Processes for preparing monomeric conjugates of calicheamicin carrier and derivative

摘要

In the present invention, there is provided a method for preparing monomeric calicheamicin derivative/carrier conjugates with higher drug loading/yield and decreased aggregation. These conjugates are prepared by incubating a calicheamicin derivative and a proteinaceous carrier in a solution comprising a non-nucleophilic, protein-compatible, buffered solution having a pH in the range from about 4.0 to 8.5 and comprising a cosolvent selected from the group consisting of propylene glycol, ethanol, DMSO, and combinations thereof, and an additive comprising at least one C6-C18 carboxylic acid having 6 to 18 carbon atoms, at a temperature ranging from about 25 degC to about 37 DegC for a period of time ranging from about 15 minutes to about 24 hours, and purifying the conjugate prepared in the step (1)¿to obtain monomeric calicheamicin derivative/carrier conjugates. Alternatively, the conjugates can be prepared by incubating the calicheamicin derivative and a proteinaceous carrier in a solution comprising a non-nucleophilic, protein-compatible, buffered solution and a cosolvent comprising t-butanol.