Pharmacokinetics of glycopyrronium in parturients

A sensitive radioreceptor assay was used to determine the pharmacokinetics of glycopyrronium 6 micrograms/kg after intramuscular (deltoid muscle) administration in eight Caesarean section patients. A fast absorption rate was found with a mean maximum plasma concentration (Cmax) of 6.3 (SD 1.5) ng/ml, a mean time to Cmax (Tmax) of 10.0 (3.8) minutes and the elimination half-life (t1) of 33.4 (1.92). The respective AUC0-8 h value was 5.61 (1.27) hours ng/ml. This dose produced a significant increase in the maternal heart rate after 10 minutes (p less than 0.05) and an antisialogogue effect after 30 minutes (p less than 0.05) of the drug injection. Almost half of drug (48.3%) was excreted into the urine within 3 hours. There were no measurable levels of glycopyrronium in the lumbar cerebrospinal fluid (CSF) after 60 minutes of drug injection. The concentrations of glycopyrronium in the umbilical venous (0.28 (0.25) ng/ml) and in the umbilical arterial (0.18 (0.11) ng/ml) plasma after 86 minutes of drug injection were low and clinically insignificant, as was the case in the amniotic fluid (0.15 (0.08) ng/ml).