Spectrophotometric and FIA methods for determination of Loratadine in pharmaceutical formulations based on charge transfer reaction

A rapid and sensitive Spectrophotometric and FIA method are described for the determination of Loratadine drug in both pure and dosage forms. The determination was based on the formation of charge transfer complexes between metol (N-methyl-p-hydroxy aniline) as π -acceptor and the studied drugs as n-donors in acetonitrile a polar aprotic solvent.

The colored product is measured at λmax 540 nm. Under the optimum conditions calibration graph was observed a linear from 10–50 μg ml⁻¹ LOR and with correlation coefficient not less than 0.9991 which was suitable for the quantitative determination of the drug. The molar absorbitivity was 2.431 × 104L.mole⁻¹.cm⁻¹, and sandell sensitivity of 0.01162μg cm⁻². The relative standard deviation of the proposed method was 0.5–2.4% depending on the concentration of LOR. The proposed method was successfully applied to the determination of LOR in tablets and syrups.