The pharmacokinetics of glycopyrrolate in Standardbred horses

Abstract

The disposition of plasma glycopyrrolate (GLY) is characterized by a three-compartment pharmacokinetic model after a 1-mg bolus intravenous dose to Standardbred horses. The median (range) plasma clearance (Clp), volume of distribution of the central compartment (V1 ), volume of distribution at steady-state (Vss), and area under the plasma concentration-time curve (AUC0-inf ) were 16.7 (13.6-21.7) mL/min/kg, 0.167 (0.103-0.215) L/kg, 3.69 (0.640-38.73) L/kg, and 2.58 (2.28-2.88) ng*h/mL, respectively. Renal clearance of GLY was characterized by a median (range) of 2.65 (1.92-3.59) mL/min/kg and represented approximately 11.3-24.7% of the total plasma clearance. As a result of these studies, we conclude that the majority of GLY is cleared through hepatic mechanisms because of the limited extent of renal clearance of GLY and absence of plasma esterase activity on GLY metabolism. Although the disposition of GLY after intravenous administration to Standardbred horses was similar to that in Thoroughbred horses, differences in some pharmacokinetic parameter estimates were evident. Such differences could be attributed to breed differences or study conditions. The research could provide valuable data to support regulatory guidelines for GLY in Standardbred horses.

Dexamethasone serum concentrations after intravenous administration in horses during race training

“…No difference was found among the different racing breeds and disciplines which permitted pooling of the data for the purpose of calculating a 48 h threshold. Different racing breeds have previously been shown to exhibit some different pharmacokinetic parameters for glycopyrrolate (Rumpler et al, 2014), differences that may be associated with differences in study design, pharmacogenetics, or physiologic differences based on characteristics such as renal or splanchnic blood flow associated with the type of exercise. In this study, no effects of different breed or training regimes were evident for either the 48 or 72 h time DXM serum concentrations.…”

Diagnostic Approach to Nephrotoxicosis with Vitamin K3 in Draft Horses Based on iNOS and Selective Urinary Variables

“…MG122050 (Bohuon, 1957). Furthermore, creatinine clearance was calculated by dividing the volume urine × creatinine urine on creatinine serum ×1,440 (Rumpler et al, 2013). Serum iNOS activity was measured using the technique previously applied by Bredt et al (1991).…”

Variability in plasma concentrations of methylprednisolone 6 days after intrasynovial injection of methylprednisolone acetate in racing horses: A field study

“…The regulated population of racing horses that receive MP acetate may have injections into joints other than the antebrachiocarpal joint, and is comprised of horses other than Thoroughbreds. In the case of at least one therapeutic medication, glycopyrrolate, pharmacokinetic properties differ between Thoroughbreds and Standardbreds .…”