Estimation of Lansoprazole and Naproxen by Absorption Ratio Method in Tablet Dosage Form

An accurate, specific and precise new Absorption Ratio method was developed for the simultaneous determination of Lansoprazole and Naproxen. The method involved Q-absorption analysis based on the measurement of absorbance at two wavelengths, i. e λmax of Lansoprazole (284nm) and for Naproxen was (271nm) and Iso-absorptive point of both drugs (275nm). The linearity was found to be 10–35μg/ml (r2 =0.999) for NAP and 5–30μg/ml (r 2 =0.998) for LAN. Validation was performed as ICH guidelines for Linearity, accuracy, precision, LOD and LOQ. The limit of quantification of NAP was found to be 0.15μg/ml and for LAN was 1.7μg/ml. The limit of detection of NAP was found to be 0.04μg/ml and for LAN was 0.5μg/ml. The indicating proposed spectrophotometric method was accurate and precise for estimation of NAP and LAN in tablet dosage form.