Abstract
A simple, stability-indicating liquid chromatographic method has been developed for the determination of methicillin sodium in the presence of its acid and alkaline-induced degradation products. A µBondapak-C
18
column was used with a mobile phase composed of acetonitrile/2% v/v acetic anhydride (55:45 v/v) at a flow rate of 1.8 mL/min. The detection was accomplished fluorometrically using an excitation wavelength of 280 nm and emission wavelength of 360 nm. The peak area versus concentration plot was linear over the range 1-10 µg/mL with a limit of detection of 0.1 µg/mL (2.38×10
−7
M). Between-day and within-day relative standard deviations were lower than 2%. The proposed method was successfully applied to the in-vitro determination of methicillin sodium in bulk material, dosage form, spiked urine, and spiked plasma, with minor modification of the mobile phase ratio in the case of spiked urine and plasma. The % recovery from human plasma (n=9) was 99.04±1.88 and from urine (n=8) was 99.3 6±1.77.