LC method for telithromycin in tablets: a stability-indicating assay

Abstract

A liquid chromatographic (LC) method for the quantitative determination of telithromycin, the first member of the ketolides, which is a new class of macrolides, was developed. Analytical parameters were studied according to International Conference on Harmonization (ICH) guidelines. An Ace RP-18 octadecyl silane column (250 mm x 4.6 mm, 5 microm) maintained at 50 degrees C was used as the stationary phase, and methanol and 0.067 M potassium monobasic phosphate buffer pH 4.0 (55:45, v/v) were used as the mobile phase with UV detection at 265 nm. In forced degradation studies, the effects of acid, base, oxidation, UV light and temperature were investigated showing no interference in the drug peak. The method was linear (r=0.9999) at concentration ranging from 10.0 to 40.0 microg/mL, precise (intra-day relative standard deviation [RSD] and inter-day RSD values<2.0%), accurate (mean recovery=100.76%), specific and robust. Detection and quantitation limits were 0.0027 and 0.0082 microg/mL, respectively. The results showed the proposed method is suitable for its intended use. The validated method may be used to quantify telithromycin tablets and to determine the stability of the drug. The method is able to separate telithromycin from its degradation products and tablet excipients for its sensitivity and reproducibility. These results are in accordance with a previous microbiological assay study, which used the same tested conditions showing that the methods can be interchangeable.