James John Benedict
Procter & Gamble
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Featured researches published by James John Benedict.
Clinical Pharmacology & Therapeutics | 1982
Gerald J Yakatan; Wesley J Poynor; Robert L Talbert; Benjamin Franklin Floyd; Candice L. Slough; Robert Stanley Ampulski; James John Benedict
Carbon 13–labeled clodronate disodium was given to healthy adult men by intravenous infusion and orally in a crossover design. Serum and urine levels were determined as a function of time by isotope‐ratio mass spectrometry. Clodronate disodium (Cl2MDP) is primarily excreted unchanged by the kidney; more than 80% of the intravenous dose was recovered within 48 hr. The serum concentration‐time curve over the first 8 hr after intravenous dosing appears biexponential with the disposition phase having a harmonic mean half‐life (t½) of 2 hr. The mean serum clearance was found to be 1.4 ml min−l kg−l and the apparent volume of distribution was approximately 25% of body weight. Simulations and computer fitting of the cumulative urinary excretion and urinary excretion rates based on the biexponential serum decay curve demonstrated the presence of a slow disposition component with a t½ of 12.8 hr. Thus, the disposition kinetics of Cl2MDP appear to be triexponential, although the slowest component is not of major significance after a single dose and could not be verified because of a lack of serum data after 8 hr. Cl2MDP is poorly absorbed with an absolute bioavailability of only 1% to 2%.
Calcified Tissue International | 1983
James P. Yesinowski; James John Benedict
SummaryHigh-resolution31P NMR spectroscopy is shown to be a potentially valuable new method for monitoring the spontaneous precipitation of calcium phosphates from metastable supersaturated solutions. An apparatus capable of pH-statting the sample in a spinning 20 mm NMR sample tube is briefly described. The spontaneous precipitation of dicalcium phosphate dihydrate, CaHPO4· 2H2O, pH-statted at pH 5, is characterized by a base-uptake curve which follows the decrease in the intensity of the solution31P resonance. The precipitation of amorphous calcium phosphate at neutral pH, which exhibited an induction period of ∼ 10 min, was also studied. No evidence of NMR peaks from transient clusters or the initial colloidal solid phase has been seen.
Journal of Magnetic Resonance | 1982
James P. Yesinowski; Richard Joseph Sunberg; James John Benedict
Abstract An apparatus is described which permits the acquisition of NMR spectra from spinning 20-mm sample tubes while: (1) constantly monitoring the pH; (2) adding reagents to maintain constant pH (pH-statting); (3) efficiently mixing the added reagent. The apparatus was built to study the spontaneous precipitation of calcium phosphates from supersaturated solutions using 31 P NMR. Other applications include the rapid determination of NMR titration curves, and the minimization of temperature gradients in large sample tubes. The apparatus was used to measure the 31 P chemical shift titration of dilute phosphoric acid, which yielded accurate shifts for the three species of protonated orthophosphate ion. The bulk magnetic susceptibility of 85% H 3 PO 4 relative to a dilute aqueous sample was also measured, and is shown to contribute significantly to chemical shift measurements.
Archive | 1985
James John Benedict; Christopher Mark Perkins
Archive | 1976
James John Benedict
Archive | 1994
Christopher Damien; James John Benedict; James William Poser
Archive | 1992
James William Poser; James John Benedict
Archive | 1986
James John Benedict; Charles Raymond Degenhardt; James William Poser
Archive | 2008
James John Benedict; Christopher Damien
Archive | 1987
James John Benedict; Rodney Dean Bush; Richard Joseph Sunberg