Kidney stone drug nears FDA approval

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  • News of the Week

    cal Societies of America, Canada, and Ontario, held recently in To-ronto. This use of a pheromone, to attract good bugs that will devour other pests, is something of a rever-sal of the ordinary strategy for employing insect pheromones. Typ-ically, they have been used to lure pests into traps where they could be destroyed. In Aldrich's novel agricul-tural ploy, the predatory soldier bug would be lured into a field where perhaps a wide variety of other crea-tures 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, ac-cording to Aldrich.

    The attractant is a blend of five relatively simple compounds, all of which are commercially available, Al-drich says. The bulk of this mix consists of CE)-2-hexenal and (+)-a-terpineol, and the minor compo-nents 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 tech-nical name of Podisus maculiventris.

    Aldrich says this new pheromone mix could prove successful because the soldier bug tends to relish in-sects that are in the larval stage, which is when they do the most damage. During the past summer, the attractant drew some 1300 sol-dier bugs into traps, Aldrich notes, adding that wider field trials will be required to ensure that the attract-ant can really do its job.

    Kidney stone drug nears FDA approval A drug effective in preventing pain-ful kidney stones in certain patients is near final marketing approval from the Food & Drug Administration, according to Charles Y. C. Pak, di-rector 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, so-dium cellulose phosphate (SCP), through 15 years of clinical trials. SCP will be prepared and marketed by Mission Pharmacol Co., San Antonio.

    SCPpurified wood fiber with phosphate groups attachedblocks

    8 C&EN Dec. 6, 1982

    kidney stone formation in those pa-tients who absorb abnormally high amounts of calcium from food in the intestine. The drug, which is in-ert and not absorbed into the blood-stream, binds calcium, restoring nor-mal absorption from the intestine and resulting in lower urinary cal-cium 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. pharma-ceutical company was interested in developing the drug, Pak says, be-cause 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 mak-ing them good candidates for treat-ment 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 depart-ments as chemistry, civil engineering, physics, mechanical engineering, macromolecular science, and metal-lurgy 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 physi-cal chemistry professor Irvin M. Krieger, and the associate director will be polymer science professor Scott E. Rickert. "Adhesives, coat-ings, and sealants are low-technology industries," says Krieger. "They need to become high-technology indus-tries. 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 seal-ants 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 fur-nish representatives to the three technical committees. Technical committees will approve research

    University of Texas, FDA, the Na-tional Institutes of Health, and Mis-sion Pharmacol with bringing SCP to its current state of development. NIH supported Pak's research, and FDA invited the new drug applica-tion. 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 differ-ent conditions leading to kidney stones, and he stresses that SCP could do more harm than good in patients who do not have increased calcium absorptionby 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 ab-sorption, and we don't know where the retained calcium is deposited," Pak says. He favors the more selec-tive action of SCP.

    ^search center formed proposed in each area. Four spon-sors already signed up are General Electric, the Glidden-Durkee divi-sion of SCM Corp., PPG Industries, and Cleveland sealants producer Tremco. The center will seek other support of specific projects from gov-ernment agencies and trade assoc-iations.

    The new center will start up with-out its own space, staff, or equip-ment. Some idea of how it may de-velop comes from the long-estab-lished center for electrochemical studies at Case Western Reserve, which has acquired laboratories, spe-cial equipment, and technicians to maintain the equipment for students and to do special projects for indus-trial sponsors. The new center will organize core courses in such fields as adhesives, coatings, and sealants and surface science and instrumen-tal 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, exam-ining the controversial concept of yield stress and the value of rheol-ogy to predict materials performance; and space-age materials, which come under stringent demands for aircraft, spacecraft, and missile uses.

    Kidney stone drug nears FDA approval