Spectrophotometric Determination of Amiodarone and Ondansetron with Precipitation Reagents

Abstract

Amiodarone (AD) and ondansetron (SOT) form insoluble molecular complexes with iodine (I_2, method A), ammonium molybdate (AM, method B) or phosphomolybdic acid (PMA, method C) under acid conditions. In addition, colour reactions have been combined to estimate the precipitants (in turn AD or OST).
They are based on the colour formation with either unreacted
precipitant in the filtrate (I₂) or released precipitant from the
precipitate (AM or PMA) with chromogenic reagents such as p-N-methyl
amino phenol sulphate-sulphanilic acid (PMAP-SAc, λ_max
520 nm for I₂, method A), potassium thiocyanate (SCN^–, λ_max 465
nm for AM, method B) or cobalt nitrate-ethylene diamine tetraacetic
acid disodium salt complex (CoII-EDTA, λ_max840 nm for PMA,
method C). The methods obey Beer's law and the precision and
accuracy of the methods were checked by UV reference methods;
standard deviations were typically ≤ 0.584. Recoveries
were > 99.33%. Regression analysis of Beer's plots showed good
concentration ranges (2–12, 0.8–4.8), (4–24, 5–30) and (20–100,
8–48) μg mL^–1 for AD or OST in methods A, B and C respectively.
The applicability of the methods was examined by analysing tablets
of AD or OST.