Those originally employed were based either on the fusion of the PCE to a tumour specific antibody (Antibody-Directed Prodrug Therapy, ADEPT) or on the delivery of the gene encoding the PCE using viral or non-viral vectors (Gene-Directed Enzyme Prodrug Therapy, GDEPT).
Urea is widely used in fertilizers as a source of nitrogen and is an important raw material for the chemical industry. Friedrich WÃ¶hler's discovery in 1828 that urea can be produced from inorganic starting materials was an important conceptual milestone in chemistry.
Commercial grade urea, which is made up of synthetic ammonia and carbon dioxide when subjected to high heat can be produced as a liquid or solid and is being used in fertilizer and DEF. For DEF purposes itâs most commonly produce in the prill/granular form and is transported by super sacks or bulk rail car.