Development and validation of a new bioanalytical method for quantification of CDK4/6 inhibitor in Spiked Human Plasma by HPLC-UV

A sensitive and accurate high performance liquid chromatography method utilizing ultraviolet/visible light detection (HPLC-UV) for the quantification of Ribociclib in Spiked Human Plasma by HPLC-UV was developed and validated. Ribociclib (RCB) and the internal standard (IS), Trifluridine, were first extracted from plasma samples by a simple Protein Precipitation extraction using Acetonitrile. Plasma concentration of RCB and internal standard were then analyzed by applying reversed phase chromatography using Orochem orosil C18 (4.6 mm × 250 mm, 5 μ) and elution with a isocratic mobile phase consisting of 10 mM phosphate buffer – Acetonitrile (60:40, v/v) adjusted to pH 3.0 at a flow rate of 1.0 ml/min. Detection of RCB and the IS was subsequently done at a wavelength of 260 nm. The limit of quantification was 10 ng/ml. The calibration curve was linear (R2>0.998) over the concentration range of 10-1000 ng/ml. For human plasma, the accuracy and precision were within ±15% and ≤15%, respectively, for all concentrations, except for the lower limit of quantification, where they were within ≤20%.