Novel HPLC Methods for the Assessment of Febuxostat and Allopurinol

Abstract

Three specific, sensitive and rapid RP-HPLC methods have been developed for the assessment of Febuxostat and Allopurinol in their pure and bulk pharmaceutical dosage forms based on UV or fluorescence detection. The first method describes the chromatographic separation and assessment of Febuxostat using an Agilent 1260 infinity series HPLC system equipped with an Agilent Eclipse plus C18 column (250 X 4.6 mm, 5µm particle size) at 45 o C and a UV detection at a wavelength of 318 nm. The mobile phase was 80 : 20 v/v% of acetonitrile : 5 mmol/L acetic/acetate buffer of pH 3.3 at a 0.75 ml/min flow rate, in the isocratic flow mode. The retention time was 5.1 ± 0.1 min. A 20 µl injection volume of three replicates was applied. A linear calibration graph was obtained for peak area versus Febuxostate concentration for 5.0 – 90.0 µg/ml Febuxostate with a regression equation of A = 127.81X + 12.337 and a correlation coefficient of 0.9998. The average recover was 99.09%. The limit of detection and lower limit of Quantitation were 1.6 and 4.9 µg/ml, respectively. The second method describes the chromatographic separation and assessment of Allopurinol using an Agilent 1260 infinity series HPLC system equipped with Prontosil cyano column C18 column (150 X 4.6 mm, 5µm particle size) at 25 o C and a UV detection at a wavelength of 250 nm. The mobile phase was 60 : 40 v/v% of methanol : 25 mmol/L KH2PO4 buffer of pH 4.60 at a 0.50 ml/min flow rate, in the isocratic flow mode. The retention time was 4.45 ± 0.10 min. A 20 µl injection volume of three replicates was applied. A linear calibration graph was obtained for peak area versus Allopurinol concentration for 10.0 – 90.0 µg/ml Allopurinol with a regression equation of A = 139.09X + 138.45 and a correlation coefficient of 0.9998. The average recover was 99.09%. The limit of detection and lower limit of Quantitation were 1.9 and 6.02 µg/ml, respectively.