Abstract
Lansoprazole in human plasma using metronidazole as internal standard was determined quantitatively by a well developed and validated RP – HPLC method by UV detection. The extraction process involved a liquid – liquid extraction using a 70:30 % v/v mixture of t-butyl methyl ether and Dichloromethane. Both lansoprazole and the internal standard (metronidazole) were eluted under isocratic mode. A mixture of 50:50 % v/v methanol and 10mM mixed phosphate buffer (pH 3) at a flow rate of 1.2 mL/Minute was used as mobile phase. The wave length of detection is 285 nm. The method showed good linearity in the range of 50.25 – 2999.93 ng/mL. Matrix effects were not observed.
