Effect of antacid on bioavailability of a sustained-release theophylline preparation

The effect of coadministration of an antacid on bioavailability of a sustained-release theophylline tablet preparation (Theo-Dur) was studied by crossover comparison in five young, healthy, nonsmoking volunteers. Water 90 ml, or "high potency" aluminum-magnesium hydroxide antacid (Mylanta II) 10 ml and water 80 ml were administered concurrently with sustained-release theophylline 600 mg. Eleven blood samples were collected over the next 24 hours. Serum was analyzed with high pressure liquid chromatography technique to determine theophylline concentration. Peak serum concentration (Cmax) and time to peak concentration (tmax) were determined, and area under the 24-hour serum concentration-time curve (AUC) was calculated by the trapezoidal rule for each subject at each study interval. The Student's paired t-test was used to compare Cmax, tmax, and AUC for both treatments. A uniform difference was found between groups in Cmax. Cmax was higher in subjects when treated with the antacid (10.45 +/- 3.03 vs. 8.30 +/- 2.90 micrograms/ml, p less than 0.05) than when given theophylline alone. The mean tmax for the two treatments did not differ (10.4 +/- 1.67 h-combination vs. 10.8 +/- 1.1 h-theophylline, p greater than 0.05). Likewise, mean AUC was unchanged by the coadministration of antacid (140.65 +/- 41.6 micrograms/ml.h--combination vs. 155.13 +/- 46.6 micrograms/h--theophylline, p greater than 0.05). The use of a high-potency antacid product did not decrease the extent of theophylline absorption from this sustained-release product, but did increase Cmax and, presumably, rate of absorption. High-potency aluminum-magnesium antacids can probably be used in combination with this sustained-release theophylline tablet without detriment to therapy.     

Electrode-Produced Signal Distortion in Electrophysiological Recording Systems

Although microelectrodes have been in use for many years and there is a wealth of literature concerning their fabrication and application, there is little reported on waveform distortion produced by these electrodes. This paper reports experimental studies conducted to determine the effects of ac electrode polarization in microelectrode recording systems. Electrode materials are examined as well as other system factors such as the use of negative-input-capacitance (NIC) preamplifiers, stimulus isolation units (SIU), and electrode contact integrity.     

A thermodynamic property formulation for ethylene from the freezing line to 450 K at pressures to 260 MPa

A new thermodynamic property formulation based upon a fundamental equation explicit in Helmholtz energy of the form A=A(, T) for ethylene from the freezing line to 450 K at pressures to 260 MPa is presented. A vapor pressure equation, equations for the saturated liquid and vapor densities as functions of temperature, and an equation for the ideal-gas heat capacity are also included. The fundamental equation was selected from a comprehensive function of 100 terms on the basis of a statistical analysis of the quality of the fit. The coefficients of the fundamental equation were determined by a weighted least-squares fit to selected P--T data, saturated liquid and saturated vapor density data to define the phase equilibrium criteria for coexistence, C _v data, velocity of sound data, and second virial coefficients. The fundamental equation and the derivative functions for calculating internal energy, enthalpy, entropy, isochoric heat capacity (C _v), isobaric heat capacity (C _p), and velocity of sound are included. The fundamental equation reported here may be used to calculate pressures and densities with an uncertainty of ±0.1%, heat capacities within ±3 %, and velocity of sound values within ±1 %, except in the region near the critical point. The fundamental equation is not intended for use near the critical point. This formulation is proposed as part of a new international standard for thermodynamic properties of ethylene.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

Use of teronak for the treatment of obesity with and without diabetes mellitus

The anorectic drug teronak (made by "Sandoz") was used in the treatment of 73 obese patients, 34 of whom suffered from diabetes mellitus. The drug is well tolerated and had no side effects. Its positive action on the carbohydrate and lipid metabolism was noted during the treatment. The mean loss of weight after a 12-week treatment constituted 10.1 +/- 0.6 kg.     

Techniques for measuring the alpha-particle distribution in magnetically confined plasmas

Methods are proposed for measuring the alpha-particle distribution in magnetically confined fusion plasmas using neutral-atom doping beams, ultraviolet spectroscopy, and neutral particle detectors. In the first method, single charge exchange reactions, A⁰+He²⁺A⁺ +(He⁺)^*, are used to populate then=2 andn=3 levels of He⁺. The ultraviolet photons from the decaying excited states are Doppler shifted by 5–10 Å from those produced by the thermalized alpha-particle ash. In the second method, double charge exchange reactions, A⁰+He²⁺A²⁺+He⁰, enable fast neutralized alpha particles to escape from the plasma and be detected by neutral particle analyzers. These methods are distinguished from similar techniques of observing plasma impurities in that, in principle, they allow a determination of the dependence of the distribution function on energy and pitch angle, as well as on spatial position. Detector configurations are analyzed, count rates are estimated, and the detector feasibility is discussed. A preliminary analysis of the feasibility of the required neutral beams is presented, and exploratory experiments on existing devices are suggested.     

Type and amount of dietary fat affect relative concentration of cholesterol in blood and other tissues of calves

Sixteen male Holstein calves consumed by nipple a reconstituted milk containing nonfat dry milk and either soybean oil or tallow for 24 weeks. Calves fed milk in this manner (with no dry feed) are functionally nonruminants because the milk bypasses the ruminoreticulum. The fat in these diets contributed about 30% of total dietary calories. The calves consuming soybean oil milk had significantly greater amounts of cholesterol in blood plasma and adipose tissue than did the calves consuming tallow milk.     

The triplet lifetime of poly(phenyl vinyl ketone). A laser flash photolysis study

The photochemistry of poly(phenyl vinyl ketone) in solution has been examined over a temperature range using nanosecond laser flash photolysis techniques. Experiments were performed at low temperatures to eliminate the interference from biradical signals and allow for the separation in time of the behaviour of quencher-free and quencher-containing polymers. For the former the kinetics of triplet decay in toluene-d₈ lead to log $\text{(}\text{A}\text{s}{}^{\mathrm{?1}}\text{) = 9.90 ± 0.50}$ and E_a = (3.56 ± 0.30) kcal mol^?1 where A is the preexponential factor and E_a the activation energy. The extrapolated triplet lifetime at 20°C is 57 ns.     

Decomposition of pyrite and trapping of sulphur in a coal matrix during pyrolysis of coal

The thermal decomposition of pyrite crystals in coal from the Prince Colliery, Cape Breton, Nova Scotia, has been studied to determine both the temperature of decomposition and the distribution of the sulphur liberated into the coal matrix. Under the experimental conditions used, pyrite decomposes to pyrrhotite between 500 and 550 °C. For small (20 μm) crystals embedded in the coal matrix, essentially all of the sulphur liberated by the decomposition of FeS₂ becomes trapped in the matrix within a distance of 15 μm.     

Quality control in a canola crushing plant

A strong emphasis on quality control provides the technical base on which the reputation for the oil and meal products from a crushing plant is established. Most crushing plants in Western Canada now process only canola, the new quality oilseed developed from the former rapeseed. Quality control procedures employed by these plants to contract, grade, purchase and segregate canola seed for processing are described. Quality products are manufactured to meet national standard specifications of quality with the aid of a regular schedule of sampling and laboratory analysis, combined with frequent communication between quality control personnel and plant operators. Operating procedures are established to minimize variability in the quality of oil and meal products resulting from the natural variation in the characteristics of the seed to be processed. Instrumental methods of analysis are being used increasingly to facilitate the analysis of process materials.