Screening and characterization of biopharmaceuticals by high-performance capillary electrophoresis with laser-induced native fluorescence detection.

High-performance capillary electrophoresis (HPCE) with laser-induced native fluorescence (LIF) detection is used to address significant problems in the quality control of biopharmaceuticals. All of the biopharmaceuticals studied can be detected at subnanomolar levels with linear dynamic ranges of at least 3 orders of magnitude. HPCE/LIF can determine impurities in "purified" biopharmaceuticals present in amounts less than 0.01% (i.e., at 4 x 10(-11) M) that of the major component. With HPCE/LIF, detection sensitivity is thus no longer a concern in the assaying of active ingredients in biopharmaceutical dosage formulations. The peptide mapping of biopharmaceuticals present at 1 x 10(-7) M (or an injected limit of detection of 60 amol) is presented. Also, kinetic information on the reaction of a recombinant enzyme-drug with its substrate present at the micromolar level has been extracted from electropherograms acquired in real-time.