Biomedical subjects

D Sandor

Publications and source records attributed to D Sandor.

4 recordsLinked to original sources

PubMed1988

Quantitative selected ion monitoring processing system: software and hardware for the automated collection and analysis of selected ion monitoring data acquired for use in pharmacokinetic studies.

The Quantitative Selected Ion Monitoring Processing System (QSIMPS) is a collection of software and hardware which was designed with the capacity to analyze 30,600 samples per year in support of pharmacokinetic studies. On a per sample basis, QSIMPS was designed to inject a sample into the GC, control the GC divert valve, collect selected ion monitoring data, identify the peaks for the drug and one metabolite and each compound's reference standard, fit the peaks to a relevant chromatographic model, calculate chromatographic features of merit, calculate the peak heights and ratio of the drug and its reference standard and the metabolite and its reference standard, and, using calibration data, convert the ratio to an amount of drug. On a per tray (batch) basis, QSIMPS was designed to fit all the peak height ratios from the calibration standards to either a linear equation, or a generalized nonlinear isotope dilution equation, report a statistical analysis of the fit, and, using aliquot factors, convert the measured amount of drug into concentrations. On a per project basis, QSIMPS prints reports summarizing statistical data on the calibration standards and the quality assurance samples, and prints reports presenting the concentration data as a function of, for examples, subject, drug treatment, time postdose, etc., along with other ancillary data such as subject sex, weight, species, etc. In addition, QSIMPS can fit the concentration data to a number of common pharmacokinetic model-derived equations, and report the resulting pharmacokinetic parameters along with a statistical comparison of the parameters.

Chromatography, Gas↗

PubMed1985

Pharmacokinetics and pharmacodynamics of intravenous cibenzoline in normal volunteers.

The pharmacokinetics of intravenous (IV) cibenzoline were studied in six healthy male volunteers ranging in age from 51 to 78 years. The subjects received intravenous (IV) cibenzoline 100 mg over 20 minutes, and plasma and urine specimens were collected for 48 hours. Cibenzoline plasma concentrations at the end of the infusion ranged from 730 to 1,420 ng/mL and exhibited triexponential decline thereafter. The following mean model independent pharmacokinetic parameters were calculated from the plasma and urine concentration data: terminal half-life, 9.8 hours (range, 8.5-11.9); plasma clearance, 523 mL/min (range, 387-687); volume of distribution, 445 L (range, 328-506); and renal clearance, 289 mL/min (range, 202-334). Approximately 31% to 59% of the dose was recovered unchanged in the urine in 48 hours. A triexponential pharmacokinetic equation with zero order input was used to curve fit the plasma and urine data, and the model-dependent parameters agreed well with the model-independent estimates. A hysteresis loop was observed in the relationship between cibenzoline plasma concentration and QRS prolongation, indicating an initial lag between plasma concentration and effect after IV administration. Based on these results, the following preliminary dosing regimen was proposed to rapidly achieve and maintain therapeutic plasma concentrations equal to or slightly greater than 200-400 ng/mL: 0.25 mg/kg/min IV bolus over one minute followed by 1-1.5 mg/kg/hr for one hour and 0.2-0.4 mg/kg/hr for long-term infusion.

Aged↗

PubMed1984

Age and cibenzoline disposition.

Oral cibenzoline kinetics were followed in 36 healthy subjects aged from 22 to 78 yr divided into groups of six subjects per decade between 20 and 80 yr. Each received a single, oral, 160-mg dose of cibenzoline. Blood and urine samples were collected for 72 hr. Cibenzoline plasma and urine concentrations were measured by HPLC. Maximum plasma cibenzoline concentrations (Cmax) ranged from 283 to 1100 ng/ml and occurred 1 to 2.5 hr after dosing. Apparent oral clearance (ClT) ranged from 401 to 1677 ml/min and the t 1/2 ranged from 5.9 to 13.4 hr. Nonrenal clearance (ClNR) ranged from 65 to 1113 ml/min, renal clearance (ClR) ranged from 165 to 645 ml/min, and 31% to 86% of the dose was recovered unchanged in urine (Xu). The volume of distribution (Vd) was large, ranging from 236 to 948 l. There was a significant relationship between age and the following kinetic parameters: Cmax, Xu, t 1/2 (all of which increased with age), ClT, ClR, ClNR, the terminal elimination rate constant beta, and Vd (which decreased with age). Mean ClT was 999 +/- 371 ml/min in the 20- to 30-yr age group and was 465 +/- 78 ml/min in the 70- to 80-yr age group. The change in ClT with age resulted from a decreased in both ClR and ClNR. Mean t 1/2 varied from 7 hr in the youngest group to 10.5 hr in the oldest group. The age-related changes in cibenzoline kinetics occurred over the entire age range studied and the relationship between age and these kinetic parameters appeared to be linear.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗

PubMedDate not supplied

The disposition and metabolic fate of 14C-cibenzoline in man.

The disposition and metabolic fate of cibenzoline (CBZ) following single oral 153-mg doses of 14C-CBZ succinate were studied in five healthy adult males. The mean maximum plasma radioactivity of 386 ng eq/ml occurred at 2.4 hr after administration. The mean half-life, determined from the 14C plasma concentration and urinary excretion rate data, was 13.1 and 14.8 hr, respectively. The mean maximum CBZ concentration was 196 ng/ml at 1.2 hr post-dose. The mean half-life, determined from the plasma concentration and urinary excretion rate data, was 7.2 and 7.3 hr, respectively. The mean total clearance of radioactivity and CBZ was 300 ml/min and 1224 ml/min, respectively, due to elimination via both renal and nonrenal pathways. The only unconjugated metabolite in the plasma was 4,5-dehydrocibenzoline which, together with other unidentified metabolites, is presumed responsible for the longer observed half-life for total radioactivity. Approximately 75% of the dose was recovered in the urine in the first 24 hr after dosing, 80% of which was present at CBZ and known metabolites. After 6 days, a mean of 85.7% of the dose was excreted in urine and 13.2% in feces. The predominant excreted compound was CBZ (55.7% of the dose) in the 0-72 hr urine. Although several metabolites were identified in urine samples, none were found in substantial amounts relative to the parent drug. Two of these substances showed slight antiarrhythmic activity, whereas the 4,5-dehydro metabolite, representing approximately 4% of radioactivity in urine, was inactive.

Adult↗