The effect of column age on system suitability parameters for an HPLC assay of bitolterol mesylate aerosols

A reversed-phase ion-pairing HPLC method is developed for bitolterol mesylate (Tornalate, Winthrop-Breon) in aerosol dosage forms. Using data acquired by this method during a two-year period, the effect of ODS-3 column age on system suitability parameters is assessed. A BASIC program is used to calculate the resolution factor between bitolterol and colterol triester, capacity factors, number of theoretical plates, and tailing factors in studies that followed the performance of one column during this time period and five columns of different ages under normal usage. A 15 to 30% reduction in column performance per year is found.