Determination of PMO and PPMO by LC-MS/MS in Tissue Homogenate

In PMO (phosphorodiamidate morpholino oligomers, PMO) and PPMO (Peptide-conjugated phosphorodiamidate morpholino oligomer) molecules, the five-member-ribose rings of the natural nucleic acid backbone are replaced by six-member morpholine rings. Additionally, the negatively charged phosphate linkages of natural nucleic acids are substituted by nonionic phosphorodiamidate linkages in PMOs. Those structure changes make the molecules positively charged, therefore tend to bind to surfaces such as polypropylene vials, 96-well plates, pipette tips, autosampler injection syringe, column, tubing and protein in biological matrix. The nonspecific binding leads to recovery issue and unsatisfactory peak shape and massive carryover.

 A qualified, rapid, and reproducible LC-MS/MS method was developed for the quantitative determination of PMOs and PPMOs in monkey tissue homogenate.