Abstract

Oseltamivir phosphate (OP) is chemically ethyl (3R, 4R, 5S)-4-acetamino-5-amino-3-(ethylpropoxy)-1-carboxylate
phosphate used to treat flu virus (influenza).The drug is commercially available as tablets for oral administration. In the
present work two simple, economical, precise and accurate UV spectrophotometric methods have been developed for the
estimation of oseltamivir phosphate in bulk and pharmaceutical formulation .Method A is absorption maxima method in
which λmax was found to be 217.06nm. Method B is first order derivative spectroscopy where drug showed λmax at 214.35
nm. Amplitude (dA/dλ) was calculated and was plotted against concentration and regression equation was calculated.
Linearity was observed in the concentration range 5-25μg/ml (r =0.999) for the two methods. The % assay for the marketed
formulation for absorption maxima, first order derivative method was found to be 97.62%, 98.02% respectively. The
methods were validated with respect to linearity, precision and accuracy studies. Recovery studies for absorption maxima,
first order derivative was found to be 98.61%, 98.71%respectively. The methods were found to be simple, precise and
accurate and can be employed for routine quality control analysis of oseltamivir phosphate in bulk as well as from its dosage
form.

Key words: Oeltamivir phosphate, UVspectroscopy, Absorption maxima, First order derivative