High performance liquid chromatography assay method for simultaneous quantitation of formoterol and budesonide in Symbicort Turbuhaler

A sensitive and rapid high performance liquid chromatography method has been developed and used for the simultaneous determination of formoterol and budesonide in Symbicort Turbuhaler when assessing the aerodynamic characteristics of the emitted dose using Pharmacopoeial methods. This capability results in both time and cost saving.

The mobile phase composition was acetonitrile–5 mM sodium dihydrogen orthophosphate, pH 3 (60: 40% v/v), and was passed at 1.5 ml min−1 through a C18 column with a UV detection (wavelength 214 nm).

The method was shown to give good analytical performance in terms of linearity, precision (using phenylpropanolamine as an internal standard), sensitivity and solution stability. The intra-day precision for both formoterol and budesonide were 0.75% and 1.11%, respectively (n = 10). The limit of quantitation for formoterol was 10 μg L−1 and for budesonide was 120 μg L−1, and the limit of detection were 3 and 30 μg L−1, for both formoterol and budesonide, respectively.

The method has been applied to determine the content of the emitted dose and the fine particle dose of Symbicort Turbuhaler.