Simultaneous Determination of 14 Illegal Adulterants in Chinese Proprietary Medicines Using Reversed-Phase Ion-Pair LC

A reversed-phase ion-pair liquid chromatography (RP-IPC) method coupled with DAD was developed for simultaneous determination of 14 synthetic anti-diabetic drugs in Chinese proprietary medicines (CPMs). The separation was performed on a C18 column with a mobile phase consisting of acetonitrile and aqueous solution containing 1.0 mmol sodium dodecyl sulphate (SDS) and 0.10% triethylamine (adjusted to pH 3.75 using phosphoric acid), at a flow rate of 0.8 mL min−1 with gradient elution. Assay validation of the proposed RP-IPC method was fully carried out. Accuracy and precision of the method met the acceptable criteria, and linearity was good. In contrast to existing methods, this validated method is more comprehensive and effective for determination of anti-diabetic adulterants in CPMs in routine laboratories, and was successfully applied to the analysis of 26 samples from the local market.