Resistance of morpholino phosphorodiamidate oligomers to enzymatic degradation

Oligomers possessing the Morpholino phosphorodiamidate backbone were evaluated for resistance to a variety of enzymes and biologic fluids, A 25-mer was incubated with nucleases, proteases, esterases, and serum, and the reaction mixtures were directly analyzed by MALDI-TOF mass spectrometry, The 25-mer was completely resistant to 13 different hydrolases and serum and plasma. The excellent resistance of the Morpholino phosphorodiamidates to enzymatic attack indicates their suitability for in vivo use.