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Thiamphenicol (TP) pharmacokinetics were studied in Japanese quails (Coturnix japonica) following a single intravenous (IV) and oral (PO) administration at 30 mg/kg BW. Concentrations of TP were determined with HPLC and were analyzed by a noncompartmental method. After IV injection, elimination half-life (t1/2λz ), total body clearance (Cltot ) volume of distribution at steady state (Vdss ), and mean residence time (MRT) of TP were 3.83 hr, 0.19 L/hr/kg, 0.84 L/kg, and 4.37 hr, respectively. After oral administration of TP, the peak plasma concentration (Cmax ) was 19.81 μg/ml and was obtained at 2.00 hr (tmax ) postadministration. Elimination half-life (t1/2λz ) and mean absorption time (MAT) were 4.01 hr and 1.56 hr, respectively. The systemic bioavailability following oral administration of TP was 78.10%. TP therapy with an oral dosage of 30 mg/kg BW is suggested for a beneficial clinical effect in quails. more...

Pharmacokinetics of difloxacin (DF), a fluoroquinolone antibiotic, were investigated in Japanese quails (Coturnix japonica) after a single intravenous (IV) and oral (PO) administration of 10 mg/kg bodyweight. Plasma concentration profiles of DF were analyzed by a compartmental pharmacokinetic method. Following IV injection, the plasma concentration vs time profile was best described by a two-compartment open model. Elimination half-life (t1/2β), total body clearance (Cltot), volume of distribution at steady state (Vdss) and mean residence time (MRT) of DF were 5.45 ± 0.14 h, 0.22 ± 0.01 L/kg/h, 1.54 ± 0.06 L/kg and 6.92 ± 0.19 h, respectively. Following PO administration, DF was rapidly absorbed, with peak plasma concentration (Cmax) of 3.67 μg/mL attained at 1.90 h (Tmax) after administration. Absorption half-life (t1/2ab), elimination half-life (t1/2el), mean absorption time (MAT) were 0.5 h, 5.26 h and 1.11 h, respectively. The bioavailability (F) following PO administration of DF was high (84.40%). For a successful clinical effect of DF in quails, a multiple dosage regimen of 10 mg/kg bodyweight, administered orally every 24 h is recommended to maintain effective plasma concentrations with bacterial infections, in which MIC90 is more...

The present study was conducted to investigate the pharmacokinetics of tilmicosin (25 mg/kg b.wt.) following single and repeated oral administration (once daily for three consecutive days) as well as tissue residues in normal and experimentally Mycoplasma gallisepticum-infected broiler chickens. Following single administration of tilmicosin in normal chickens, the drug reached its maximum serum concentrations (Cmax) after 2.45±0.01 h of administration with value of 0.97±0.04 µg/ml. Absorption half-life (t0.5ab) of tilmicosin was 0.89±0.02 h and the elimination half-life (t0.5el) was 14.73 ±1.24 h. The repeated oral administration of tilmicosin in normal and Mycoplasma gallisepticum- infected chickens revealed a lower significant serum tilmicosin concentration after all times of sampling in infected chickens compared to those of normal chickens. Tilmicosin residues was assayed in lung, kidney, liver, heart, breast muscle, thigh muscle, fat and skin after 24, 48, 72, 96, 120 and 144 h post last dose. The results showed that the highest residue values were recorded in lung followed by liver and kidneys while the lowest values were recorded in heart. Tilmicosin residues were not detected in all tested tissues except in lung till 5th day after sessation of drug administration. However, all the tested tissues were free from tilmicosin residues after 5th day after sessation of tilmicosin administration and this suggest a withdrawal period of five days for tilmicosin in broiler chickens. In conclusion, timicosin has rapid absorption, long elimination half-life, rapid and extensive penetration from blood into tissues especially lungs. Additionally, timicosin had a short more...

The oral pharmacokinetics of three sulfonamides, sulfadimidine (pKa 7.5), sulfadiazine (pKa 6.5) and sulfanilamide (pKa 10.5), with different rates of unionization in rumen juice, were compared in Shiba goats to clarify the relationship between drug absorption profiles after their oral administration as well as their degree of unionization in the rumen. Sulfonamides were administered either into the left jugular vein or orally to five male goats at doses of 10 mg/kg body weight, using a crossover design with at least a 3-week washout period. The Tmax of sulfadimidine, sulfadiazine and sulfanilamide reached 2.0 ± 1.2, 6.0 ± 0.0, and 7.8 ± 1.6 hr, respectively, after their oral administration, and this was followed by their slow elimination due to a slow rate of drug absorption from the gastrointestinal tract. The MAT and t1/2ka of sulfadiazine (13.2 ± 2.0 and 10.9 ± 1.08 hr) were significantly longer than those of sulfanilamide (9.09 ± 1.67 and 7.46 ± 1.70 hr) and sulfadimidine (7.52 ± 0.85 and 5.17 ± 0.66 hr). These results suggest that the absorption rates of highly unionized drugs (such as sulfanilamide and sulfadimidine) from the forestomach of goats may be markedly higher than less unionized ones (such as sulfadiazine). The mean oral bioavailability of sulfadiazine was high (83.9 ± 17.0%), whereas those of sulfadimidine and sulfanilamide were low (44.9 ± 16.4% and 49.2 ± 2.11%, respectively). more...

The pharmacokinetics of acetaminophen was investigated following oral dosing to Shiba goats in order to evaluate the properties of gastric emptying. Acetaminophen was intravenously and orally administered at 30 mg/kg body weight to goats using a crossover design with a 3-week washout period. The stability of acetaminophen in rumen juice was also assessed. Acetaminophen concentrations were measured by HPLC. Since acetaminophen was stable in rumen juice for 24 hr, the extremely low bioavailability (16%) was attributed to its hepatic extensive first-pass effect. The mean absorption time and absorption half-life were unexpectedly short (4.93 and 3.35 hr, respectively), indicating its marked absorption from the forestomach, which may have been due to its smaller molecular weight. Therefore, acetaminophen was considered to be unsuitable for evaluating gastric emptying in Shiba goats. more...

Aims: The present study was designed to assess the comparative bio-equivalence of Doxysol® and Doxymed® in healthy broiler chickens after oral administration of both products in a dose of 20 mg doxycycline/kg.b.wt. Materials and Methods: Twenty broiler chickens were divided into two groups. The first group was designed to study the pharmacokinetics of Doxysol, while the 2nd group was designed to study the pharmacokinetics of Doxymed. Each broiler chickens in both groups were injected intravenously with 20 mg doxycycline/kg.b.wt. Blood samples were obtained from the wing vein and collected immediately before and at 5, 15, 30 minute, 1, 2, 4, 6, 8, 12 and 24 hours after a single intravenous or oral administration. Results: Doxycycline in both products obeyed a two compartments open model following I.V. injection in a dose of 20 mg/kg.b.wt. The disposition kinetics of Doxysol® and Doxymed® following oral administration of 20 mg doxycycline base/kg.b.wt. revealed that the maximum blood concentration [Cmax.] were 4.70 and 4.65 μg/ml and attained at [tmax.] of 1.30 and 1.40 hours, respectively. Doxycycline in Doxysol® and Doxymed® was eliminated with half-lives [t0.5(β)] equal to 1.98 and 2.31 hours, respectively. The mean systemic bioavailability of doxycycline in Doxysol® and Doxymed® after oral administration in healthy chickens was 92.57 and 88.21%, respectively. Conclusion: Doxymed® is bioequivalent to Doxysol® since Cmax test/Cmax reference and AUCtest/AUCreference ratios were 99% and 90%, respectively. more...

The purpose of this study was to evaluate the pharmacokinetics of cefquinome (CFQ) following single intravenous (IV) or intramuscular (IM) injections of 2mg/kg body weight in red-eared slider turtles. Plasma concentrations of CFQ were determined by high-performance liquid chromatography and analyzed using noncompartmental methods. The pharmacokinetic parameters following IV injection were as follows: elimination half-life (t(1/2z)) 21.73 +/- 4.95hr, volume of distribution at steady-state (V-dss) 0.37 +/- 0.11L/kg, area under the plasma concentration-time curve (AUC(0-)) 163 +/- 32ghr(-1)ml(-1), and total body clearance (Cl-T) 12.66 +/- 2.51 mlhr(-1)kg(-1). The pharmacokinetic parameters after IM injection were as follows: peak plasma concentration (C-max) 3.94 +/- 0.84g/ml, time to peak concentration (T-max) 3hr, t(1/2z) 26.90 +/- 4.33hr, and AUC(0-) 145 +/- 48ghr(-1)ml(-1). The bioavailability after IM injection was 88%. Data suggest that CFQ has a favorable pharmacokinetic profile with a long half-life and a high bioavailability in red-eared slider turtles. Further studies are needed to establish a multiple dosage regimen and evaluate clinical efficacy. more...

Background: The present study was designed to assess the comparative bioequivalence of Biocillin® and Atcomox87%® in healthy broiler chickens after oral administration of both products in a dose of 20 mg amoxicillin base/kg.b.wt. Methods: Twenty-four broiler chickens were divided into two groups. The first group was designed to study the pharmacokinetics of Biocillin®, while the 2nd group was designed to study the pharmacokinetics of Atcomox87%®. Each broiler chicken in both groups was injected intravenously with 20 mg amoxicillin pure standard/kg.b.wt. After 15 days both groups taken orally Biocillin® and Atcomox87%®, respectively. Blood samples were obtained from the wing vein and collected immediately before and at 0.08, 0.16, 0.25, 0.5, 1, 2, 4, 8, 12 and 24 hours after a single intravenous or oral administration. Results: Amoxicillin in both products obeyed a two compartments open model following I.V. injection. The disposition kinetics of Biocillin® and Atcomox87%® following oral administration of 20 mg amoxicillin base/kg.b.wt. revealed that the maximum blood concentration [C max ] were 10.79 and 10.30 μg/ml and attained at [t max ] of 0.90 and 0.86 hours, respectively. The mean systemic bioavailability of amoxicillin in Biocillin® and Atcomox 87%® after oral administration in healthy chickens was 64.15 and 65.54%, respectively. Conclusions: Atcomox 87%® is bioequivalent to Biocillin® since the ratios of Cmax, AUC0-24 and AUC0-∞ (T/R) were 0.95, 0.91 and 0.90 respectively. These are within the bioequivalence acceptance range. Biocillin® and Atcomox87%® are therefore bioequivalent and interchangeable. more...

The pharmacokinetics (after single intravenous and oral dose) and tissue residues (orally and daily for five days) of cephradine (20 mg/kg b.wt.) were investigated in healthy and experimentally E.coli infected broiler chickens. Following single intravenous injection to healthy chickens, cephradine obeyed a two compartments open model and the elimination half-life (t1/2β), volume of distribution (Vdss) and total body clearance (CLtot) of cephradine were 2.93 h, 321.5 ml/kg and 0.08 L/h/kg, respectively. Following single oral administration of cephradine to healthy chickens, the peak serum concentration (Cmax) of it was 26.7 µg/mL and achieved (Tmax) at 2.41 h. The oral bioavailability of cephradine was 87.7%. Cephradine was assayed in kidney, liver, heart, gizzard, spleen, breast muscle, thigh muscle and skin after 24, 48, 72, 96 and 120 h after last dose. On conclusion, cephradine is a good choice for treatment of colisepticemia in chickens due to its higher oral bioavailability and distribution. more...

1. The pharmacokinetics and bioavailability of levofloxacin in turkeys were investigated after a single intravenous (IV), intramuscular (IM) and oral (PO) administration of 10 mg/kg body weight. 2. The concentrations of levofloxacin in plasma samples were assayed using a microbiological assay method and pharmacokinetic parameters were calculated by non-compartmental analysis. 3. Following IV administration, the elimination half-life (t0.5(β)), volume of distribution at steady state (Vdss) and total body clearance (Cl) were 4.49 h, 1.31 l/kg and 0.23 l/h/kg, respectively. 4. After single IM and PO administrations at the same dose, levofloxacin was rapidly absorbed as indicated by an absorption half-life (t0.5ab) of 1.02 and 0.76 h, respectively; maximum plasma concentrations (Cmax) of 5.59 and 5.15 μg/ml were obtained at a maximum time (Tmax) of 2 h for both routes and levofloxacin bioavailability (F) was 96.5 h and 79.9% respectively after IM and PO administration. In vitro plasma protein binding of levofloxacin was 24.3%. 5. Based on these pharmacokinetic parameters, a dose of 10 mg/kg body weight given intramuscularly or orally every 24 h in turkeys can maintain effective plasma concentrations with bacterial infections with (minimum inhibitory concentration) MIC90 > 0.1 μg/ml. more...

The pharmacokinetics aspects of levofloxacin were studied in healthy and experimentally renal damaged Muscovy ducks after single intravenous (IV) and oral (PO) dose of 10 mg kg−1 bwt. Following IV administration, elimination half-life (t1/2(β)) and mean residence time (MRT) were longer in renal damaged ducks than in healthy ones. Total clearance(Cltot)in renal damaged ducks (0.20 L kg−1 h−1) was significantly lower as compared to that in healthy ones (0.41 L kg−1 h−1). Following PO administration, the peak serum concentration(Cmax)was higher in renal damaged than in healthy ducks and was achieved at maximum time(tmax)of 2.47 and 2.05 h, respectively. The drug was eliminated (t1/2(el)) at a significant slower rate (3.94 h) in renal damaged than in healthy ducks (2.89 h). The pharmacokinetic profile of levofloxacin is altered in renal damaged ducks due to the increased serum levofloxacin concentrations compared with that in clinically healthy ducks. Oral administration of levofloxacin at 10 mg kg−1 bwt may be highly efficacious against susceptible bacteria in ducks. Also, the dose of levofloxacin should be reduced in renal damaged ducks. Pharmacokinetic/pharmacodynamic integration revealed significantly higher values forCmax/MIC and AUC/MIC ratios in renal damaged ducks than in healthy ones, indicating the excellent pharmacokinetic characteristics of levofloxacin in renal damaged ducks. more...

Influence of Aeromonas hdrophilia Infection on the Disposition Kinetic of Norfloxacin in Goldfish (Carassius auratus) The pharmacokinetic of norfloxacin (10 mg kg-1) following single intravenous (IV) and oral administration (PO) in healthy goldfish were investigated. Also, repeated (PO) administration of norfloxacin in healthy and experimentally Aeromonas hydrophilia infected goldfish was studied. Following IV administration, norfloxacin obeyed a two compartments open model, distribution half-life (t1/2(α)) equal to 0.12 h, volume of distribution (Vdss) was 1.01 L kg-1, elimination halflife (t1/2(β)) was 4.30 h and total body clearance (CLtot) was 0.17 L kg-1h-1. Following PO administration, norfloxacin was rapidly and efficiently absorbed through gastrointestinal tract as the absorption half-life (t1/2(ab)) was 0.84 h. more...

The comparative pharmacokinetic profile of cefquinome was studied in sheep and goats following repeated intramuscular (IM) administrations of 2 mg/kg body weight. Cefquinome concentrations in serum were determined by microbiological assay technique using Micrococcus luteus (ATCC 9341) as test organism. Following intramuscular injection of cefquinome in sheep and goats, the disposition curves were best described by two-compartment open model in both sheep and goats. The pharmacokinetics of cefquinome did not differ significantly between sheep and goats; similar intramuscular dose rate of cefquinome should therefore be applicable to both species. On comparing the data of serum levels of repeated intramuscular injections with first intramuscular injection, it was revealed that repeated intramuscular injections of cefquinome have cumulative effect in both species sheep and goats. The in vitro serum protein-binding tendency was 15.65% in sheep and 14.42% in goats. The serum concentrations of cefquinome along 24 h after injection in this study were exceeding the MICs of different susceptible microorganisms responsible for serious disease problems. These findings indicate successful use of cefquinome in sheep and goats. more...

Background: Pharmacokinetic study of a commercial tylosin-doxycycline combination product (D-Tylo50/25®) was conducted in broiler chickens following intravenous (IV) and oral (PO) administration at doses of 50 mg/kgb. wt. (tylosin) and 25 mg/kg b. wt. (doxycycline).Methods: Serum drug concentrations were determined by a validated high performance liquid chromatography (HPLC) using UV detection.Results: A rapid and nearly complete absorption of both drugs with a mean PO bioavailability of 89.16% (tylosin) and 94.30% (doxycycline), prolonged elimination half-lives, and high tissue penetration with steady state volume of distribution of 6.73L/kg (tylosin) and 5.51L/kg (doxycycline) were observed. Tissue residues were studied following oral administration of each drug alone for fiveconsecutive days and blood and tissue samples were obtained for 10 days after the last dose. Residues of tylosin and doxycyclines showed that kidney, liver and lung contained highest drug residues and completely disappeared from those tissues at 5 and 6 days after the last oral dose, respectively. The efficacies of D-Tylo50/25® and other antibiotics (tiamulin and oxytetracyline) were investigated in broiler chicks experimentally infected by Mycoplasma gallisepticum.Conclusions: The pharmacokinetics of both drugs was characterized by a rapid and complete absorption, extensive tissue distribution and slow elimination. D-Tylo50/25® is more effective than tiamulin and oxytetracycline against Mycoplasma gallisepticum infection in broilers. more...

The aim of present study was to determine the pharmacokinetics and tissue residues of tilmicosin phosphate (tilmicoral®) as well as its in vitro and in vivo evaluation for control of Mycoplasma gallisepticum (MG) infection in broiler chickens. Pharmacokinetics (single oral dose) and tissues residues (daily for five days) of tilmicosin (25 mg/kg b.wt) in broilers were investigated. Peak plasma concentration of tilmicosin was 1.25±0.0.09 μg/mL and achieved at 3.15±0.34 h. Elimination half-life was long (44.3±7.22 h) and Vdarea was large (1.25±0.082 L/kg). Residue study revealed a good distribution and penetration of tilmicosine in lung, liver, kidney and muscles. Tilmicosin could not be detected in all tested tissues (except in lung) at 6 days after last administration. The MIC of tilmicosin and tylosin against MG were 0.054 and 0.319 μg/mL, respectively. MG infected chickens and treated by tilmicosin or tylosin showed a significant (p more...

1. The pharmacokinetics of levofloxacin were investigated in Japanese quails after a single dose of 10 mg/kg BW, given either intravenously or orally. 2. Following intravenous administration, the mean value of distribution at steady state (Vd(ss)), total body clearance (Cl(tot)) and mean residence time (MRT) of levofloxacin were 1·25 l/kg, 0·39 l/h/kg and 2·72 h, respectively. 3. Following oral administration of levofloxacin, the peak plasma concentration (C(max)) was 3·31 µg/ml and was achieved at a maximum time (T(max)) of 2 h. Mean residence time (MRT), mean absorption time (MAT) and bioavailability were 4·26 h, 1·54 h and 69·01%, respectively. In vitro plasma protein binding of levofloxacin was 23·52%. 4. Based on pharmacokinetic and pharmacodynamic integration, an oral dose of 10 mg/kg levofloxacin for every 12 h is recommended for a successful clinical effect in quails. more...

The pharmacokinetic profile of cefotaxime following a single intravenous (IV) and intramuscular (IM) injection was studied in Muscovy ducks. Cefotaxime was given at a dose rate of 25 mg/kg b.wt. for both routes. After IV injection, the plasma levels of cefotaxime estimated at 0.08 h was 70.87 μg/ml, which declined gradually and cefotaxime was detected up to 10 h (0.59 μg/ml). The mean values of CL, Vdss and t1/2β of cefotaxime in muscovy ducks were 0.22 l/kg/h, 0.51 l/kg and 1.81 h, respectively. After IM injection, maximum plasma concentration (Cmax) was (14.72 μg/ml), time of maximal plasma concentration (tmax) was (2.3 h) and elimination half-life (t1/2el)was (1.77 h). Bioavailability following IM injection was 79.61%, and in vitro protein binding percent was 31.48%. A recommended IM dosage for cefotaxime in muscovy ducks would be 30 mg/kg b.wt., repeated at 12 h intervals will provide a therapeutic plasma concentrations exceeding the MIC≤0.5 µg/ml for most susceptible pathogens in ducks. more...

The pharmacokinetics of norfloxacin was studied following repeated intramuscular injections in normal and experimentally infected goats. The serum concentrations of norfloxacin following repeated intramuscular injections of 10 mg/kg.b.wt. once daily for five consecutive days, peaked 4 hours after each intramuscular dose with lower significant values recorded in experimentally infected goats than in normal ones. Urine and milk concentrations of norfloxacin were decreased significantly in infected than in normal goats following repeated intramuscular injections. Following a single intravenous injection of norfloxacin in normal goats, serum concentration-time curve was best described by a two compartments open model with elimination half life (t0.5(β)=5.96 h), volume of distribution (Vd=0.42 L/kg) and total clearance of the drug (CLtot=0.18 ml/kg/min). The mean systemic bioavailability of norfloxacin following intramuscular injection in normal goats was 70.04%. The extent of serum protein binding of norfloxacin in goats was 14.07%. Following intramuscular injection of 10 mg/kg.b.wt of norfloxacin for 5 consecutive days, norfloxacin showed a cumulative behaviour in serum, urine and milk of goats. Results of this study indicated that norfloxacin was useful for treatment of urinary tract infections and mastitis in goats. more...