Pyridostigmine Bromide (PB) is a pretreatment drug used to protect against chemical warfare nerve agents.

Since the guinea pig and mouse PK experiments required the use of less than 30 µL of plasma with quantitation limits near 500 pg/mL, a highly sensitive analytical method was needed such as HPLC/MS/MS. Previous methods employed HPLC/MS, however, the method required 50 µL of plasma with a limit of quantitation of 700 pg/mL. In addition, the use of single ion monitoring subjected the assay to interferences.