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Biomedical subjects

R Wise

Publications and source records attributed to R Wise.

At least 433 records · Page 24Linked to original sources
PubMed1981

Cefoperazone and cefotiam--two new cephalosporins: an in-vitro comparison.

The in vitro activity of cefoperazone (CPZ) and cefotiam (CTM) was compared to other available cephalosporins. Using an agar dilution procedure both CTM and CPZ were more active against the Enterobacteriaceae tested than cefoxitin, cefuroxime and cefazolin; CTM being slightly more active than CPZ, in particular against Klebsiella spp Haemophilus influenzae were more susceptible to CPZ. CTM had no activity against Pseudomonas aeruginosa but CPZ exhibited considerable activity (mode MIC 4 mg/l). Against Bacteroides fragilis CPZ had a similar activity to cefuroxime, but CTM was less active. CTM was about twice as active as CPZ against Staphylococcus aureus, cefazolin being the most active agent tested. The MBC was about twice the MIC for each compound and the presence of 75% serum had only a modest effect on the MIC and MBC. The protein binding of CPZ was 94% and CTM 62%.

Ampicillin↗
PubMed1981

Pharmacology of cefotaxime and its desacetyl metabolite in renal and hepatic disease.

The pharmacology of cefotaxime and the metabolite desacetyl cefotaxime was studied in 40 patients with various degrees of renal and hepatic failure who received 0.5 or 1 g of cefotaxime intravenously. Patients with severe renal impairment (creatinine clearance, 3 to 10 ml/min) had a cefotaxime serum half-life of 2.6 h and desacetyl cefotaxime serum half-life of 10.0 h. The equivalent figures were 1.0 and 1.5 h, respectively, in subjects with normal renal function. The presence of an acute coexisting illness together with severe renal impairment was associated with a further prolongation of the serum half-lives. Hepatic dysfunction was accompanied by a reduction in desacetyl metabolite formation. A reduction of cefotaxime dosing to 0.5 g twice a day would appear prudent when the creatinine clearance is 5 ml/min or less to avoid accumulation of the parent compound and the metabolite.

Cefotaxime↗
PubMed1981

Epimers of moxalactam: in vitro comparison of activity and stability.

Moxalactam exists in two epimeric forms, R and S. The in vitro activity of these two epimers was compared with that of material available for clinical and laboratory use (R + S moxalactam). Generally, R moxalactam was twice as active as the S form. The stability of R + S moxalactam was studied at 37, 20, 4 and -20 degrees C in buffer and serum. Only in serum at 37 degrees C was there any appreciable loss of activity (half-life, 8 h). The stability of R and S epimers was studied separately, and the composition of the resulting equilibrium was investigated. At 37 degrees C in serum, one-half of the excess of either R or S over the equilibrium mixture was converted into the equilibrium mixture in 1.5 h. The proportions of R to S in an equilibrium mixture in buffer were 50:50, but in serum they were 45:55. It is doubtful whether these differences in stability and activity will have any significant clinical importance.

Anti-Bacterial Agents↗
PubMed1981

Comparison of ceftazidime and cefamandole pharmacokinetics and blister fluid concentrations.

Eight healthy male volunteers received 1 g of either ceftazidime or cefamandole as an intravenous infection. Serial blood samples were taken over the next 8 h. Urine samples were collected over 24 h. Levels of these antibiotics were measured in the fluid of blisters resulting from application of cantharides. The concentration of ceftazidime in serum at 0.25 h after intravenous injection was 83.3 micrograms/ml. The serum half-lives for the respective drugs were 1.8 and 0.8 h. The mean apparent volume of distribution of ceftazidime (13.6 liters) was greater than that of cefamandole (9.8 liters). Plasma clearance was 111 ml/min for ceftazidime and 216 ml/min for cefamandole. The maximum blister fluid concentration of ceftazidime was 45.9 micrograms/ml, and that of cefamandole was 22.1 micrograms/ml. The relative availability of each drug in blister fluid compared with serum was similar.

Adult↗
PubMed1981

Comparative multiple-dose pharmacokinetics of cefotaxime, moxalactam, and ceftazidime.

The pharmacokinetics of cefotaxime, moxalactam, and ceftazidime were investigated in six human volunteers who received in a crossover fashion doses of 0.5, 1.0, and 2.0 g of each drug by a 5-min infusion. Doses of 1.0 g were repeated after the administration of probenecid. Serum and urine concentrations were assayed with an agar diffusion method. Serum concentrations of moxalactam exceeded those of ceftazidime at all times and were distinctly higher than those of cefotaxime. The normalized area under the concentration time curve (defined as the ratio of the area under the curve per dose) reflects this relationship: compared with cefotaxime the normalized area under the curve of moxalactam was 3 to 4 times higher, and that of ceftazidime was 2 to 3 times higher. By intra-individual comparisons, the area under the curve of moxalactam was 44% larger than that of ceftazidime. With increasing doses, cefotaxime exhibited a nonlinear increase of the area under the curve. The half-lives of moxalactam, ceftazidime, and cefotaxime were 2.34, 1.95, and 1.16 h, respectively. The volume of distribution averaged 0.20 +/- 0.03, 0.23 +/- 0.02, and 0.25 +/- 0.04 liters per kg, and the mean total body clearance was 84, 131, and 328 ml/min for moxalactam, ceftazidime, and cefotaxime, respectively. The 24-h urinary recovery was highest for moxalactam (75 +/- 4%) followed by ceftazidime (68 +/- 11%) and cefotaxime (53 +/- 6%). The influence of probenecid on serum concentrations, half-life, area under the curve, and clearance was most apparent with cefotaxime, whereas the pharmacokinetics of moxalactam and ceftazidime were only slightly affected. After the 0.5- and 2.0- g doses of cefotaxime, desacetyl-cefotaxime activity (determined by high-pressure liquid chromatography) reached a peak of 2.7 and 9.9 mug/ml and declined with a half-life of 1.9 and 1.4 h. The ratio of the R(-) and S(-) epimers of moxalactam, which could be differentiated by high-pressure liquid chromatography, fell rapidly from 0.81 at 0.17 h to 0.5 at 5 h, indicating the presence of twice as much of the microbiologically less active S(-) epimer. From a pharmacokinetic standpoint it appears reasonable to conclude that moxalactam and possibly ceftazidime could be administered twice daily and that cefotaxime could be administered three or even four times daily.

Cefotaxime↗