A new Stability indicating RP-HPLC method for the determination of Apremilast-An Antirheumatic drug

Accuracy: The accuracy of the assay method was evaluated using standard addition method followed by recovery studies (80, 100 and 120%) Robustness: The robustness of the assay method was established by introducing very small changes in the optimized HPLC conditions that include detection wavelength, mobile phase composition and flow rate. Initially the stressed samples were analyzed using a mixture of 0.1% acetic acid: acetonitrile (50: 50, %v/v) with a flow rate of 1.0 ml/min in which the peak was obtained at Rt 9.7mins and also the resolution as well as peak symmetry were not satisfactory. [...]the mobile phase ratio was modified as 40:60, %v/v and the drug sample was analyzed where a sharp peak was eluted at 7.1 mins with tailing. [...]the mobile phase composition was adjusted to 20:80, %v/v and a sharp and symmetrical drug peak was eluted at 5.30 ± 0.02 mins (UV detection 203 nm). Robustness: Slight changes in flow rate, detection wavelength, mobile phase composition etc. affects the chromatographic response such as retention time, tailing factor and theoretical plates etc and the results were given in Table 3.