DETERMINATION OF PALBOCICLIB IN HUMAN PLASMA USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY – ULTRAVIOLET DETECTION

A simple, sensitive, and high-performance liquid chromatography ultraviolet detection (HPLC-UV) method was developed and validated for the quantification of palbociclib in human plasma. Plasma samples were processed by solid phase extraction using an Oasis hydrophilic-lipophilic balance extraction cartridge (1 mL, 30 mg). Commercial imatinib was used as an internal standard. Palbociclib and imatinib (IS) in human plasma were analyzed using a mobile phase of acetonitrile and 0.1% Triethylamine TEA (pH 3.3; adjusted with 50% Ortho-phosphoric acid) (70:30, v/v), on a Agilent Zorbax C18 column (150 × 4.6 mm i.d., 5 µm) using isocratic elution at a flow rate of 1.0 mL/min with ultraviolet detection at 266 nm. The method was validated over a concentration range of 0.1-3.0 µg/mL (r² ≥ 0.998) with coefficient of variation for intraday precision of 3.92%, 3.56% and 2.28% for 0.5, 1.5, and 2.5 µg/mL respectively. The lower limit of detection was 50 ng/mL. The extraction recovery rates for palbociclib ranged from 66.69% to 80.97%. The intra- and inter-day precision was below 5.0%, and the accuracy ranged from 89.40 – 112% over the linear range. No notable matrix effects were observed. The proposed RP-HPLC method was successfully applicable for clinical therapeutic drug monitoring programs and found suitable application in design pharmacokinetic studies.