反应详情

The drug-linker SMCC-MDC was prepared in the following reactions: (1) 3-mercaptopropanoic acid (MPr) was reacted with N-succinimidyl 4-(maleimidomethyl)cyclohexane-1-carboxylate (SMCC) in the presence of N,N-diisopropylethylamine (DIEA), giving the MPr-SMCC at a yield of over 95%; (2) condensation of N-Me-L-Ala-MDC, which was prepared by deprotection of Fmoc-N-Me-Ala-MDC under a base piperidine in CH3CN, with MPr-SMCC in the presence of a coupling reagent EDC, giving the desired coupled product SMCC-MDC in 60-70% yield over two steps. Anti-EGFR antibody Anti-EGFR antibody was diluted to 2.5 mg/mL in solution A (50 mM potassium phosphate, 50 mM NaCl, and 2 mM EDTA, pH 6.5). SMCC-MDC was added to give a ratio of SMCC-MDC to antibody of 7:1 mole equivalent. Then dimethylacetamide (DMA) was added to 15% (v/v) to the reaction and reaction was mixed by stirring for 4 h at ambient temperature. D-Lmcc-Anti-EGFR antibody conjugate was purified from excess unreacted or hydrolyzed reagent and excess SMCC-MDC using a G25 gel filtration column equilibrated in pH 7.4 phosphate buffer (aqueous). The conjugate was then dialyzed overnight into pH 7.4 phosphate buffer (aqueous) and filtered through a 0.22 μm filter for final storage. The number of SMCC-MDC molecule per antibody molecule in the final conjugate was measured by determining absorbance of the conjugate at 252 and 280 nm and using known extinction coefficients for SMCC-MDC and antibody at these two wavelengths. A ratio of maytansinoid compound to antibody of 3.5:1.0 was normally obtained.