Ortho phosphoric acid (OPA).

A simple and reproducible method was developed for carbimazole by Reverse Phase High Performance Liquid Chromatography (RP-HPLC). Carbimazole was separated on C18 column [4.6x250mm, particle size 5μm] at the UV detection of 291nm. Methanol and OPA (0.1%) was used as a mobile phase with various ratios and flow rates, eventually 80:20 v/v Methanol and OPA (0.1%) was being set with the flow rate of 0.7mL/min. The statistical validation parameters such as linearity, accuracy, precision, inter-day and intra-day variation were checked, further the limit of detection and limit of quantification of carbimazole concentrations were found to be within the limits. Recovery and assay studies of carbimazole were within 99 to 102% indicating that the proposed method can be adoptable for quality control analysis of carbimazole.