الفهرس 
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Abstract
In the present work, the pharmacokinetic profiles of gentamicin and amoxicillin were studied following intramus-cular and intrauterine administration in Post-Partum normal and endometritic cows. Bioavailability of both drugs were calculated in normal cows after intramuscular and intrauterine administration. The - in vitro - protein binding percent was determined, as well as the efficacy of both used antibi-otics for the treatment of endometritic cows were recorded. The concentrations of gentamicin and amoxicillin in serum, urine, and milk were assayed microbiologically.
Gentamicin:
Following a single intramuscular injection of gentamicin (5 mg/kg.b.wt.), a maximum serum concentration was recorded at 1 h., with half-life of absorption [t0.5( ab)] valued with 0.28 and 0.21 h, in normal and endometritic cows respectively. The elimination half-lives [t0.54)] were 2.52 h (normal cows) and 2.71 h (endometritic cows). The mean peak urine concentration of gentamicin occured 4 h. Post-injection with values fo 645 and 366 in normal and endometritic cows respec-tively, while its peak concentration in milk occured 2h. post-injection, with mean values of 1.10 and 0.71 ug/ml for normal and endometritic cows respectively. Following a single intravenous dosage (5 mg/kg.b.wt.) in normal cows previously given gentamicin intramuscularly, the drug obayed a two-compartments open model with half-life of distribution [t0.5(N:)] of 0.13 h., [Vic] was equal to 59.06 ml/kg. . The [Vd(area)] and [Vdss] were 106 and 103 ml/kg./min. The mean systemic bioavailability following intramuscular dose was 70% . The mean peak urine and milk
concentrations of gentamicin were detected 1 h. post-intrav-enous injection with values of 705 and 1.02 ug/ml respect- ively. During repeated intramuscular injections ( 5mg/kg.b.wt. 3 times daily for three consecutive days.), the highest serum concentrations of gentamicin occurred 1hour post each dose in normal and endometritic cows with absorption half-lives [t0.5 (ab)] ranged from 0.23 to 0.30 h. (normal cows) and from 0.21 to 0.29 h.(endometritic cows). The elimination half-lives [to.5(13)] ranged from 2.51 to 2.95 h in normal cows and from 2.71 to 3.29 h in endometritic cows. Following a single intrauterine administeration (4 mg/kg-.b.wt.), gentamicin reached its maximum concentration in serum 2 h. post- administration with absorption half-life [t0.5(ab)] of 0.52 and 0.63 h. in normal and endometritic cows respectively. The elimination half-life [t0.5(1)] was 6.23 h. (normal cows) and 2.27 h. (endometritic cows). The mean peak urine and milk conentrations occured 4h. post-administration with values of 366 and 0.71 ug/ml respec- tively. Following a single intravenous injection (5 mg/kg.b. wt) in normal cows previously given gentamicin intrauterinally. The half-life of distribution [t0.5(abc)] was 0.16 h. [Vic], [Vd(area)], [Vdss] were 62, 103, and 101 ml/kg. respectively. [CLtot.] was 0.43 ml/kg/min. and the mean systemic bioavaili-ability after intrauterine administration was 36%. The mean peak urine and milk concentrations occurred 1 hour post-intravenous injection with values of 655 and 0.95 ug/ml, respectively. During repeated intrauterine administration of gentam-icin (4 mg/kg.b.wt. once daily for three consecutive days.) revealed that the highest serum concentrations occurred 2 hours. after each dose with absorption half-lives [t0.5(ab)] ranged from 0.47 to 0.52 h. (normal cows) and from 0.57 to 0.68 h (endometritic cows). The elimination half-lives [t0.5(p)] ranged from 4.62 to 6.37 h (normal cows) and from 2.16 to 2.8 (endometritic cows). The-in vitro-protein binding percent of gentamicin was 15.85% and gentamicin treated 87.5% of the endometritic cows by both intrauterine and intramuscular administrations. Amoxicillin:
Following a single intramuscular dose of amoxicillin (10 mg/kg.b.wt.), the highest serum concentration occured lh. post-injection with values of 12 and 10 ug/ml in normal and endometritic cows respectively. The absorption half-
lives [t0.5( ab)] were 0.44 h. (normal cows) and 0.33 h. ( endome-tritic cows). The elimination half-lives were 3.19 h. (normal cows) and 3.22 h. (endometritic cows). The mean peak urine concentration occured 2h. post-injection with values of 282 ug/ml (normal cows) and 237 ug/ml (endometritic cows). The peak milk concentration occured 2h. post-injection with a mean values of 0.62 and 0.59 ug/ml, in normal and endometritic cows respectively.
Following a single intravenous dose (10 mg/kg.b.wt) in normal cows previously given amoxicillin intramuscularly, the drug followed a two-compartments open model with distribu-tion half-life [t0.5(0,c)] equal to 0.40 h. The [Vlc], [Vd area] and [Vdss] were 307, 550, and 282 ml/kg. respectively. The elimination half-life [t0.5(p)] was 4.45 h. and [CLtot] was 1.46 ml/kg/min., the mean systemic bioavailability after intramuscular injection was 63% . The mean peak urine and milk concentrations occured lh. post-injection with values of 278 and 0.69 ug/ml respectively. During repeated intramuscular injections (10 mg/kg.b.wt. 3 times daily for three consecutive days.), amoxicillin peaked in serum lh. after each dose with absorption half-lives [t0.5_ (ab)] ranged from 0.29 to 0.44 h. (normal cows) and from 0.23 to 0.33 h. (endometritic cows), while the elimination half-lives [t0.5(3)] ranged from 3.19 to 4.38 h. (normal cows) and from 3.22 to 4.61 h. (endometritic cows).
Following a single intrauterine administration (10 mg/kg.b.wt), amoxicillin reached its highest concentration in serum about 4 h. post-administeration with half-life of absorption [t0.5 (alp)] equal to 1.10 and 1.13 h. in normal and endometritic cows respectively. The elimination half-life [t0.5(8)] equal to 7.59 h (normal cows) and 7.24 (endometr- itic cows). The peak urine concentration occured 4h. post-administration with values of 250 and 211 ug/ml for normal and endometritic cows respectively. Amoxicillin concentration in milk peaked 4 h. post- administration with values of 0.53 and 0.49 ug/ml in normal and endometritic cows respectively.
Following a single intravenous injection (10 mg/kg.b.wt) in normal cows previously given amoxicillin intrauterinally, the drug obayed a two-compartments open model with distribu-tion half-life [t0.5(0‹, )] of 0.22 h., [V1c],[Vd( area)] and vdss] were 304, 494, and 488 ml/kg. respectively. The elimin- ation half-life [to.5(3)] was 4.03 h. and [Cltot.] was 1.45 ml/kg/min. The mean systemic bioavailability following intrau-terine administration was 64%. The mean peak urine and milk concentrations occured 1 h. post-injection with values of
300 and 0.66 ug/ml respectively.
During repeated intrauterine administrations of amoxici-llin (10 mg/kg.b.wt. twice daily for three consecutive days.), the drug peaked in serum 4 hours after each dose with absorp-tion half-lives [t0.5(ab)] ranged from 1.10 to 1.39 h. (normal cows) and from 1.13 to 1.37 h. (endometritic cows) . The elimination half-lives [t0•5(3)] ranged from 6 to 8 h. (normal cows) from 7 to 8 h. (endometritic cows).
The-invitro-protein binding percent of amoxicillin was 20.01% and amoxicillin treated 62.5% of endometritic cows by both intrauterine and intramuscular administrations.