The long-term objective of the proposed work is to provide physicians and others in the field of preventive health care delivery with an inexpensive and reliable biochemical test to measure patients' exposure to tobacco smoke. At present, a reliable test of this type is not available on a commercial basis. Cotinine, a metabolite of nicotine, has been selected as the product to measure because of its chemical stability, specificity as a marker, and relatively long circulating halflife. Having access to this test will enhance the process of smoking abatement, whether gradual reduction techniques (e.g., nicotine fading) or abrupt withdrawal are employed, and the test can also be employed to emphasize to patients that tobacco smoke products are actually being absorbed into the system.As a first step, an enzyme-linked immunosorbent assay (ELISA) will be developed to measure cotinine; it will be capable of assessing qualitatively the extent of tobacco smoke exposure in saliva and/or urine. Binax, Inc. intends to take advantage of a recent advance in producing polyclonal cotinine antisera that allows for selective removal of "bridge" antibodies that have, in the past, produced high backgrounds and diminished sensitivity. To achieve a detection limit of 10 ng/ml, the cotinine level that separates smokers from nonsmokers, it is proposed to use a simultaneous solid-phase competitive inhibition assay in which binding of enzyme-labeled cotinine antibody to immobilized cotinine is competitively inhibited by cotinine present in the patient sample. In Phase II, Binax, Inc. proposes to carry out a field trial of the test.National Institute on Drug Abuse (NIDA)
