Pharmacokinetics of Pilocarpine

An ion‐pair HPLC assay was established to measure pilocarpine in plasma and in urine. Half‐lives of 1 h and 30 min, respectively, were found for pilocarpine in blood and plasma after incubation at 37°C. Pilocarpine breakdown was stabilized by the addition of potassium fluoride. Pilocarpine given as a solution (5 or 10 mg) to seven subjects yielded plasma levels below the assay sensitivity of 30 ng mL in six subjects, with a peak concentration of 63 ng mL found in the remaining subject given 10 mg pilocarpine. Saliva production appeared to peak about 1 h after dosing. Between 7 and 33% of the pilocarpine was found in the urine with an elimination half‐life of pilocarpine of approximately 1 h. 1995 Royal Pharmaceutical Society of Great Britain