Pharmacokinetics of penicillin G procaine versus penicillin G potassium and procaine hydrochloride in horses.
OBJECTIVE
To compare the pharmacokinetics of penicillin G and procaine in racehorses following i.m. administration of penicillin G procaine (PGP) with pharmacokinetics following i.m. administration of penicillin G potassium and procaine hydrochloride (PH).


METHODS
6 healthy adult mares.


METHODS
Horses were treated with PGP (22,000 units of penicillin G/kg of body weight, i.m.) and with penicillin G potassium (22,000 U/kg, i.m.) and PH (1.55 mg/kg, i.m.). A minimum of 3 weeks was allowed to elapse between drug treatments. Plasma and urine penicillin G and procaine concentrations were measured by use of high-pressure liquid chromatography.


RESULTS
Median elimination phase half-lives of penicillin G were 24.7 and 12.9 hours, respectively, after administration of PGP and penicillin G potassium. Plasma penicillin G concentration 24 hours after administration of penicillin G potassium and PH was not significantly different from concentration 24 hours after administration of PGP. Median elimination phase half-life of procaine following administration of PGP (15.6 hours) was significantly longer than value obtained after administration of penicillin G potassium and PH (1 hour).


CONCLUSIONS
Results suggest that i.m. administration of penicillin G potassium will result in plasma penicillin G concentrations for 24 hours after drug administration comparable to those obtained with administration of PGP Clearance of procaine from plasma following administration of penicillin G potassium and PH was rapid, compared with clearance following administration of PGP.
Uboh
C E
CE
West Chester University, Department of Chemistry, PA 19382, USA.
Soma
L R
LR
Luo
Y
Y
McNamara
E
E
Fennell
M A
MA
May
L
L
Teleis
D C
DC
Rudy
J A
JA
Watson
A O
AO
D000818:Animals; D019540:Area Under Curve; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D005260:Female; D006207:Half-Life; D006736:Horses / Q000378:metabolism*; D007273:Injections, Intramuscular / Q000662:veterinary; D016018:Least-Squares Analysis; D010402:Penicillin G Procaine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D010406:Penicillins / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D018709:Statistics, Nonparametric
D010406:Penicillins; D010402:Penicillin G Procaine