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Biomedical subjects

T Bergan

Publications and source records attributed to T Bergan.

At least 217 records · Page 12Linked to original sources
PubMed1978

Pharmacokinetics of bacampicillin compared with those of ampicillin, pivampicillin, and amoxycillin.

Bacampicillin, a new oral prodrug which in vivo is rapidly transformed to ampicillin, was compared with ampicillin, pivampicillin, and amoxycillin in a randomized cross-over study on 11 healthy volunteers. All drugs were given in oral doses equimolar to 400 mg of bacampicillin (800 mumol). The mean of the individual peak concentrations in serum was 8.3 mug/ml for bacampicillin, 7.1 mug/ml for pivampicillin, 7.7 mug/ml for amoxycillin, and 3.7 mug/ml for ampicillin. Furthermore, bacampicillin had a higher absorption rate than all the other drugs, although there were statistically significant differences only versus ampicillin. The peak serum levels of the individual subjects were more dispersed with ampicillin and amoxycillin, suggesting a more uniform absorption of bacampicillin and pivampicillin. The relative bioavailability of bacampicillin and pivampicillin was comparable, whereas ampicillin was only 2/3 that of the others.

Amoxicillin↗
PubMed1978

Pharmacokinetic comparison of oral bacampicillin and parenteral ampicillin.

Bacampicillin is a new oral prodrug which is rapidly converted to ampicillin during absorption from the gastrointestinal tract. High serum peaks of ampicillin are obtained. Bacampicillin orally was compared pharmacokinetically with parenteral ampicillin (intravenously and intramuscularly). A cross-over study on healthy volunteers showed that ampicillin concentrations after equimolar doses of bacampicillin orally and ampicillin intramuscularly were of the same order. The mean of the individual peak values (regardless of time of occurrence) after a dose of 800 mg of bacampicillin was 13.1 +/- 3.8 mug/ml. Absorption rates of the two doses were similar, as were their distribution volumes (approximately 25% of the body weight). Bioavailability was 87% for bacampicillin, compared to 71% for ampicillin.

Absorption↗
PubMed1978

Pharmacokinetics of mezlocillin in healthy volunteers.

Mezlocillin in doses of 1.0, 2.0, and 5.0 g and carbenicillin in doses of 2.0 g were given as bolus injections intravenously to 10 healthy volunteers. For mezlocillin, dose-dependent pharmacokinetics was detected. This is reflected by a more than proportional rise in serum concentrations and a decreased total body clearance as doses were increased. Per dose unit, the areas under serum concentration curves to infinity were 33.5 mug.h/ml for the 1.0-g dose, 47.2 mug.h/ml for the 2.0-g dose, and 54.8 mug.h/ml for the 5.0-g dose. The body clearance fell from 31.2 liters/h with the 1.0-g dose to 17.0 liters/h with the 5.0-g dose. This can be explained mainly by a marked depression of nonrenal clearance, which fell from 12.2 to 3.8 liters/h, compared with a parallel change in renal clearance from 19.0 to 13.2 liters/h. Contributing to the non-linearity may be biotransformation, evacuation via bile, or another process. With dose increments, rising amounts are recovered unchanged in the urine-61% after a 1.0-g dose compared with 69% after a 5.0-g dose. This clearly defines metabolism as a major factor of elimination. Carbenicillin, for which the first-order, two-compartment open model was applicable here as in previous studies, had a longer serum half-life than did mezlocillin. For the 2.0-g doses, the former had a half-life of 1.4 h, compared with 0.8 h for the latter (calculated as if the two-compartment model were fully valid). The relative area under the curve (see above) was 76.1 mug.h/ml after the 2.0-g dose.

Adult↗
PubMed1978

Absorption, distribution and elimination of cefazolin in patients with normal renal function.

Cefazolin was given intramuscularly in a dosage of 1.0 g to 13 bed-ridden patients during treatment for various infections, and the pharmacokinetics evaluated in each subject. In 9 patients the mean serum half-life was 2.7 h, whereas in 4 patients--all over 60 years of age--it was significantly above this value. Impaired renal fuction could not explain the prolonged excretion time in the last group.

Absorption↗
PubMed1978

Penicillins.

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Animals↗
PubMed1978

The mini-pig as a model for penetration of penicillins.

To be active, antimicrobials must reach the bacteria in the infectious foci in adequate concentrations. Direct measurements of levels in the various foci are difficult to perform, but a number of animal models with artificial extravascular foci have been developed. In many ways, the physiology of pigs resemble that of humans. Consequently, it was thought that pigs might also parallel humans in the handling of penicillins. General pharmacokinetics of ampicillin and flucloxacillin and the penetration of the substances to subcutaneously implanted teflon tistisue chambers were investigated. Ampicillin was given intramuscularly, orally, and as the pro-drug bacampicillin.

Ampicillin↗
PubMed1978

A medical education program strategy for community hospitals.

Community hospital physicians, nurses, and other health care practitioners should be involved in their institution's educational planning activities. Strategic planning that considers both internal and external pressures is required. All programs should have clear, measurable goals; be flexible; and subjected to continuous reassessment. All efforts must be related to quality of patient care as judged by community standards.

Education, Medical↗
PubMed1978

Kinetics of tissue penetration. Are high plasma peak concentrations or sustained levels preferable for effective antibiotic therapy?

The experimental evidence and the theory of antibiotic transport into peripheral foci of infection have been discussed. Support is presented in favour of the concept that intermittent dosage with peak concentrations of sufficient size would seem preferable. The duration of plasma concentrations above certain thresholds is a basic requirement for successful antimicrobial therapy.

Anti-Bacterial Agents↗
PubMed1977

Kinetics of a sulfadiazine-trimethoprim combination.

The pharmacokinetics of a combination of sulfadiazine and trimethoprim has been studied in 16 patients with varying degrees of reduced renal function. In normal renal function, the serum half-life (t1/2) of active sulfadiazine, total sulfadiazine, and trimethoprim were quite close: 7.7, 9.6, and 12.1 hr, respectively. There was a gradual increase in serum t1/2 with reduction in renal function for both active and total sulfadiazine and for trimethoprim. With accurate determinations of endogenous renal clearance, t1/2 estimates may be made from regression curves presented. The relative distribution in the body was unrelated to renal function. It was similar for the two fractions of sulfonamide and higher for trimethoprim. The means were 0.371, 0.176, and 1.104 L/kg, respectively, for active and total sulfadiazine, and trimethoprim.

Absorption↗
PubMed1976

Displacement of albumin-bound antimicrobial agents by bilirubin.

The ability of bilirubin to displace antimicrobial agents from their binding sites on albumin was studied in vitro by equilibrium dialysis. Sulfonamides, tetracyclines, penicillins and cephalosporins of different degrees of protein binding were tested. It was found that bilirubin reduced the protein binding of all four classes of antimicrobial agents, although by varying degrees. This effect was most pronounced with the compounds which had the highest degree of protein binding, such as cloxacillin, cephazolin, methacycline and sulfisoxazole, all of which are bound greater than 80% by albumin. On the other hand, the drugs with less than 25% binding, such as ampicillin, cephalexine and tetracycline were not ostensibly displaced by bilirubin. Scatchard plots of the binding of sulfamethoxazole to albumin in the presence of 400 mumol/1 of bilirubin, showed that bilirubin almost completely displaced the sulfonamide molecule from the high affinity site on the albumin molecule. Reduced protein binding of drugs in hyperbilirubinemic infants may have pharmacokinetic significance.

Anti-Infective Agents↗