Selective semi-micro and micro determination of olanzapine in pharmaceuticals using periodate

One titrimetric and two spectrophotometric methods which are simple, selective, sensitive and cost-effective are described for the determination of olanzapine (OLP) in bulk drug and in tablets Using sodium periodate as the oxidimetric reagent in buffer medium. In titrimetry, OLP was oxidized by a measured excess of periodate in borax-boric acid buffer medium followed by the iodometric determination of the unreacted oxidant in the same conditions and the method is applicable over 8-14 mg range and the calculations are based on a 1 : 1 stoichiometry (OLP: NaIO4). Spectrophotometry involves addition of a known excess of periodate to OLP in buffer medium the residual periodate is then reacted with excess of iodide and the liberated iodine (I-3(-)) is either measured at 350 nm (method A) or reacted with starch followed by the measurement of starch-iodine chromogen at 560 nm (method B). The spectrophotometric methods are applicable over the ranges 0.5-5.0 mu g ml(-1) (method A) and 0.5-4.0 mu g ml(-1) (method B). The methods were applied successfully to the determination of OLP in tablets.