The invention provides chemical conjugates between an immunoglobulin Fab fragment and molecular entities imparting diagnostic or therapeutic utility, whereby the only sites of conjugation on the Fab fragment are one or both of the sulfhydryl groups deriving from the selective and quantitative reduction of the inter-chain disulfide bond of said Fab fragment and whereby said molecular entities imparting diagnostic or therapeutic utility have at least one free sulfhydryl-reactive group, characterized in that the conjugation stoichiometric molar ratio molecular entity to Fab fragment is in the range from 0.95 to 1.05 or in the range from 1.95 to 2.05.
The invention also provides a process for preparing said conjugates and pharmaceutical compositions thereof.
本发明提供了免疫球蛋白 Fab 片段与具有诊断或治疗作用的分子实体之间的
化学共轭物,其中 Fab 片段上的唯一共轭位点是一个或两个巯基,这些巯基来自所述 Fab 片段的链间二
硫键的选择性定量还原,并且所述具有诊断或治疗作用的分子实体具有至少一个游离的巯基反应基团,其特征在于共轭
化学计量摩尔比分子实体与 Fab 片段在 0.95至1.05或在1.95至2.05的范围内。
本发明还提供了制备上述共轭物及其药物组合物的工艺。