Spectrophotometric determination of antipsychotic drug olanzapine in pharmaceuticals

Abstract EN

Two new sensitive spectrophotometric methods have been developed for the analysis of the antipsychotic drug, olanzapine (OLP) in pharmaceuticals.

The methods are based on the oxidation of OLP by a measured excess of cerium (IV) sulphate in H2SO4 medium.

This was followed by determination of the unreacted oxidant by reacting with either N-phenylanthranalic acid (NPA) and measuring the absorbance at 440 nm (Method A) or sulphanilic acid (SAA) and measuring absorbance at 545 nm (method B).

In both methods, the amount of cerium (IV) sulphate reacted corresponds to the amount of OLP.

The calibration graphs were linear over the ranges 0.3-1.8 and 5.0-75.0 μg ml-1 OLP for method A and method B, respectively.

The calculated molar absorptivity, Sandell sensitivity and limit of quantification for the methods are reported.

The intra-day precision (%RSD) and accuracy (%RE) ranged from 0.25 to 2.89 % and from 0.9 to 3.0 %, respectively, the inter-day RSD and RE values were within 3.5 % and 4.0 %, respectively.

The applicability of the methods was demonstrated by determining OLP in tablets with accuracy (%RE) of 3.15 to 3.60 and precision (%RSD) of 0.34-1.32.

The accuracy of the methods was further ascertained by recovery experiments via standard-addition procedure.