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Bayesian‐based withdrawal estimates using pharmacokinetic parameters for two capsaicinoid‐containing products administered to horses
Author(s) -
Robinson Mary A.,
Stefanovski Darko,
You Youwen,
Boston Raymond C.,
Soma Lawrence R.
Publication year - 2021
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/jvp.12939
Subject(s) - pharmacokinetics , capsaicin , oral administration , absorption (acoustics) , chemistry , pharmacology , medicine , receptor , physics , acoustics
Capsaicinoids deter horses from chewing on bandages and are applied topically to provide analgesia to musculoskeletal injuries. They are banned during competition due to their nerve blocking properties. The pharmacokinetics of oral (PO) and direct gastric administration via nasogastric tube (NG), or topical (TOP) administration of two capsaicinoid‐containing products were investigated, and the withdrawal times required prior to competition were estimated. Capsaicin (CAP) and dihydrocapsaicin (DCAP) were quantified in plasma, and both compounds were best described by a delayed absorption two compartment elimination model following PO administration and by a first order absorption one compartment elimination model following TOP administration. Capsaicin and DCAP could not be quantified in most samples following NG administration. Following PO administration, the time to maximum plasma concentration ( T max ) for CAP and DCAP was 0.25 (0.08–0.50) hr. Following TOP application, the Tmax for CAP and DCAP was 4 (2–6) and 5 (3–12) hr, respectively. By 8 hr post‐PO administration and 36 hr post‐TOP application, CAP and DCAP were below the lower limit of quantification. Capsaicin and DCAP were not detected in urine samples. Withdrawal times were predicted using the 99.99% credibility interval limits of the pharmacokinetic parameters calculated with Bayesian estimation.