SCREENING AND CHARACTERIZATION OF BIOPHARMACEUTICALS BY HIGH-PERFORMANCE CAPILLARY ELECTROPHORESIS WITH LASER-INDUCED NATIVE FLUORESCENCE DETECTION

High-performance capillary electrophoresis (HPCE) with laser-induced n ative fluorescence (LIF) detection is used to address significant prob lems in the quality control of biopharmaceuticals. All of the biopharm aceuticals studied can be detected at subnanomolar levels with linear dynamic ranges of at least 3 orders of magnitude. HPCE/LIF can determi ne impurities in ''purified'' biopharmaceuticals present in amounts le ss than 0.01% (i. e., at 4 X 10(-11) M) that of the major component. W ith HPCE/LIF, detection sensitivity is thus no longer a concern in the assaying of active ingredients in biopharmaceutical dosage formulatio ns. The peptide mapping of biopharmaceuticals present at 1 X 10(-7) M (or an injected limit of detection of 60 amol) is presented. Also, kin etic information on the reaction of a recombinant enzyme-drug with its substrate present at the micromolar level has been extracted from ele ctropherograms acquired in real-time.