Age-related intramuscular pharmacokinetics of cefquinome in sheep

Age-related changes in the pharmacokinetics of meloxicam after intravenous administration in sheep

The pharmacokinetics of meloxicam was studied in 1-, 6-, and 12-month-old sheep following a single intravenous (i.v.) dose of 1 mg/kg. The experiments were carried out when the Romanov sheep were 1 month old (7.93 ± 0.91 kg), 6 months old (27.47 ± 4.91 kg), and 12 months old (37.10 ± 3.64 kg). Meloxicam concentration in plasma was determined by high-performance liquid chromatography and the data collected were evaluated by non-compartmental kinetic analysis. Meloxicam was detected in the plasma up to 72 h following i.v. administration in all age groups. The volume of distribution at steady state (Vdss ) and total body clearance (ClT ) were significantly higher in 1-month-old (304.87 mL/kg and 16.57 mL/h/kg) than in 12-month-old (193.43 mL/kg and 10.50 mL/h/kg) sheep. The area under the concentration-time curve from 0 to 72 h value of meloxicam was lower in 1-month-old (58.51 h*μg/mL) compared to 12-month-old (92.59 h*μg/mL) sheep. There was no difference in t1/2ʎz value in different age groups. The body extraction ratio values for meloxicam ranged from 0.0186 to 0.0719 after i.v. administration in all age groups. Meloxicam showed an increase in plasma concentration and a decrease in Vdss and ClT in 12-month-old compared to 1-month-old sheep. Compared to 1-month-old and 12-month-old sheep, there was no difference in these parameters in 6-month-old sheep. Because the age of sheep has an influence on the pharmacokinetics of meloxicam, dosage apparently may need to be adjusted for age.

Pharmacokinetic evaluation of cefquinome in febrile goats following intravenous administration

Pharmacokinetics of cefquinome was studied in febrile female goats following its intravenous (IV) administration at the dose rate of 2 mg/kg body weight. The fever was induced by administration of Escherichia coli lipopolysaccharide (lμg/kg body weight). Cefquinome concentration in plasma of goats was estimated using HPLC. The drug was detected upto 24 h in febrile goats. The disposition kinetics of the drug was described by twocompartment open model. PK-PD indices; AUC24h/MIC, Cmax/MIC, T>MIC were calculated by integrating in-vivo PK data with earlier generated MIC data against Pasteurella (P.) multocida. A favourable PK and PK-PD indices suggested that the dose of 2 mg/kg/24 h of cefquinome would be effective clinically to treat goats affected with P. multocida infections.

Pharmacokinetic and pharmacodynamic integration for optimal dosage of cefquinome against Streptococcus equi subsp. equi in foals

Cefquinome is administered in horses for the treatment of respiratory infection caused by Streptococcus equi subsp. zooepidemicus, and septicemia caused by Escherichia coli. However, there have been no attempts to use cefquinome against Streptococcus equi subsp. equi (S. equi), the causative agent of strangles. Hence the objective of this study was to calculate an optimal dosage of cefquinome against S. equi based on pharmacokinetics and pharmacodynamics integration. Cefquinome (1.0 mg/kg) was administered by intravenous and intramuscular routes to six healthy thoroughbred foals. Serum cefquinome concentrations were determined by high-performance liquid chromatography. The in vitro and ex vivo antibacterial activity were determined from minimum inhibitory concentrations (MIC) and bacterial killing curves. The optimal dosage was calculated from the integration of pharmacokinetic parameters and area under the curve (AUC_24h/MIC) values. Total body clearance and volume of distribution of cefquinome after intravenous administration were 0.06 L/h/kg and 0.09 L/kg, respectively. Following intramuscular administration, a maximum concentration of 0.73 μg/mL at 1.52 h (T_max) and a systemic bioavailability of 37.45% were observed. The MIC of cefquinome against S. equi was 0.016 μg/mL. The ex vivo AUC_24h/MIC values representing bacteriostatic, and bactericidal activity were 113.11, and 143.14 h, respectively. Whereas the %T > MIC for bactericidal activity was 153.34%. In conclusion, based on AUC_24h/MIC values and pharmacokinetic parameters, cefquinome when administered by intramuscularly at a dosage of 0.53 mg/kg every 24 h, would be effective against infection caused by S. equi in foals. Further studies may be necessary to confirm its therapeutic efficacy in a clinical environment.

Pharmacokinetics and bioavailability of cefquinome and ceftriaxone in premature calves

The aim of this study was to evaluate the pharmacokinetics and bioavailability of cefquinome (CFQ) and ceftriaxone (CTX) following intravenous (IV) and intramuscular (IM) administrations in premature calves. Using a parallel design, 24 premature calves were randomly divided into the two antibiotic groups. Each of the six animals in the first group received CFQ (2 mg/kg) through IV or IM administration. The second group received CTX (20 mg/kg) via the same administration route. Plasma concentrations of the drugs were analyzed by high-performance liquid chromatography and noncompartmental methods. Mean pharmacokinetic parameters of CFQ and CTX following IV administration were as follows: elimination half-life (t_1/2λz ) 1.85 and 3.31 hr, area under the plasma concentration-time curve (AUC_0-∞ ) 15.74 and 174 hr * μg/ml, volume of distribution at steady-state 0.37 and 0.45 L/kg, and total body clearance 0.13 and 0.12 L hr^-1  kg^-1 , respectively. Mean pharmacokinetic parameters of CFQ and CTX after IM injection were as follows: peak concentration 4.56 and 25.04 μg/ml, time to reach peak concentration 1 and 1.5 hr, t_1/2λz 4.74 and 3.62 hr, and AUC_0-∞ 22.75 and 147 hr * μg/ml, respectively. The bioavailability of CFQ and CTX after IM injection was 141% and 79%, respectively. IM administration of CFQ (2 mg/kg) and CTX (20 mg/kg) can be recommended at 12-hr interval for treating infections caused by susceptible bacteria, with minimum inhibitory concentration values of ≤0.5 and ≤4 μg/ml, respectively, in premature calves. However, further research is indicated to assess the pharmacokinetic parameters following multiple doses of the drug in premature calves.

Pharmacokinetics of cefquinome after single and repeated subcutaneous administrations in sheep

The purpose of this study was to determine the pharmacokinetics of cefquinome (CFQ) following single and repeated subcutaneous (SC) administrations in sheep. Six clinically healthy, 1.5 ± 0.2 years sheep were used for the study. In pharmacokinetic study, the crossover design in three periods was performed. The withdrawal interval between the study periods was 15 days. In first period, CFQ (Cobactan, 2.5%) was administered by an intravenous (IV) bolus (3 sheep) and SC (3 sheep) injections at 2.5 mg/kg dose. In second period, the treatment administration was repeated via the opposite administration route. In third period, CFQ was administrated subcutaneously to each sheep (n = 6) at a dose of 2.5 mg/kg q. 24 hr for 5 days. Plasma concentrations of CFQ were measured using the HPLC-UV method. Pharmacokinetic parameters were calculated using non-compartmental methods. The elimination half-life and mean residence time of CFQ after the single SC administration were longer than IV administration (p < 0.05). Bioavailability (F%) of CFQ following the single SC administration was 123.51 ± 11.54%. The area under the curve (AUC_0-∞ ) and peak concentration following repeated doses (last dose) were higher than those observed after the first dose (p < 0.05). CFQ accumulated after repeated SC doses. CFQ can be given via SC at a dose of 2.5 mg/kg every 24 hr for the treatment of infections caused by susceptible pathogens, which minimum inhibitory concentration is ≤1.0 μg/ml in sheep.

Pharmacokinetics of cefquinome in crucian carp (Carassius auratus gibelio) after oral, intramuscular, intraperitoneal, and bath administration

The pharmacokinetics (PK) of cefquinome (CEQ) was studied in crucian carp (Carassius auratus gibelio) after single oral, intramuscular (i.m.), and intraperitoneal (i.p.) administration at a dose of 10 mg/kg body weight and following incubation in a 5 mg/L bath for 5 hr at 25°C. The plasma concentration of CEQ was determined using high-performance liquid chromatography (HPLC). PK parameters were calculated based on mean CEQ concentration using WinNonlin 6.1 software. The disposition of CEQ following oral, i.m., or i.p. administration was best described by a two-compartment open model with first-order absorption. After oral, i.m., and i.p. administration, the maximum plasma concentration (C_max ) values were 1.52, 40.53, and 67.87 μg/ml obtained at 0.25, 0.23, and 0.35 hr, respectively, while the elimination half-life (T_1/2β ) values were 4.68, 7.39, and 6.88 hr, respectively; the area under the concentration-time curve (AUC) values were 8.61, 339.11, and 495.06 μg hr/ml, respectively. No CEQ was detected in the plasma after bath incubation. Therapeutic blood concentrations of CEQ can be achieved in the crucian carp following i.m. and i.p. administration at a dosage of 10 mg/kg once every 2 days.

Pharmacokinetics of a single intramuscular injection of cefquinome in buffalo calves

The objective of this study was to investigate the pharmacokinetics of cefquinome following single intramuscular (IM) administration in six healthy male buffalo calves. Cefquinome was administered intramuscularly (2 mg/kg bodyweight) and blood samples were collected prior to drug administration and up to 24 hr after injection. No adverse effects or changes were observed after the IM injection of cefquinome. Plasma concentrations of cefquinome were determined by high-performance liquid chromatography. The disposition of plasma cefquinome is characterized by a mono-compartmental open model. The pharmacokinetic parameters after IM administration (mean ± SE) were C_max 6.93 ± 0.58 μg/ml, T_max 0.5 hr, t_½kα 0.16 ± 0.05 hr, t_½β 3.73 ± 0.10 hr, and AUC 28.40 ± 1.30 μg hr/ml after IM administration. A dosage regimen of 2 mg/kg bodyweight at 24-hr interval following IM injection of cefquinome would maintain the plasma levels required to be effective against the bacterial pathogens with MIC values ≤0.39 μg/ml. The suggested dosage regimen of cefquinome has to be validated in the disease models before recommending for clinical use in buffalo calves.

Preparation and evaluation of cefquinome-loaded gelatin microspheres and the pharmacokinetics in pigs

Cefquinome (CEF) is widely used for veterinary clinical applications because of its broad spectrum and high efficiency. However, frequent administrations are required due to its short elimination half-life. In this study, cefquinome sulfate gelatin microspheres (CEF-GMS) were prepared as a sustained-release formulation using emulsion chemical cross-linking technique. Physical properties, stability, sustained-release property in vitro, and pharmacokinetics in pigs were assessed. The morphology of CEF-GMS showed a good sphericity with porous structure on the surface, and the mean diameter was 8.80 ± 0.78 μm, with 90.60 ± 3.98% of the total in the range of 5-20 μm. There were no significant changes of all estimated indexes in the stability tests. In vitro drug release study showed that the release of CEF from CEF-GMS was much slower than that from crude CEF in a release medium. Pharmacokinetic characteristics were evaluated following intramuscular administration of CEF-GMS or Cefquinome sulfate injection (CEF-Inj) in pigs at a dosage of 4 mg CEF/kg body weight. The plasma drug concentration-time data of CEF-GMS and CEF-Inj were both best fitted by two-compartment models with first-order absorption, and the elimination half-life of CEF-GMS was almost 10 times that of CEF-Inj. Overall, CEF-GMS might be used as a sustained-release formulation of CEF for veterinary clinical applications.

Pharmacokinetics of cefquinome in tilapia (Oreochromis niloticus) after a single intramuscular or intraperitoneal administration

The pharmacokinetics of cefquinome was studied in plasma after a single dose (10 mg/kg) of intramuscular (i.m.) or intraperitoneal (i.p.) administration to tilapia (Oreochromis niloticus) in freshwater at 30 °C. Ten fish per sampling point were examined after treatment. The data were fitted to two-compartment open models following both routes of administration. The estimates of total body clearance (CL/F), volume of distribution (Vd/F), and absorption half-life (T1/2ka ) were 0.049 and 0.037 L/h/kg, 0.41 and 0.33 L/kg, and 0.028 and 0.035 h following i.m. and i.p. administration, respectively. After i.m. injection, the elimination half-life (T1⁄2β ) was calculated to be 5.81 h, the maximum plasma concentration (Cmax ) to be 49.40 μg/mL, the time to peak plasma cefquinome concentration (Tmax ) to be 0.14 h, and the area under the plasma concentration-time curve (AUC) to be 204.6 μg h/mL. Following i.p. administration, the corresponding estimates were 6.05 h, 44.39 μg/mL, 0.17 h and 267.8 μg h/mL. The minimum inhibitory concentrations of cefquinome, determined for 30 strains of Streptococcus agalactiae isolated from diseased tilapia, ranged from 0.015 to 0.12 μg/mL. Results from these studies support that 10 mg cefquinome/kg body weight daily could be expected to control tilapia bacterial pathogens inhibited in vitro by a minimal inhibitory concentration value of ≤2 μg/mL.

Pharmacokinetic profile of cefquinome after oral subchronic flubendiamide exposure and in vitro plasma protein binding in buffalo calves

The disposition kinetics study of cefquinome was conducted following single intravenous (IV) administration of 2mg/kg bodyweight in buffalo calves after oral subchronic exposure to flubendiamide and to determine the in vitro plasma protein binding of cefquinome. Plasma concentrations of cefquinome were analyzed using reverse-phase high performance liquid chromatography (HPLC). The results were compared with our earlier study on the pharmacokinetics of cefquinome in untreated buffalo calves. Plasma concentration-time data for cefquinome following IV injection were best fit into a two-compartmental open model in flubendiamide-exposed buffalo calves. Following flubendiamide exposure, most of the pharmacokinetic parameters of cefquinome were significantly altered in buffalo calves. Cefquinome was bound to plasma proteins of buffalo calves to the extent of 11.4±0.66%. In flubendiamide-exposed animals an intravenous dose of 2mg/kg body weight would maintain the therapeutic plasma levels required to be effective against the bacterial pathogens with MIC values ≤0.39μg/mL for only 12h, whereas in untreated buffalo calves the same dose of 2mg/kg body weight would maintain the plasma levels up to 24h, The study revealed that subchronic flubendiamide exposure significantly alters the disposition of cefquinome in buffalo calves.

Comparative Pharmacokinetics of Cefquinome (Cobactan 2.5%) following Repeated Intramuscular Administrations in Sheep and Goats

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.

Pharmacokinetic/pharmacodynamic relationship of cefquinome against Pasteurella multocida in a tissue-cage model in yellow cattle

The cephalosporin antimicrobial drug cefquinome was administered to yellow cattle intravenously (i.v.) and intramuscularly (i.m.) at a dose of 1 mg/kg of body weight in a two-period crossover study. The pharmacokinetic (PK) properties of cefquinome in serum, inflamed tissue-cage fluid (exudate), and noninflamed tissue-cage fluid (transudate) were studied using a tissue-cage model. The in vitro and ex vivo activities of cefquinome in serum, exudate, and transudate against a pathogenic strain of Pasteurella multocida (P. multocida) were determined. A concentration-independent antimicrobial activity of cefquinome was confirmed for levels lower than 4 × MIC. Integration of in vivo pharmacokinetic data with the in vitro MIC provided mean values for the time that drug levels remain above the MIC (T > MIC) in serum was 14.10 h after intravenous and 14.46 h after intramuscular dosing, indicating a likely high level of effectiveness in clinical infections caused by P. multocida of MIC 0.04 μg/mL or less. These data may be used as a rational basis for setting dosing schedules, which optimize clinical efficacy and minimize the opportunities for emergence of resistant organisms.

Pharmacokinetics following intravenous administration and pharmacodynamics of cefquinome in buffalo calves

Disposition following single intravenous injection (2 mg/kg) and pharmacodynamics of cefquinome were investigated in buffalo calves 6-8 months of age. Drug levels in plasma were estimated by high-performance liquid chromatography. The plasma concentration-time profile following intravenous administration was best described by a two-compartment open model. Rapid distribution of cefquinome was evident from the short distribution half-life (t ½ α = 0.36 ± 0.01 h), and small apparent volume of distribution (Vd area = 0.31 ± 0.008 L/kg) indicated limited drug distribution in buffalo calves. The values of area under plasma concentration-time curve, elimination half-life (t ½ β ), total body clearance (ClB), and mean residence time were 32.9 ± 0.56 μg · h/mL, 3.56 ± 0.05 h, 60.9 ± 1.09 mL/h/kg, and 4.24 ± 0.09 h, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration of cefquinome were 0.035-0.07 and 0.05-0.09 μg/mL, respectively. A single intravenous injection of 2 mg/kg may be effective to maintain the MIC up to 12 h in buffalo calves against the pathogens for which cefquinome is indicated.