High-performance liquid chromatographic determination of epimers, impurities, and content of the glucocorticoid budesonide and preparation of primary standard.

The new glucocorticoid budesonide, a 1:1 mixture of two epimers, was evaluated analytically with respect to drug content, impurities, and epimer distribution in the drug substance. Reversed-phase high-performance liquid chromatographic (HPLC) systems using octadecylsilane columns with different ethanol-water mixtures as eluents were used. Budesonide and its epimers were determined with recoveries of 100.3% (+/- 0.16 SD) and 99.7% (+/- 0.27 SD), respectively. Individual foreign steroids in the ranges of 0.05--0.2 and 0.2--2% were determined with mean recoveries of 93% (+/- 7.6 SD) and 97% (+/- 2.5 SD), respectively. Analysis of eight small-scale production batches of budesonide gave a recovery of 99.9% (+/- 0.39 SD) for the sum of budesonide and impurities. Analytical data and the procedure for preparation of a budesonide primary standard are given. The proposed HPLC procedure is faster, more accurate, more precise, and more selective than the usual pharmacopeial methods for corticosteroids.