?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F757%2F&rft.title=Understanding+the+Screening+Process+of+New+Molecules&rft.creator=Hook%2C+James&rft.creator=Kulesza%2C+Kamil&rft.creator=Morawiecki%2C+P.&rft.creator=Wilson%2C+Eddie&rft.subject=Food+and+Drink&rft.description=Globally+there+is+a+huge+market+for+herbicides.+Syngenta+and+its+competitors+spend+large+amounts+of+money+in+trying+to+develop+new+herbicides+which+are+highly+effective+(kills+the+plants+that+the+farmer+wants+to+get+rid+of)%2C+selective+(does+not+harm+the+crops+that+the+farmer+is+trying+to+protect)%2C+safe+(not+harmful+to+humans+or+the+environment)+and+cheap+to+produce.%0D%0AEvery+year+Syngenta+chemists+develop+around+one+thousand+new+compounds+that+could+be+used+as+herbicides.+Accurately+evaluating+the+efficacy%2C+selectivity%2C+safety+and+ease+of+production+of+each+one+of+these+compounds+would+be+extremely+expensive.+Initially+synthesizing+compounds+even+in+tiny+quantities+requires+a+lot+of+work.+Different+compounds+will+then+require+different+levels+of+dosage%2C+may+target+certain+species+of+plants+better+than+others%2C+may+work+more+effectively+in+conjugation+with+different+solvents+etc.+A+huge+amount+of+time+and+money+could+be+spent+optimizing+the+application+of+a+particular+compound%2C+which+then+turns+out+to+be+very+poor+compared+to+existing+herbicide+products+on+the+market.%0D%0AIn+order+to+attempt+to+select+only+the+best+performing+compounds+in+a+cost+effective+way%2C+Syngenta+use+a+screening+cascade.+This+process+begins+by+testing+all+of+the+candidate+compounds+in+laboratory+experiments%2C+referred+to+as+assays%2C+to+see+if+they+can+(e.g.)+target+a+particular+enzyme%2C+or+penetrate+a+leaf.+These+lab+experiments+only+require+a+tiny+quantity+of+each+compound+to+be+synthesized.+Compounds+which+perform+poorly+in+these+first+experiments+are+discarded+from+the+trial.+We+call+this+the+first+screen.%0D%0ACompounds+which+pass+this+first+round+are+then+passed+to+a+second+round+in+which+a+small+amount+of+the+compound+is+applied+to+several+small+pots+containing+a+few+different+species+of+plant.+Compounds+which+perform+poorly+in+this+second+experiment+are+discarded+from+the+trial+process.+We+call+this+the+second+screen.%0D%0AIn+subsequent+screens+larger+quantities+of+the+compounds+are+used+in+the+experiments%2C+which+makes+them+a+lot+more+expensive.+By+using+more+compounds+the+candidate+herbicides+can+be+tested+on+a+larger+range+or+species%2C+at+different+dosages%2C+in+conjunction+with+various+different+conditions%2C+and+with+less+sampling+error.%0D%0AAs+the+screening+process+progresses%2C+the+screens+become+steadily+more+rigorous+and+consequently+more+expensive.+At+the+same+time+the+number+of+compounds+remaining+in+the+trial+goes+down.+Finally+a+small+number+of+compounds+are+taken+to+the+final+level%2C+called+the+field+trial.+In+this+trial+the+compounds+are+applied+outdoors+in+the+way+they+would+be+used+if+they+were+eventually+developed+into+a+commercial+product.&rft.date=2018&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F757%2F1%2Fesgi-syngenta-screening.pdf&rft.identifier=++Hook%2C+James+and+Kulesza%2C+Kamil+and+Morawiecki%2C+P.+and+Wilson%2C+Eddie++(2018)+Understanding+the+Screening+Process+of+New+Molecules.++%5BStudy+Group+Report%5D+++++