reported that analysis of glycopeptides by MALDI-TOF may overestimate low abundant truncated oligosaccharides due to in-source frag-mentation of the abundant oligosaccharide struc-tures.Therefore,for recombinant monoclonal antibody characterization,parallel rigorous con-trols are very important.

Characterization and a thorough understand-ing of the heterogeneity of monoclonal antibodies can be very challenging.However,the informa-tion is invaluable to understanding structure and stability of the molecule in order to engineer better molecules with good efficacy and safety. ACKNOWLEDGMENTS

The authors would like to thank Lyman G.Armes for critical review of the manuscript,and Czeslaw H.Radziejewski,Gary J.Welch and Peter Moesta for their support.

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DOI10.1002/jps JOURNAL OF PHARMACEUTICAL SCIENCES,VOL.97,NO.7,JULY2008

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