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A study of the disposition of procaine penicillin G in feedlot steers following intramuscular and subcutaneous injection
Author(s) -
PAPICH M. G.,
KORSRUD G. O.,
BOISON J. O.,
YATES W. D. G.,
MACNEIL J. D.,
JANZEN E. D.,
COHEN R. D. H.,
LANDRY D. A.
Publication year - 1993
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/j.1365-2885.1993.tb00178.x
Subject(s) - cmax , penicillin , procaine , subcutaneous injection , intramuscular injection , chemistry , pharmacokinetics , feedlot , zoology , medicine , anesthesia , antibiotics , pharmacology , biochemistry , biology
The disposition of an aqueous suspension of procaine penicillin G (300 000 U/ mL) was studied in feedlot steers. Four groups of three steers were used. Steers in groups 1 and 2 received procaine penicillin G once daily for 5 days intramuscularly (i.m.) at a dose of 24 000 U/kg (group 1) or of 66 000 U/kg (group 2). The injection on the last day was administered in the gluteal muscle. Steers in group 3 (i.m. neck injection) and group 4 [subcutaneous (s.c.) injection] each received a single dose of procaine penicillin G at a dose of 66 000 U/kg. From every animal, after the last injection in groups 1 and 2 and following the single injection in groups 3 and 4, a series of blood samples was taken at fixed time intervals. The plasma from these samples was analysed for penicillin G by a high performance liquid chromatography (HPLC) assay in order to determine the disposition of penicillin. The maximum plasma concentration (C max ) and the area under the curve ( AUC ) were significantly different between groups 1 and 2, but we found no difference in the disappearance rate constant between these two groups. Group 4 single s.c. injections produced a lower mean C max (1.85 ± 0.27 ng/mL) than the mean C max (4.24 ± 1.08 μg/mL) produced in group 3 by i.m. injections into the neck muscle or the mean C max (2.63 ± 0.27 μg/mL) produced in group 2 by i.m. injections into the gluteal muscle. However the mean C max produced by i.m. injections into the neck muscles (group 3) was higher than the mean C max produced by i.m. injections into the gluteal muscle (group 2). Additionally, the disappearance t ½ , was longer (18.08 h) in group 4 following the s.c. injection and shorter (8.85 h) in group 3 following the i.m. neck injection, than the t ½ following administration of the same dose i.m. into the gluteal muscle (15.96 h) in group 2. In this study, when procaine penicillin G was injected into the gluteal muscle, doses of 66 000 U/kg were necessary to produce plasma concentrations that were above a minimum inhibitory concentration (MIC) for penicillin G of 1.0 μg/mL as compared to doses of 24 000 U/kg.