Pharmacokinetics of an ampicillin/sulbactam (2:1) combination in rabbits

The pharmacokinetics of a 2:1 ampicillin-sulbactam combination in six rabbits, after intravenous and intramuscular injection at a single dosage of 20 mg/kg bodyweight (13.33 mg/kg of sodium ampicillin and 6.67 mg/kg of sodium sulbactam) were investigated by using a high performance liquid chromatographic method for determining plasma concentrations. The plasma concentration-time curves were analysed by compartmental pharmacokinetic and noncompartmental methods. The disposition curves for both drugs were best described by an open two-compartment model after intravenous administration and a one-compartment model with first order absorption after intramuscular administration. The apparent volumes of distribution calculated by the area method for ampicillin and sulbactam were 0.62 +/- 0.09 and 0.45 +/- 0.05 L/kg, respectively, and the total body clearances were 0.65 +/- 0.04 and 0.42 +/- 0.05 L/kg h, respectively. The elimination half-lives of ampicillin after intravenous and intramuscular administration were 0.64 +/- 0.11 and 0.63 +/- 0.16 h, respectively, whereas for sulbactam the half-lives were 0.74 +/- 0.12 and 0.77 +/- 0.17 h, respectively. The bioavailability after intramuscular injection was high and similar in both drugs (73.34 +/- 10.08% for ampicillin and 83.20 +/- 7.41% for sulbactam). The mean peak plasma concentrations of ampicillin and sulbactam were reached at similar times (0.20 +/- 0.09 and 0.34 +/- 0.15 h, respectively) and peak concentrations were also similar but nonproportional to the dose of both products administered (13.07 +/- 3.64 mg/L of ampicillin and 8.42 +/- 1.74 mg/L of sulbactam). Both drugs had similar pharmacokinetic behaviour after intramuscular administration in rabbits.

Milk kinetics of moxidectin and doramectin in goats

The milk kinetics of doramectin after a single subcutaneous administration and moxidectin following a single subcutaneous or oral drench were studied in goats (n = 15) at a dosage of 0.2 mg kg(-1). Doramectin could be detected in the milk for 21.0+/-2.9 days after subcutaneous treatment, and the total fraction of the dose recovered from the milk was estimated to be 2.9+/-0.88 per cent. Moxidectin, after either oral or subcutaneous administration, could be detected in the milk up to day 40 and the total fractions of the dose recovered from the milk were estimated to be 5.7+/-1.04 per cent and 22.53+/-1.09 per cent, respectively. The mean residence time after subcutaneous administration indicated that moxidectin delivered by the milk persists three times longer than doramectin; furthermore, the total fraction of the dose of moxidectin recovered from the milk was 7.7 times higher than that of doramectin.

Inflammatory breast carcinoma: pathological or clinical entity?

Inflammatory breast carcinoma (IBC) diagnosis is usually based in the presence of typical clinical symptoms (redness and edema in more than 2/3 of the breast), which are not always associated with pathologic characteristics (subdermal lymphatics involvement). Whether exclusively pathologic findings without clinical symptoms are sufficient for IBC diagnosis remains controversial. A retrospective analysis of 163 clinically diagnosed IBC (CIC) either with dermal lymphatics invasion or not, was compared with another group of 99 patients with dermal lymphatics invasion without clinical symptoms (occult inflammatory carcinoma) (OIC). The following clinical and pathological characteristics have been analyzed and compared: age, menopausal status, clinical axillar node involvement, symptoms duration before diagnosis, grade, estrogen receptors, presence of metastases at diagnosis, local recurrence, metastasic dissemination, disease-free (DFS) and overall survival (OS). Median age was younger in CIC (52.3 vs. 63.8 years; p < 0.001). Symptom duration before diagnosis were significantly shorter in CIC (3.4 vs. 6.8 months: p < 0.0001). Visceral (36.2% vs. 17.2%; p = 0.001) and brain metastases (7.4% vs. 1%; p = 0.02) was significantly more frequent in CIC. Negative estrogen receptors were more frequent in CIC (34.9% vs. 65.1%: p < 0.004). Five-years DFS (25.6 vs. 51.6%; p < 0.0001) and OS (28.6 vs. 40%; p < 0.05) were shorter in CIC. CIC (regardless of subdermal lymphatics involvement) must be clearly differentiated from OIC. Prognosis of CIC patients is poorer, so this two entities should be clearly differentiated when therepeutic results are reported.

Pharmacokinetics of amoxicillin/clavulanic acid combination after intravenous and intramuscular administration to pigeons

The pharmacokinetics of amoxicillin/clavulanic acid (4:1) combination were studied after intravenous and intramuscular administration of single doses (25 mg kg(-1) bodyweight) to 50 pigeons. The plasma concentrations-time data were analysed by compartmental pharmacokinetics and non-compartmental methods. The disposition curves for both drugs after intravenous administration were best described by a two-compartment open model. The apparent volumes of distribution of amoxicillin and clavulanic acid were 1.77 litres kg(-1) and 1.30 litres kg(-1) respectively. The body clearances of amoxicillin and clavulanic acid were not significantly different. The elimination half-lives of amoxicillin after intravenous and intramuscular administration were 1.22 (0.09) hour and 1.52 (0.09) hour respectively, and those of clavulanic acid were 1.15 (0.08) hour and 1.49 (0.08) hour. After intramuscular administration both drugs had a significantly longer half-life (P<0.05) than that after the intravenous treatment. The bioavailability after the intramuscular injection was high and similar for both drugs (75.98 per cent for amoxicillin and 74.61 per cent for clavulanic acid). The mean peak plasma concentration of clavulanic acid (0.29 hour) was reached earlier than amoxicillin (0.38 hour) and peak concentrations were proportional to the dose of both products administered (5.81 mg litre(-1) of amoxicillin and 1.89 mg litre(-1) of clavulanic acid). From a single administration it is proposed that an intramuscular dosage regimen of 105 mg kg(-1) of the combination (84 mg kg(-1) of amoxicillin and 21 mg kg(-1) of clavulanic acid) every 12 hours will achieve minimum concentrations > or =0.5 mg litre(-1) (minimum inhibitory concentration of most susceptible pathogens).

Some pharmacokinetic parameters of ampicillin/sulbactam combination after intravenous and intramuscular administration to goats

Some pharmacokinetic parameters of an ampicillin/sulbactam (2:1) combination were studied in six goats, after intravenous and intramuscular injection at a single dosage of 20 mg/kg bodyweight (13.33 mg/kg of sodium ampicillin and 6.67 mg/kg of sodium sulbactam). The drugs were distributed according to an open two-compartment model. The apparent volumes of distribution calculated by the area method of ampicillin and sulbactam were 0.34 +/- 0.04 l/kg and 0.45 +/- 0.15 l/kg, respectively, and the total body clearances were 0.72 +/- 0.11 and 0.38 +/- 0.07 l/kg.h. The half-lives of ampicillin after intravenous and intramuscular administration were 0.32 +/- 0.04 h and 0.71 +/- 0.14 h, respectively. For sulbactam the half-lives were 0.79 +/- 0.18 h and 1.13 +/- 0.21 h after administration by the same routes. The bioavailability after intramuscular injection was high and similar for both drugs (98.29% for ampicillin and 101.84% for sulbactam). The mean peak plasma levels of ampicillin (0.43 +/- 0.27 h) and sulbactam (0.34 +/- 0.14 h) were reached at a similar time, and peak concentrations were also similar and non-proportional to the dose of the products administered (11.02 +/- 3.11 mg/l of ampicillin and 9.5 +/- 0.98 mg/l of sulbactam).

Single-dose pharmacokinetics of ampicillin/sulbactam (2:1) combination after intravenous administration to sheep and goats

The pharmacokinetic behaviour of a combination of ampicillin and sulbactam (2:1) in six sheep and six goats after single intravenous doses of 20 mg kg body weight-1 (13.33 mg kg-1 of ampicillin and 6.67 mg kg-1 of sulbactam) was investigated by using a high-performance liquid chromatographic method for determining plasma concentrations. The objective was to determine whether there are differences between sheep and goats in the disposition kinetics of ampicillin and sulbactam. The plasma concentration-time curves were analysed by compartmental pharmacokinetic and non-compartmental methods. The disposition curves for both drugs were best described by a biexponential equation (two-compartment open model) in both sheep and goats. The mean (SD) elimination half-lives of ampicillin were 0.32 (0.05) h in sheep and 0.32 (0.04) h in goats, and the half-lives of sulbactam were 0.74 (0.10) h and 0.79 (0.18) h in sheep and goats, respectively. The apparent volumes of distribution of ampicillin and sulbactam were similar in the two species. Mean (SD) body clearances of ampicillin were 0.69 (0.07) litre h-1 kg-1 in sheep and 0.72 (0.11) litre h-1 kg-1 in goats, and the body clearances of sulbactam were 0.38 (0.03) and 0.38 (0.07) litre h-1 kg-1 in sheep and goats, respectively. There were no significant differences between any of the pharmacokinetic parameters of ampicillin and sulbactam in the sheep and goats.

Pharmacokinetics of amoxicillin/clavulanic acid combination after intravenous and oral administration in goats

The intravenous and oral pharmacokinetics of an amoxicillin and clavulanic acid combination (20 mg/kg of sodium amoxicillin and 5 mg/kg of potassium clavulanate) were studied in six goats. After intravenous administration the pharmacokinetics of both drugs could be described by an open two-compartment model. Amoxicillin had a greater distribution volume (0.19 +/- 0.01 l/kg) than clavulanic acid (0.15 +/- 0.01 l/kg), whereas the distribution and elimination constants were higher for the latter, which was eliminated more quickly than amoxicillin. After oral administration of both drugs their pharmacokinetic behaviour was best described by an open one-compartment model with first-order absorption. Elimination half-lives were twice as long after oral (2.15 +/- 0.20 h and 1.94 +/- 0.16 h for amoxicillin and clavulanic acid respectively) than after intravenous administration (1.20 +/- 0.16 h and 0.86 +/- 0.09, respectively). An apparent 'flip-flop' situation was evident in this study. Bioavailability was 27% for amoxicillin and 50% for clavulanic acid.