IMPROVED SYNTHESIS AND CHARACTERIZATION OF A HYDRAZIDE DERIVATIVE OF DIETHYLENETRIAMINEPENTAACETIC ACID FOR SITE-SPECIFIC LABELING OF MONOCLONAL-ANTIBODIES WITH IN-111

The monohydrazide derivative of diethylenetriaminepentaacetic acid, (2 )NCH2CH2N(CH2COOH)CH2CH2N(CH2COOH)(CH2CO.NHNH2), is a bifunctional che lator designed for attaching the radiometal In-111 selectively to the carbohydrate side chains of pre-oxidised monoclonal antibodies. A simp le synthesis of this chelator (from diethylenetriaminepentaacetic acid cyclic anhydride and hydrazine), and its purification and chemical ch aracterisation, are described. Rabbit IgG was oxidised with periodate, and the aldehyde groups thus generated were reacted with the linker f orming a conjugate that was readily labelled in high yield and purity with In-111. Copyright (C) 1996 Elsevier Science Ltd