LAB TO LABEL Phase II: Development
Phase II determines the feasibility of a compound to become a product.
Field Testing
One to six compounds per year get into the early development stage. Compounds are synthesized in larger quantities, several pounds, and sent to university researchers throughout the country to test for a specific affect and on a specific crop. These tests are done at many locations to determine broad efficacy data and to collect data for potential registration. Efficacy is evaluated in different climatic conditions and soil characteristics.
"Material Safety Data Sheets" (MSDS) are prepared and accompany test samples. MSDSs identify the compound and indicate the proper protective clothing to be worn by the researcher. Physical data are included such as volatility, solubility, and melting and freezing points. Flammable limits and explosiveness data are given. Toxicity data included are acute oral (rat) and dermal (rabbit) LD50s, acute inhalation LC50, eye and dermal irritation and sensitivity. Also included on the sheets are first aid information and disposal procedures.
Manufacturing technology for these compounds are studied for less expensive synthesis pathways and methods that may be used in large scale production. Preliminary cost of production estimates are made and a pilot plant may be built.
Safety Testing
Environmental tests on these compounds are conducted to determine their volatility, breakdown by light and microbes, leaching and adsorption properties, soil dissipation, and flammability and explodability. Formulations are tested for compound and storage stability.
Residue studies on environmental persistence and fate are initiated. As testing progresses, residue studies are expanded to include to livestock, fish, drinking water, milk and eggs, other foods, processed foods and feed, and crops. Data are collected to determine tolerance limits. Ground water monitoring studies are conducted.
Metabolic studies continue on plant and animal metabolism of test compounds. Metabolic breakdown products of test compounds are studied to determine their safety in animals. Mode of action(s) is determined.
Toxicology testing continues. Studies gradually move from acute (short-term, 7-day) toxicity to 21-day studies and later to chronic toxicity (long-term, 90-days to two years). Chronic toxicity studies include feeding, inhaling and neurological effects. As Phase II progresses and compounds show commercial efficacy, tests are conducted on cancer risk potential, oncogenicity and teratogenicity studies. The potential for chromosome or gene damage is determined.
As compounds advance, toxicity data are required to determine any potential effects on wildlife. Toxicity tests are conducted on birds, usually quails and ducks, fish such as sunfish and trout, fresh water invertebrates, estuarine and marine animals such as clams and shrimp, and wild mammals. A key study is determining any bio-accumulation potential through food chains. A potential would immediately eliminate a potential product.
Only about one compound every two to three years gets through Phase II and advances to Phase III Registration. This will be covered in part four of this series.
Lab to Label: