Patent ID: 7943387

Claim:
A method for the determination of the amount of self-aggregation of therapeutic proteins comprising the steps of: (a) contacting a mixture of monomeric and of non-covalently aggregated therapeutic proteins with a crosslinking reagent or a crosslinking reagent mixture of at least one member selected from the group consisting of imidoesters, N-hydroxysuccinimide esters, maleimides, haloacetates, pyridyl disulfides, hydrazides, carbodiimides, aryl azides, isocyanates, and vinyl sulfones, to form a crosslinked mixture of covalently stabilized therapeutic protein aggregates; (b) analyzing the intact ions formed from the protein monomers and aggregates in the crosslinked mixture of step (a) by High-Mass MALDI ToF mass spectrometry equipped with a high-mass detector giving low saturation and high sensitivity in a mass range higher than 200 kDa; and (c) determining directly the amount of aggregation by comparing the mass peaks with a pre-established calibration curve.