12 mg L-1. The drug decomposition under acid degradation, base degradation and oxidative degradation were found to be in the range of 91.63-94.70% indicating that the drug is resistant towards acidic conditions. The drug decomposition under thermal condition and photolysis condition were found to be in the range of 69.05-87.15% and 47.31-66.83% respectively, indicating that the drug decomposition is more sensitive under photolysis conditions. This method is suitable for the quality control of ketoconazole in commercial shampoo and creams.

本研究依据ICH指南要求，对用于测定洗发剂与乳膏样品中酮康唑（ketoconazole）含量的离子对液相色谱法（Ion-pairing liquid chromatography）完成了方法学验证。色谱条件采用等度洗脱模式，流动相为甲醇与8 mM十二烷基硫酸钠（pH 5.5）按45:55体积比配制的混合溶液，流速设定为1.0 mL·min⁻¹。分析柱选用Chromolith RP-18e（100×4.6 mm），采用荧光检测器进行检测，激发波长为260 nm，发射波长为375 nm。洗发剂A、洗发剂B、洗发剂C、乳膏A与乳膏B的平均加样回收率分别为99.88%、97.06%、99.58%、96.77%与97.26%，方法检测限为0.12 mg·L⁻¹。酮康唑在酸降解、碱降解及氧化降解体系中的残留率为91.63%~94.70%，表明该药物对酸性环境具备良好耐受性；而在高温降解与光解条件下，其分解率分别为69.05%~87.15%与47.31%~66.83%，提示该药物在光解环境下更易发生降解。该方法可满足市售洗发剂与乳膏中酮康唑的质量控制需求。