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.本研究依据国际人用药品注册技术协调会（ICH）指导原则，对用于洗发剂及乳膏样品中酮康唑（ketoconazole）含量测定的离子对液相色谱法（ion-pairing liquid chromatography）开展了方法学验证。色谱分析采用等度洗脱模式，流动相为甲醇与8 mmol/L十二烷基硫酸钠（pH 5.5）的混合溶液，体积比为45:55 v/v%，流速设定为1.0 mL/min。采用Chromolith RP-18e (100×4.6 mm) 作为分析色谱柱，以荧光检测器进行检测，激发波长为260 nm，发射波长为375 nm。A洗发剂、B洗发剂、C洗发剂、A乳膏及B乳膏的平均回收率分别为99.88%、97.06%、99.58%、96.77%及97.26%。本方法的检测限为0.12 mg/L。酮康唑在酸降解、碱降解及氧化降解条件下的药物留存率为91.63%~94.70%，表明该药物对酸性条件具有良好耐受性；而在热降解及光降解条件下的药物留存率分别为69.05%~87.15%及47.31%~66.83%，提示该药物在光解条件下更易发生分解。该方法可适用于市售洗发剂及乳膏中酮康唑的质量控制。