Download - Kidney stone drug nears FDA approval
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cal Societies of America, Canada, and Ontario, held recently in Toronto. This use of a pheromone, to attract good bugs that will devour other pests, is something of a reversal of the ordinary strategy for employing insect pheromones. Typically, they have been used to lure pests into traps where they could be destroyed. In Aldrich's novel agricultural ploy, the predatory soldier bug would be lured into a field where perhaps a wide variety of other creatures already are present, poised to do economic damage. The soldier bug, which might otherwise fail to concentrate its feeding activities in the infested and hence endangered crop area, would stay close to the right place because of its attraction to the synthetic sex attractant, according to Aldrich.
The attractant is a blend of five relatively simple compounds, all of which are commercially available, Aldrich says. The bulk of this mix consists of CE)-2-hexenal and (+)-a-terpineol, and the minor components include benzyl alcohol, linalool, and terpinen-4-ol, according to a USDA spokeswoman. The soldier bug, which is about 1 cm long, is one of several stink bugs found in North America and goes by the technical name of Podisus maculiventris.
Aldrich says this new pheromone mix could prove successful because the soldier bug tends to relish insects that are in the larval stage, which is when they do the most damage. During the past summer, the attractant drew some 1300 soldier bugs into traps, Aldrich notes, adding that wider field trials will be required to ensure that the attractant can really do its job. •
Kidney stone drug nears FDA approval A drug effective in preventing painful kidney stones in certain patients is near final marketing approval from the Food & Drug Administration, according to Charles Y. C. Pak, director of the general clinical research center and professor of internal medicine at the University of Texas Southwestern Medical School. Pak guided the former orphan drug, sodium cellulose phosphate (SCP), through 15 years of clinical trials. SCP will be prepared and marketed by Mission Pharmacol Co., San Antonio.
SCP—purified wood fiber with phosphate groups attached—blocks
8 C&EN Dec. 6, 1982
kidney stone formation in those patients who absorb abnormally high amounts of calcium from food in the intestine. The drug, which is inert and not absorbed into the bloodstream, binds calcium, restoring normal absorption from the intestine and resulting in lower urinary calcium levels, Pak says. Thus, stone-forming calcium salts are less likely to precipitate from the urine.
Although SCP has been used in Europe since 1963, no U.S. pharmaceutical company was interested in developing the drug, Pak says, because it is "impossible to patent and impractical to market. The drug is a powder rather than a pill and the doses required are grams rather than milligrams." And although there are 1 million kidney stone patients in the U.S., only a quarter of them have increased calcium absorption, and of these less than 100,000 have the severe form of the disorder making them good candidates for treatment with SCP, Pak estimates.
Pak credits cooperation among the
Adhesives and coatings A center for fundamental research in adhesives, coatings, and sealants will open Jan. 1 at Case Western Reserve University in Cleveland. Graduate students in such departments as chemistry, civil engineering, physics, mechanical engineering, macromolecular science, and metallurgy and materials science will take a series of core courses orchestrated by the center and do theses within their own departments on projects supported by industrial sponsors of the center.
The center's director will be physical chemistry professor Irvin M. Krieger, and the associate director will be polymer science professor Scott E. Rickert. "Adhesives, coatings, and sealants are low-technology industries," says Krieger. "They need to become high-technology industries. Our goal is to provide the research, education, and service needed for this transition. He adds, "We need to know why paints peel, why adhesives fail, and why sealants lose their sealing power. This all relates to the way the polymer adheres to a solid surface."
Ultimately, the center hopes to attract six industrial sponsors for each of the three areas, each of whom will give $15,000 per year and furnish representatives to the three technical committees. Technical committees will approve research
University of Texas, FDA, the National Institutes of Health, and Mission Pharmacol with bringing SCP to its current state of development. NIH supported Pak's research, and FDA invited the new drug application. Pak expects FDA to approve the drug's application by Christmas.
Treatment of patients with SCP is an example of selective therapy for kidney stones that corrects the underlying disorder and is less likely to cause side effects, according to Pak. He has identified nine different conditions leading to kidney stones, and he stresses that SCP could do more harm than good in patients who do not have increased calcium absorption—by causing a calcium deficiency, for example.
Pak admits that an existing drug, thiazide, is about as effective as SCP in inhibiting stone formation. "But thiazide doesn't lower calcium absorption, and we don't know where the retained calcium is deposited," Pak says. He favors the more selective action of SCP. •
^search center formed proposed in each area. Four sponsors already signed up are General Electric, the Glidden-Durkee division of SCM Corp., PPG Industries, and Cleveland sealants producer Tremco. The center will seek other support of specific projects from government agencies and trade associations.
The new center will start up without its own space, staff, or equipment. Some idea of how it may develop comes from the long-established center for electrochemical studies at Case Western Reserve, which has acquired laboratories, special equipment, and technicians to maintain the equipment for students and to do special projects for industrial sponsors. The new center will organize core courses in such fields as adhesives, coatings, and sealants and surface science and instrumental analysis.
The first formal activity will be a symposium on the campus Jan. 11 and 12. Subjects will be polymers and interfaces, including roles of interphases in adhesion and effects of substrates on polymer adsorption; rheology and micromechanics, examining the controversial concept of yield stress and the value of rheology to predict materials performance; and space-age materials, which come under stringent demands for aircraft, spacecraft, and missile uses. •