The effect of formulation on radioiodide thyroid uptake in the hyperthyroid cat

This investigation was designed to compare in vitro dissolution profiles from sodium iodide capsules with radioiodide thyroid uptake in hyperthyroid cats using sodium iodide capsules prepared with a formulation exhibiting a complete release of radioiodide (I-123) in vitro and a formulation with an incomplete release of radioiodide. In vitro dissolution profiles for I-123 sodium iodide capsules with two different formulations were determined using the USP XXIII dissolution test. The two formulations studied in vitro were sodium phosphate dibasic powder with 1% magnesium stearate and calcium phosphate dibasic powder with 3% magnesium stearate. By 20 min after initiation of the dissolution test, over 95% of the I-123 was released from capsules of sodium phosphate dibasic powder. The capsules of calcium phosphate dibasic powder reached 75% at 65 min, with no further release occurring thereafter. There was a statistically significant difference in the dissolution profiles of the two formulations. The thyroid uptake of I-123 from capsules exhibiting complete release and incomplete release of radioiodide was determined in hyperthyroid cats. At 4 hr, the mean percentage thyroid uptake value for sodium phosphate dibasic powder with 1% magnesium stearate (complete release formulation) was 12.0% compared to 9.4% for calcium phosphate dibasic powder with 3% magnesium stearate (incomplete release formulation); at 24 hr, the values were 34.4% compared to 23.7%. The data suggest that the incomplete dissolution profile observed in vitro may correlate with a reduction in the bioavailability of the radioiodide in vivo. However, using the Wilcoxon signed rank test, statistically significant differences did not occur between the complete release formulation and incomplete release formulation at either 4 hr or 24 hr (p > .05). The results of the in vivo study with five hyperthyroid cats were not conclusive due to the variability in response between individual cats.     

Design and performance of a roof integrated solar air heater

This paper discusses the design and construction of a roof integrated solar air heater used in a space heating system for a well insulated house located in Melbourne, Australia. The design of the house and the heat storage system is not discussed and details may be obtained elswhere [1]. The space heating system consists of an array of solar air heaters coupled to a rockbed thermal store located under the floor of the house, such that the rooms are heated by radiation and convection from the floor.     

Differential Scanning Calorimetry of Aspartame-Caffeine Mixture

The possible interaction between aspartame and caffeine was investigated by comparing the thermal behavior, using differential scanning calorimetry, of physical mixtures of aspartame and caffeine along with mixtures, in the same molar ratios, obtained as the co-precipitate. Caffeine was found to form several complexes with aspartame. These complexes were found to be dependent on the molar ratios of aspartame to caffeine. The stoichiometry of the aspartame-caffeine complexes were determined from the enthalpy change of the DSC transitions resulting from the complex formation.     

Physical properties and molecular behavior of chitosan films

Chitosan films, varying in molecular weight and degree of deacetylation, were prepared by a casting technique using acetic acid as a dissolving vehicle. The physicochemical properties of the films were characterized. Both molecular weight and degree of deacetylation affected the film properties. Powder X-ray diffraction patterns and differential scanning calorimetry thermograms of all chitosan films indicated their amorphous state to partially crystalline state with thermal degradation temperature lower than 280-300°C. The increase in molecular weight of chitosan would increase the tensile strength and elongation as well as moisture absorption of the films, whereas the increase in degree of deacetylation of chitosan would either increase or decrease the tensile strength of the films depending on its molecular weight. Moreover, the higher the degree of deacetylation of chitosan the more brittle and the less moisture absorption the films became. All chitosan films were soluble in HCl-KCl buffer (pH 1.2), normal saline, and distilled water. They swelled in phosphate buffer (pH 7.4), and cross-linking between chitosan and phosphate anions might occur. Finally, transmission infrared and ¹³C-NMR spectra supported that chitosan films prepared by using acetic acid as a dissolving were chitosonium acetate films.     

Water based silicone elastomer controlled release tablet film coating V - A statistical approach

The silicone elastomer latex formulated with polyethylene glycol and colloidal silica produced a controlled release film coating on potassium chloride tablets. The release rate of potassium chloride was controlled by the total amount of polyethylene glycol and the weight fraction of polyethylene glycol 8000 and 1450 incorporated in the coating. A mathematical model was developed to quantitate the effect of coating components on the drug release rate using the statistical extreme vertices design. The predictive capability of this functional relationship was tested and validated experimentally.     

Water Based Silicone Elastomer Controlled Release Tablet Film Coating 1: Free Film Evaluation

A latex which is a polymerized and cross-linked product of hydroxyendblocked polydimethylsiloxane and an alkoxysilane has been evaluated as a controlled release tablet film coating system. With adequate reinforcement of colloidal silica, the silicone elastomer latex formed solid elastomeric free films upon drying. Polyethylene glycols of different molecular weights were incorporated in the coating system to enhance the permeability of the silicone elastomer to hydrophilic and ionic species. Free films derived from the three-component silicone elastomer dispersions were evaluated by various physical and chemical methods with respect to their suitability as an aqueous controlled release film coating system.     

A three-dimensional engineering curriculum

This paper examines the recent developments affecting engineering education. The introduction of ABET 2000 criteria, the proliferation of engineering fields, and the changes in the characteristic of engineering teams are considered. It concludes that the traditional engineering curriculum, which is organized almost exclusively along thefields of engineering, is no longer capable of producing engineers for the twenty-first century, and therefore proposes a three-dimensional engineering curriculum, which is based onfunction andemployment sector, in addition to thefield of engineering. Philosophically, this proposed 3-D curriculum shifts engineering education from knowing to doing, from fragmentation to integration, and from convergence to divergence. On the practical level, the strength of the proposed 3-D curriculum lies in it being flexible, adaptable, diverse, and resource-sensitive. The diversity of possible programs resulting from the added dimensions enables engineering programs to develop a niche market, which has become an essential survival strategy.     

A NEW GLASS STONE: Na2O · 3CaO · 6SiO21

Attention is called to a stone of different composition than any heretofore recorded, and but recently possible of identification by petrographic-microscopic means through the work by Bowen and Morey on the system Na₂SiO₂-CaSiO₃-SiO₂. Various ways by which attempts were made to determine the composition of the crystals are described and a summary of the optical properties of these crystals from three sources is given. Probable places for the formation of these stones in the tank are also indicated.