Comparison of three generic vancomycin products using liquid chromatography-mass spectrometry and an online tool.

PURPOSE: Three different generic vancomycin products were compared using liquid chromatography-mass spectrometry (LC-MS) and open-access metabolomic tools.

METHODS: Single-lot samples of vancomycin hydrochloride from three different manufacturers (Hospira, APP Pharmaceuticals, and Pfizer) were reconstituted and injected into a high-resolution LC-MS system. The mass spectral fingerprints were compared for similarity of nonvancomycin B components using the XCMS Online system through Scripps University. Significance was defined as a p of ≤0.01 and a fold change of ≥1.5. The concentration of vancomycin B in each product was also measured using LC-MS on days 0, 1, 2, 4, 7, 10, and 14.

RESULTS: Qualitative comparisons of the products using the XCMS Online interface indicated the presence of significant differences among the products at the time of reconstitution; however, these variations seemed to converge after 14 days of storage. The concentration profiles of vancomycin B during refrigerated storage did not differ significantly among the three products. XCMS Online analyses revealed that the Pfizer and Hospira products were the most similar to each other.

CONCLUSION: While there were no significant differences found in the concentration of vancomycin B among Pfizer, APP, and Hospira products, there were differences in their initial mass spectral analysis after reconstitution. Liquid chromatography-tandem mass spectrometry profiles of the ions or isotopes present in the three products showed significant differences in impurities such as crystalline degradation product (CDP)-1 and CDP intermediate. After 14 days of refrigerated storage, the differences among the products converged, and fewer distinct features could be detected.