Pharmacodynamics and pharmacokinetics of cefoperazone and cefamandole in dogs following single dose intravenous and intramuscular administration

Plasma disposition of cefoperazone after single intravenous and intramuscular administrations in camels (Camelus dromedarius)

The plasma disposition of cefoperazone was investigated after intravenous (IV) and intramuscular (IM) administrations of 20 mg/kg as a single dose in six camels (Camelus dromedarius) in a crossover design. Blood plasma samples were analysed by high-performance liquid chromatography (HPLC). After IV administration, elimination half-life (t_1/2β), volume of distribution at steady state (V_dss), total body clearance (Cl_tot) and mean residence time (MRT) of cefoperazone were 1.95 h, 0.38 L/kg, 0.17 L/h/kg and 2.16 h, respectively. After IM administration of cefoperazone, peak plasma concentration (C_max) was 21.95 μg/mL and it was obtained at (t_max) 1.23 h. Absorption half-life (t_1/2ab), elimination half-life and mean absorption time were 0.45 h, 2.84 h and 2.07 h, respectively. The bioavailability of cefoperazone was 89.42%. The lack of local reaction or any other adverse effects and the very good bioavailability following IM administration indicate that cefoperazone might be a promising alternative treatment for a variety of infectious diseases in camels.

Pharmacokinetics and pharmacodynamics of oral and intravenous cefetamet in dog

The pharmacokinetic (PK) and pharmacodynamic (PD) properties of intravenously (IV) administered cefetamet-Na and per os (PO) administered cefetamet pivoxil were investigated in eighteen healthy dogs at three different dose levels. The three doses for IV cefetamet-Na were 95, 190 and 380 mg, while those for oral cefetamet pivoxil were 125, 250 and 500 mg (both equivalent to 90, 180 and 360 mg of cefetamet). An efficacy predictor, measured as the ratios of the time that the concentration of the free drug is over the MIC90 (T > MIC90) and the dosing interval (f% T > MIC90) of IV and PO administration were calculated. The PK parameters' maximum concentration (C max), half-life (t 1/2) and area under the curve (AUC0-t ) after three IV doses were 42.85 ± 11.79 μg/mL, 1.66 ± 0.36 h and 80.10 ± 28.92 mg h/L (95 mg); 93.50 ± 30.51 μg/mL, 1.47 ± 0.13 h and 1.47 ± 0.13 mg h/L (190 mg); 185.74 ± 113.83 μg/mL, 1.60 ± 0.38 h and 263.20 ± 73.27 mg h/L (380 mg). After PO administration, the C max, t 1/2 and AUC0-t at three doses were 9.25 ± 1.02 μg/mL, 1.79 ± 0.50 h and 31.90 ± 4.76 mg h/L (125 mg); 9.75 ± 1.77 μg/mL, 1.93 ± 0.65 h and 42.69 ± 8.93 mg h/L (250 mg); 15.55 ± 6.65 μg/mL, 2.02 ± 0.54 h, and 68.72 ± 24.11 mg h/L (500 mg). The IV f% T > MIC90 was greater than PO f% T > MIC90 when MIC90 was within the range of 0.25-256 mg/L.

Correlation between in silico physicochemical characteristics of drugs and their mean residence time in human and dog

The correlation between 52 physicochemical parameters and mean residence time (MRT) for 27 drugs used in human and dog were investigated. The physicochemical parameter values calculated provided a basis for deriving a series of arithmetic expressions, which were used to build a mathematical model describing the relationship between them and the MRT values. From the entire set of analyzed parameters, a subset of 14 was identified that contributed to the derivation of an arithmetic expression: Log(PSA - WPSA + ACID) x [XlogP - (LogKp - EAxLn(Caco2 + AMINE + SAF))] + (AMIDE + IP - FG) - Ln(MW + PISA) the value of which is highly correlated with the MRT value in dogs (P < .001) and allowed prediction of the MRT predicted (MRT(pred)). In humans, no correlation was found that allowed the calculation of MRT(pred). These results indicate that predicting the pharmacokinetics of any specific drug for humans based on pharmacokinetic data obtained in the dog should be undertaken with knowledge of the inherent limitations.