A STABILITY-INDICATING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY OF ERYTHROMYCIN ESTOLATE IN PHARMACEUTICAL DOSAGE FORMS

A high-performance liquid chromatographic (HPLC) method utilizing either ultraviolet (UV) or electrochemical detection for the analysis of erythromycin estolate in pharmaceutical dosage forms is described. Special considerations relating to the stability of the estolate moiety during sample manipulation and storage in the autosampler are discussed. The UV detector was found to be adequate for the routine analysis of dosage forms containing erythromycin estolate while the electrochemical detector provided advantages in stability studies due to its increased sensitivity and its ability to detect trace amounts of degradation products. The inclusion of oleandomycin phosphate as the internal standard greatly increased the precision of the method which was successfully employed for the analysis of individual tablet, capsule and suspension dosage forms containing varying amounts of erythromycin estolate obtained from three different manufacturers. © 1990.