Pharmacokinetics of glycopyrronium in parturients

Summary A sensitive radioreceptor assay was used to determine the pharmacokinetics of glycopyrronium 6 μg/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 (Tl 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 < 0.05) and an antisialogogue effect after 30 minutes (p < 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).