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Biomedical subjects

G Humbert

Publications and source records attributed to G Humbert.

At least 127 records · Page 7Linked to original sources

Pharmacokinetics of moxalactam in subjects with normal and impaired renal function.

The pharmacokinetics of moxalactam were investigated in five subjects with normal renal function and 21 uremic patients. Normal subjects were given intravenous doses of 7.5 and 15 mg of the drug per kg as bolus injections (1 min) and 30 mg of the drug per kg as a 20-min infusion. Pharmacokinetic data, calculated by using a two-compartment open body model, were similar for the three intravenous doses: the t 1/2 alpha value was within 0.12 to 0.20 h, the t 1/2 beta value was 1.98 to 2.05 h, the central distribution volume (Vc) was 3.81 to 7.04 liters/1.73 m2, and the apparent volume of distribution at steady state (Vdss) was 9.12 to 13.36 liters/1.73 m2, i.e., 13.7 to 20.2% of the body weight. From 82.0 to 97.7% of the dose was recovered, in unchanged form, in urine during 24 h. After a single intramuscular dose of 15 mg/kg in the same subjects with normal renal function, the mean peak serum levels, occurring at 0.95 +/- 0.37 h, were 48.28 +/- 11.81 microgram/ml, the t 1/2 beta value was 2.22 +/- 0.16 h, the renal clearance (CR) was 87.5 +/- 9.4 ml/min per 1.73 m2, and 96.9 +/- 12.7% of the injected dose was found in 24-h urine. Pharmacokinetic data were similar for the two routes of administration. In uremic patients, the t 1/2 beta increased according to the severity of renal failure; it was 4.83 h in patients with creatinine clearances (Ccr) within 30 to 60 ml/min per 1.73 m2, 8.42 h for Ccr values within 10 to 30 ml/min, and 18.95 h in hemodialysis patients. During a 4- to 6-h dialysis session, the t 1/2 beta value was 3.65 h and 51% of the drug was removed by dialysis. The apparent volume of distribution at steady state increased in patients with Ccr values below 10 ml/min; serum and renal clearances decreased in uremic patients, and the nonrenal clearances remained constant in all these patients. From these pharmacokinetic results, linear relationships were found between the kinetic data and the biological parameters of the glomerular filtration rate. Dosage schedules were established, adapted to the degree of renal impairment.

Adult↗

Pharmacokinetics of azlocillin in healthy subjects.

The pharmacokinetics of azlocillin were investigated in six healthy subjects with normal renal function. 40.4 to 69.6% of the injected dose was recovered, estimated as unchanged form, in urine during 24 h. After intravenous bolus injection of 15 and 30 mg/kg doses, pharmacokinetic data were calculated, using a two-compartment open body model. The mean distribution serum half-life (T1/2 alpha) was 0.11-0.12 h and the mean elimination serum half-life (T1/2 beta) was 0.79-0.89 h. The volume of the central compartment (Vc) was 7.36-8.01 1/1.73 m2 and the apparent volume of distribution (Vdss) was 14.12-14.32 1/1.73 m2. The mean T1/2 beta after a 30 min i.v. infusion of 80 mg/kg to the same healthy subjects was 1.10 h. Serum clearances (Cs) for 15, 30 and 80 mg/kg were 251.1, 214.0 and 152.9 ml/min/1.73 m2 and renal clearance (Cr) were 99.7, 145.2 and 94.1 ml/min/1.73 m2, respectively. Azlocillin pharmacokinetics were found to be dose dependent. Administration of probenecid increased the terminal serum half-life and the total area under the serum azlocillin concentration-time curve and decreased renal clearance, indicating that azlocillin is eliminated by both glomerular filtration and tubular secretion.

Adult↗

[The use of antibiotic treatment in osteoarticular infections].

The authors emphasise the interest of identification of the germ during bone and joint infections, and recall the main data, often fragmentary, one the diffusion of antibiotics into bone. Concerning the practical use of antibiotics, they emphasise the necessity of basing their treatment on bacteriological examinations before choosing an association of two antibiotics, the effect of which will be regularly assessed by a study of the bactericidal power of the serum.

Aminoglycosides↗

[Antibiotic audit].

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Anti-Bacterial Agents↗

Pharmacokinetics of azlocillin in subjects with normal and impaired renal function.

The pharmacokinetics of azlocillin were investigated in five healthy subjects and in 16 subjects with chronic renal failure. After intravenous bolus injection of a single dose of 30 mg/kg in normal subjects, pharmacokinetic data were calculated, using a two-compartment open body model. The mean distribution serum half-life (T(1/2alpha)) was 0.11 h, and the mean elimination serum half-life (T(1/2beta)) was 0.89 h. The volume of the central compartment (V(C)) was 7.36 liters/1.73 m(2), and the apparent volume of distribution (V(dss)) was 14.15 liters/1.73 m(2), i.e., 21.9% of body weight. The T(1/2beta) after a 30-min intravenous infusion of 80 mg/kg to the same healthy subjects was 1.11 h. Serum clearances (C(S)) for the 30- and 80-mg/kg doses were 215.0 and 152.9 ml/min per 1.73 m(2). The mean renal clearances (C(R)) were 145.2 and 94.1 ml/min per 1.73 m(2) for the respective doses. Between 61.8 and 69.6% of the injected dose was recovered in urine during the first 24 h. The elimination half-life in subjects with chronic renal impairment increased with the degree of renal insufficiency. After a 30-min intravenous infusion of 80 mg/kg the T(1/2beta) values were 2.03, 4.01, and 5.66 h with creatinine clearances (C(cr)) within 30 to 50, 10 to 30, and <10 ml/min per 1.73 m(2), respectively. Urinary elimination was inversely related to the degree of renal impairment. In four patients out of and on a 6-h hemodialysis session mean elimination half-life values were 6.53 and 2.81 h, respectively. The fraction of drug removed by dialysis was 45.8%. The linear relationships between the elimination of half-life (T(1/2beta)) and serum creatinine and the elimination rate constant (beta) and creatinine clearance (C(cr)) provided a basis for adjustment of dosage in renal failure.

Adult↗

Cefoxitin concentrations in the cerebrospinal fluids of patients with meningitis.

The concentrations of cefoxitin in serum and cerebrospinal fluid (CSF) were measured simultaneously in three groups of patients, 12 with aseptic meningitis (group 1) and 17 and 14 with bacterial meningitis (groups 2 and 3). The patients in group 1 received a single intravenous dose of 2 g of cefoxitin without other antimicrobial therapy. In addition to conventional doses of ampicillin or benzyl penicillin, patients in groups 2 and 3 received repeated infusions of 2 g of cefoxitin every 4 h for the first 3 or 4 days of the study and again on day 10. Additionally, group 3 received probenecid in a loading dose of 1 g followed by 0.5 g every 6 or 8 h. Concentrations of cefoxitin in CSF and serum were determined 1 or 2 h after infusion in group 2 and 2 h after infusion in group 3. The concentrations of cefoxitin in CSF did not reach detectable levels (1.56 microgram/ml) in 11 of the 12 patients in group 1. A level of 2.8 microgram of cefoxitin per ml of CSF was found, with an accompanying level of 30 microgram/ml of serum, in patient 12. In the group 2 patients with bacterial meningitis, the mean CSF concentrations were 3.3, 4.7, and 2.9 microgram/ ml on days 1, 3, and 10 of treatment, with simultaneous serum levels of 8, 9, and 8 microgram/ml. At similar times periods, the mean levels of cefoxitin in group 3 patients (with concomitant probenecid) were 8.6, 12.3, and 4.3 microgram/ml of CSF and 57, 35, 27 microgram/ml of serum.

Adolescent↗

Pharmacokinetic comparison of cefroxadin (CGP 9000) and cephalexin by simultaneous administration to humans.

The pharmacokinetic parameters of cefroxadin and cephalexin were compared after simultaneous oral administration of the two cephalosporins to 21 subjects. The influence of the dose, the formulation, and food intake on these parameters was investigated. Both drugs were equally well absorbed from all of the tested formulations; identical percentages of the dose were recovered in the urine in all cases. The elimination half-life of cefroxadin and, consequently, the area under the plasma concentration-time curve were about 10% less than those of cephalexin. Plasma concentrations and cumulative excretion curves of the two drugs were almost superimposable. Food intake had the same effect on both drugs; absorption was slowed, but the amounts absorbed were almost the same as those in fasted subjects.

Adult↗

Sulfinpyrazone kinetics after intravenous and oral administration.

Sulfinpyrazone kinetics has been investigated after intravenous and oral doses. They may be described by a 3-compartment open model. In the body about half the drug is in the plasma or in interstitial fluids, which equilibrated with plasma. Most of the rest is in an extravascular compartment, from which it easily diffuses back to the plasma. About 3% of the dose is still in the body after 24 hr and is located mainly in a deep compartment. After oral administration, sulfinpyrazone is quickly absorbed, largely from the stomach.

Administration, Oral↗

Pharmacokinetics of amoxicillin: Dosage nomogram for patients with impaired renal function.

Amoxicillin pharmacokinetics after intravenous administration were studied in patients with normal renal function, with impaired renal function, and during hemodialysis. The average urinary recovery was 68% in patients with normal renal function. Serum half-life was highly correlated (r = 0.967) with creatinine clearance corrected for body weight. Expected half-life was 71 min for a corrected creatinine clearance of 100 ml/min per 70 kg and 16 h in the anephric patient. Average amoxicillin half-life on hemodialysis was 3.6 h. We present a dosage nomogram for making appropriate adjustments to loading dose based on patient weight and maintenance dose based on corrected creatinine clearance.

Amoxicillin↗

Pharmacokinetics of cefadroxil in normal subjects and in patients with renal insufficiency.

Pharmacokinetics of cefadroxil, a new orally semisynthetic cephalosporin, was studied in 5 subjects with normal renal function and in 20 patients with varying degrees of renal insufficiency. All subjects received 1,000 mg per os in a single dose and the elimination phase was studied. In healthy subjects, elimination half-life (T1/2) was 1.39 +/- 0.06 h. Apparent volume of distribution was 0.305 liters/kg and area under the serum concentration versus time curve AUC was 82.94 +/- 19.98 microgram . h/ml. Peak level averaged 25.72 +/- 4.68 microgram . ml-1 and occurred at 1.20 +/- 0.45 h postingestion. 93.0 +/- 3.6% of the dose was recovered in urine during the first 24 h. Renal and serum clearance averaged 166.7 and 172.4 ml . min-1/1.73 m2, respectively. In patients with renal insufficiency, T1/2 increased to 25.49 h in severe chronic renal failure. Renal impairment did not significantly modify volume of distribution. During a 6- to 8-hour hemodialysis session, antibiotic serum concentrations decreased by 75.4 +/- 5.6%. Dosage schedules could be suggested on the basis of these pharmacokinetic results.

Administration, Oral↗

Serum concentration of human alpha 2 HS glycoprotein during the inflammatory process: evidence that alpha 2 HS glycoprotein is a negative acute-phase reactant.

A nonspecific opsonin function has been ascribed to human alpha 2 HS glycoprotein. Its serum level has been shown to be decreased in trauma patients. Recent studies from this laboratory revealed a heterogeneity among the products obtained in the course of the preparation of the protein. To date, no definitive agreement existed with regard to a molecular homogeneous entity of alpha 2 HS glycoprotein (Ba-alpha 2 glycoproteins). The purpose of the current work was to study the variations in serum level of alpha 2 HS in patients suffering from an acute inflammatory process of bacterial etiology and to determine whether a decrease in alpha 2 HS was accompanied by the appearance of fragments of this protein in the serum. A method of preparing alpha 2 HS was thus developed, using an immune absorbent as a final purification step. In an intermediary step of the preparation, alpha 2 HS was found to bind zinc when metal chelate affinity chromatography was employed. Immunologically and physico-chemically pure alpha 2 HS was obtained. The protein consists of a unique polypeptide chain of about 50,000 daltons and has a unique amino-terminal residue, alanine. However, the protein maintained its molecular integrity with difficulty, and spontaneous fragments ranging from 30,000 to less than 10,000 daltons were produced in some of the preparations. No major modification in the molecular structure of the protein was noted in the sera of subjects suffering from an acute inflammatory process. Serum level of alpha 2 HS and alpha 1 antitrypsin (AT)was determined in 23 patients. When the acute-phase (AP-)reactant alpha 1 AT was increased (difference with normal mean greater than +2 or +3 SD), the sera showed a large decrease in alpha 2 HS (difference with normal mean less than -2 or -3 SD). The serum level of alpha 2 HS, albumin, alpha 2 macroglobulin, and of positive AP-reactants, orosomucoidinal study of seven patients. The results were submitted to a principal components analysis. Alpha 2 HS showed a negative correlation with the AP-reactants alpha 1 AT, orosomucoid, and haptoglobin (P less than 0.05) and a positive correlation with albumin (P less than 0.05); these findings indicate that alpha 2 HS is a negative AP-reactant. In addition, analysis of the principal components confirms thestrong analogy between alpha 2 HS and albumin and indicates that serum level behavior of the AP-reactants during the course of the disease closely depends on the protein studied.

Blood Proteins↗