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

Since the guinea pig PK experiments required the use of less than 30 µL of plasma with quantitation limits near 100 pg/mL, a highly sensitive analytical method was needed such as HPLC/MS/MS. Previous methods developed at Alturas (1) had limits of quantitation of only 500 pg/mL. Thus improvements in the method are needed.