The alternating current polarographic behavior and determination of lansoprazole and omeprazole in dosage forms and biological fluids.

The alternating current (ACt) polarographic behavior of lansoprazole (LNS) and omeprazole (OMP) was studied in Britton Robinson buffers (BRb) over the pH range 4.1-11.5. In BRb of pH 9.6 and 10.5, well-defined ACt peaks were obtained for both LNS and OMP, respectively. The current-concentration plots were rectilinear over the ranges of 0.4-20 microg mL(-1) and 0.2-10 microg mL(-1) for LNS and OMP respectively. The minimum detection limits (S/N=2) were 0.02 microg mL(-1) (5.4x10(-8) M) and 0.01 microg mL(-1) (2.9x10(-8) M) for LNS and OMP, respectively. The proposed method was successfully applied to the analysis of the two drugs in their commercial capsules. The average percent recoveries were favorably compared to those obtained by reference methods. Co-administered drugs such as naproxen and methotrexate did not interfere with the proposed method. The proposed method was further extended to the in-vitro determination of the lansoprazole in spiked plasma, the percentage recoveries was 98.47+/-1.29 (n=4). The pathway for the electrode reaction for both drugs involved reduction of the sulphonyl group into the corresponding thiol group at the Dropping Mercury Electrode. The advantages of the method were time saving and more sensitive than the other published voltammetric method. Yet The present study is the first report on the use of alterating current polarography (ACt) in this respect.