Impurity profiling of a drug substances / Nur Salima Shamsudin

Carbimazole is an antithyroid drug and is used in treating hyperthyroidism. Carbimazole itself is inactive, but it is rapidly converted to methimazole. This thesis described a thin layer chromatography (TLC) method and a validated high performance liquid chromatography (HPLC) detection method to identify and also to determine the amount of impurity present in carbimazole sample. Solvents used in TLC method were dichloromethane, chloroform and acetone as mobile phase. The TLC plate used was TLC aluminium sheets, 20 x 20 cm, Silica Gel 60 F254. The HPLC was equipped with column ZORBAX 300SB-CI8, 5 pm, dimension 4.6 x 150 mm, manual injector with 20pl loop and a UV detector. The separation was achieved using acetonitrile and water as mobile phase at a flow rate of 1.2 ml/min.The impurity and amount of carbimazole in carbimazole tablet were found. The limit of detection on TLC method was 1 mg/ml while for HPLC was 0.025 pg/ml. A suitable method was developed to identify and quantitate carbimazole compound and its impurity in carbimazole tablet.