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Biomedical subjects

P Koeppe

Publications and source records attributed to P Koeppe.

At least 19 recordsLinked to original sources
PubMed1992

Pharmacokinetics of loracarbef and interaction with acetylcysteine.

A study was conducted to evaluate the pharmacokinetics of loracarbef, a new synthetic oral carbacephem antibiotic, following administration of 400 mg in normal male volunteers. The influence of food and possible interaction with acetylcysteine, a commonly used mucolytic agent, was also studied. Twelve healthy volunteers participated in the study and randomly received an oral dose of 400 mg loracarbef in the fasting state, 400 mg loracarbef following a standard breakfast or 400 mg loracarbef together with 200 mg acetylcysteine in granular form. Serum and urine concentrations were determined over 24 h by means of a bioassay. Loracarbef was well tolerated. Four volunteers complained of mild, transient headache. The substance was well absorbed with a mean peak level of 19.21 +/- 3.94 mg/l in the fasting state; it was primarily excreted in active form via the kidneys (urine recovery/24 h: 86-92%). The elimination half-life ranged from 70.3 to 102.0 min. Acetylcysteine had no effect on the absorption of loracarbef. The intake together with food delayed the absorption time, but had no influence on the bioavailability.

Acetylcysteine↗
PubMed1992

Pharmacokinetics of roxithromycin and influence of H2-blockers and antacids on gastrointestinal absorption.

The pharmacokinetics of roxithromycin (300 mg orally) and the influence of the antacid aluminum magnesium hydroxide and the H2-blocker ranitidine on bioavailability of roxithromycin in ten healthy volunteers were studied. Pharmacokinetics after a single dose of roxithromycin were characterized by high peak serum levels (9.1 +/- 2.1 mg/l) and a long elimination half-life (7.2 +/- 2.5 h), resulting in a large area under the curve (116.9 +/- 32.7 mg h/l). High inter- and intraindividual variations were found for both the absorption time and the elimination half-life. The bioavailability of roxithromycin was not affected by coadministration with antacids or ranitidine.

Adult↗
PubMed1992

Multiple dose pharmacokinetics, safety, and effects on faecal microflora, of cefepime in healthy volunteers.

In a randomized, double-blind, placebo-controlled study in 12 healthy volunteers pharmacokinetics, safety and impact on the faecal microflora of cefepime were determined. For eight days eight volunteers received cefepime 1000 mg bd by constant infusion over 30 min, four volunteers received placebo. Concentrations of cefepime in serum and urine were measured by bioassay and HPLC. The correlation between the two methods was good and the bioassay results were used for pharmacokinetic calculations. The faecal flora was analysed twice before the study, twice during the study and four times after cefepime administration. There were no significant differences in the pharmacokinetic parameters between days 1 and 8. The following values (mean +/- S.D.) represent day 1. The maximum concentration of 72.69 +/- 12.2 mg/L immediately after infusion decreased to 0.56 +/- 0.17 mg/L after 12 h. The mean 12 h recovery in urine was 93.69 +/- 2.14%. Pharmacokinetic parameters based on an open two-compartment model were as follows (mean +/- S.D.): area under the curve, 142.65 +/- 18.35 mg.h/L; elimination half-life 110.3 +/- 8.3 min; steady state volume of distribution 16.0 +/- 1.9 L/70 kg; total clearance, 107.0 +/- 16.0 mL/min; renal clearance 103.0 +/- 15.2 mL/min. No accumulation was observed during the eight day study period with cefepime at this dosage; trough levels on days 2-7 ranged from 0.52 +/- 0.26 mg/L to 0.90 +/- 0.33 mg/L. In the cefepime treated group the following side-effects were noted: headache (5), fatigue (4), nausea/stomach ache (2), soft stool (2), transient scotoma (1). Side-effects in the placebo group were: headache (2) fatigue (3), nausea/stomach-ache (1), soft stool (2) and photophobia (1). During cefepime administration a decrease in the number of Escherichia coli and bifidobacteria in faeces was observed, whereas Bacteroides spp. and clostridia showed a slight increase. The numbers of faecal bacteria returned to normal 20 to 48 days after the study was completed.

Bacteroides↗
PubMed1992

Multiple-dose pharmacokinetics of cefprozil and its impact on intestinal flora of volunteers.

The pharmacokinetics of cefprozil were determined with 12 volunteers (8 received cefprozil and 4 received a placebo) after oral administration of 500 mg every 12 h over an 8-day period in a randomized, double-blind, placebo-controlled design. Concentrations in serum and urine were measured by high-pressure liquid chromatography and bioassay. The pharmacokinetic parameters were calculated on the basis of an open one-compartment model. The mean maximum concentration in serum on day 1 was 11.5 +/- 2.6 mg/liter, and the time to reach maximum concentration was 122.3 +/- 30 min after administration. Bioavailability parameters (area under the concentration-time curve from zero to infinity, maximum concentration of the drug in serum, and urinary recovery) indicated an excellent absorption. No accumulation over the 8-day period was registered. Cefprozil had a short biological elimination half-life of 58 +/- 10 min and a renal clearance of 210 +/- 51 ml/min, indicating high rates of renal excretion and tubular secretion. Analysis of the fecal flora showed an ecological impact of cefprozil on the intestinal microflora, such as a moderate decrease in enterobacteria and a slight increase in enterococci, staphylococci, and bacteroides during the study. The number of all bacterial species was already normalized 4 days after the administration period. The tolerance of cefprozil proved to be excellent; only a slight and reversible increase of liver enzymes (in two volunteers), mild cephalalgia, tiredness, and soft stool were registered during the 8-day period. Cefprozil had excellent absorption, no accumulation over an 8-day period, and only a limited impact on the intestinal microflora.

Administration, Oral↗
PubMed1992

Pharmacokinetics of cefpodoxime proxetil and interactions with an antacid and an H2 receptor antagonist.

Cefpodoxime proxetil is a new oral esterified cephem antibiotic with a broad antibacterial spectrum. The dissolution of cefpodoxime proxetil is pH dependent. The objectives of this study were to characterize the pharmacokinetics of cefpodoxime proxetil in two different oral doses and to examine possible interactions with an antacid, aluminum magnesium hydroxide (Maalox 70), and an H2 receptor antagonist, famotidine. Two studies involving the same 10 healthy volunteers were performed. In the first study, cefpodoxime proxetil was administered in two doses, 0.1 and 0.2 g. In the second study, two interventions were performed in a randomized crossover design. For one intervention, the volunteers were pretreated with 40 mg of famotidine 1 h before 0.2 g of cefpodoxime proxetil was administered. In the second trial, participants were given 10 ml of Maalox 70 2 h and 10 ml of Maalox 70 15 min before they received 0.2 g of cefpodoxime proxetil. Serum and urine concentrations were determined by high-performance liquid chromatography. For the statistical evaluation, these data were tested by using the pharmacokinetics of 0.2 g of cefpodoxime proxetil from the first study. The maximum concentrations were 1.19 +/- 0.32 mg/liter after 0.1 g of cefpodoxime proxetil and 2.54 +/- 0.64 mg/liter after 0.2 g of cefpodoxime proxetil. The elimination half-lives were 149 min for 0.1 g and 172 min for 0.2 g of cefpodoxime proxetil. The total increase in the area under the concentration-time curve (AUC) was dose dependent. Combination with Maalox 70 caused a reduction in the AUC from 14.0 +/- 3.9 to 8.44 +/- 1.85 mg.h/liter. After famotidine, the AUC decreased to 8.36 +/- 2.0 mg . h/liter. Corresponding changes were registered for the maximum concentration of drug in serum, 24-h urine recovery, and the time to maximum concentration of drug serum. Cefpodoxime proxetil was well tolerated without any seriously adverse drug reactions.

Administration, Oral↗
PubMed1979

Comparative pharmacokinetics of cephalexin, cefaclor, cefadroxil, and CGP 9000.

In a randomized crossover study, the pharmacokinetics of three new cephalosporin antibiotics, cefaclor, cefadroxil, and CGP 9000, in comparison to cephalexin, were determined after oral administration, by capsules, of 1,000 mg on an empty stomach in 12 normal subjects. Serum concentrations were measured during a period of 8 h, and urine recovery was measured during 24 h. The significant parameters of bioavailability of an orally administered substance were determined. The maximal serum concentrations (y(max)) for cephalexin, cefaclor, cefadroxil, and CGP 9000 (in milligrams per liter) were: 38.8 +/- 8.1; 34.6 +/- 7.8; 33.0 +/- 5.4; and 23.3 +/- 7.3, respectively. The areas under the curve (in hours x milligrams per liter) were: 93.0 +/- 14.8; 74.5 +/- 9.9; 70.1 +/- 9.0; and 108.5 +/- 18.4, respectively. In a further crossover study with six subjects, 1,000 mg of cephalexin and of cefadroxil were given during a standard breakfast. The y(max) of cephalexin decreased to 23.1 +/- 6.6 mg/liter, in contrast to cefadroxil, with an unchanged y(max) of 32.7 +/- 3.4 mg/liter.

Administration, Oral↗
PubMed1978

[Pharmacokinetics of ticarcillin in patients with normal and impaired renal function (author's transl)].

Elimination half-life of ticarcillin was measured in 61 patients with different levels of renal function after intravenous rapid infusion (1--20 g). Assuming a single-compartment model for elimination, there was in those without renal disease a half-life of approximately 71 minutes, although there were considerable individual variations. In patients with impaired renal function (glomerular filtration rate 30--60 ml/min) the values were between 60 and 120 minutes, while in one patient with a filtration rate of 2.08 ml/min it was over 400 min. If there is a correlation between dose and half-life, it was obscured by the individual variations. Distribution volume was 21 1/100 kg body-weight.

Bacterial Infections↗
PubMed1978

Measurement of lung density by computed tomography.

Computed tomography scanners can be calibrated to provide reproducible measurements for a quantitative analysis of lung density. Typical histograms for inspiration and expiration are presented. The reproducibility of the method is demonstrated as well as the limitations caused by artifacts and incomplete inspiration. This method is suggested for follow-up studies of patients with diseases affecting the entire lung. Early detection of interstitial lung disorders also seems possible.

Absorptiometry, Photon↗
PubMed1978

[Comparative experimental studies in animals and humans on gastrointestinal blood loss following antirheumatic pharmacotherapy (author's transl)].

The gastrointestinal blood loss caused by the two antirheumatic drugs acetyl salicylic acid (ASA) and 4-acetamidophenyl-2-acetoxybenzoate (benorilate, Benortan) was compared in experimental animals and humans by measuring the total body iron retention. In Wistar rats and humans the results indicate that the daily iron loss under ASA is significantly higher (almost by the factor 2) than that under benorilate.

Animals↗
PubMed1978

[On the description of the compton-effect (author's transl)].

The short paper presents a comparative description of the Compton-, Photo-, and Pair Creation Effect, respectively, for Non-Physicists. The cause for this note is the fact that the Compton Effect is nearly always incorrectly described in (German) "Introductions in Radiation Protection" and similar semi-popular publications.

Nuclear Physics↗
PubMed1978

[Pharmacologic studies or aminoglycoside antibiotics (amikacin, gentamicin, sisomicin, tobramycin)].

In a randomized study of 12 healthy subjects, the pharmacokinetics of gentamicin, sisomicin and tobramycin were determined after a one-hour infusion of each drug (1.0 mg/kg body-weight). There were no pharmacokinetic differences of therapeutic significance between the three drugs. The mean serum concentrations at the end of infusion were 3.85 microgram/ml for gentamicin and 4.66 microgram/ml for sisomicin, falling to 0.12 and 0.26 microgram/ml, respectively, after eight hours. The biological half-life varied between 96 and 122 min and the apparent volumes of distribution corresponded closely to the size of the extracellular space.--The pharmacokinetic data of amikacin were determined after a one-hour constant infusion, the mean amikacin serum concentration was 37.5 microgram/ml and, 8 hours later, decreased to an average of 1.3 microgram/ml. The biological half-life amounted to a mean of 114.2 +/- 16.7 min, and the apparent volume of distribution could be calculated with 18.1 +/- 1.81/100 kg body weight.

Adult↗
PubMed1977

[Whole body computer tomography: principle-purpose - requirements (author's transl)].

After explaining the principle of whole body computer tomography the field of indication is outlined with reference to some of our own experiences. Up to now, it has proved its value in the following indications: preoperative diagnosis, supplementing pulmonary radiodiagnosis, substitution of invasive diagnostic procedures in mediastinal diseases, clarification of diseases of the abdominal cavity, of space-occupying processes in the kidney, in the true pelvis, and detection of retroperitoneal processes. The financial expenditure for this novel method of investigation is described according to a formula. The cost of given or estimated numerical values show the importance of adequate usage. The added costs for a second personnel shift for an examination rate of more than 7 patients a day are trivial because of the high basic expenditure.

Abdominal Neoplasms↗
PubMed1977

[Azlocillin and mezlocillin: two new semisynthetic acylureido-penicillins (author's transl)].

The pharmacokinetic parameters of two new ureido-penicillins (azlocillin and mezlocillin) were determined in 12 healthy subjects after a half-hour continuous infusion of 5,000 mg. The agar diffusion test (test strain Bacillus subtilis ATCC 6633) was used for the microbiological assays. The mean azlocillin serum concentration after the half-hour infusion was 431.0 +/- 75.0 microgram/ml; after eight hours it had fallen to a mean value of 4.7 +/- 2.6 microngram/ml. The mean elimination half-life was 77.5 +/- 10.4 minutes, and the relative distribution volume was 19.4 +/- 1.9% of the bodyweight. At the end of the infusion, mezlocillin showed a mean serum concentration of 426.0 +/- 61.0 microgram/ml and after eight hours an average of 1.1 +/-0.9 microgram/ml; the half-life was shorter (56.9 +/- 9.9 minutes) and the distribution volume lower (14.8 +/- 3.1%) than that of azlocillin. The renal clearance values measured in three subjects during a four-hour continuous infusion were: azlocillin 111.6 ml/min/1.73 m2, mezlocillin 121.5 ml/min/1.73 m2. The kinetic behaviour of the two ureido-penicillins was essentially very similar to that of ampicillin and carbenicillin, 38 patients with bronchopneumonia, cholangitis or urinary tract infections, which in some instances were severe, were treated for an average of 10 days with an average daily dosage of 3X4.0 g azlocillin or 3X5.0 g mezlocillin. 30 patients showed clinical improvement, and in 17 of these the pathogen was eliminated. These therapeutic results appear more favourable than those obtained with the newer aminoglycoside antibiotics (amikacin, sisomicin); in particular the drug was well tolerated.

Adult↗
PubMed1977

[Clinical-radiological evaluation of barium sulfate suspension in double contrast examination (author's transl)].

In four selected, commercial barium sulfate preparations, viscosity, surface tension and particle size were measured; examined were agglomeration, sedimentation and homogeneity in vitro. For the clinical-radiological examination, an evaluation scheme has been developed containing the following criteria: uniformity and thickness of contrast medium layer, demonstration of the areae gastricae, clearness of gastric contour, and vesiculation. A blind study, encompassing about 100 double contrast examinations of each preparation, ascertained the usability of this scheme. Significant differences could be detected among the four contrast media. The barium sulfate suspension which was rated the highest lay within a viscosity range of 50-90 cP, had a particle diameter of 0.2-1.6 micrometer and showed the least degree of agglomeration. Results of the in vitro examinations, when compared to the clinical tests, lead to the conclusion that both, gastric mucous and contrast medium additives, may exert considerable influence on the pictorial quality of the above defined criteria.

Barium Sulfate↗