ST. LOUIS, Oct. 15, 2012 /PRNewswire/ -- Sigma-Aldrich® Corporation (Nasdaq: SIAL) today announced that Sigma Life Science, its innovative biological products and services business, initiated a licensing program aimed at contract research organizations (CROs) and pharmaceutical companies for its novel CompoZr ® Transporter Knockout Cell Lines for preclinical ADME screening and safety studies. Complete functional knockouts of transporters in the intestinal cell line (Caco-2) enables identification of critical safety and efficacy characteristics compared to current chemical inhibitor-based assays and more precise determination of a drug candidate's potential drug–drug interactions. Cyprotex, a leading ADME-Tox service company with sites in both the UK and USA, is the first non-exclusive licensee in the program. For more information, visit www.sigma.com/admetox. The U.S. Food and Drug Administration and the European Medicines Agency recently recommended defining a drug candidate's interactions with efflux transporters, which act as doorways for drugs to exit or be expelled from human cells, to ascertain a drug candidate's probable safety profile and potential for adverse drug–drug interactions. Current efflux transporter assays use standard chemical inhibitors that can interact with multiple transporters simultaneously. This may produce an ambiguous representation of a drug candidates true ADME properties in the human body or potential contradictions with other medications. "Complete transporter knockout human cell lines identify efflux transporter interactions unambigously to produce a clearly defined safety profile for a drug candidate. Sigma's CRO and pharma licensing program will facilitate rapid adoption of this superior approach to identifying potential safety issues and meeting the new regulatory guidelines," explains Paul Brooks, Ph.D., Market Segment Manager at Sigma Life Science. The MDR1 (P-gp), BCRP and MRP2 Caco-2 single and double knockout cell lines were confirmed by genomic analysis and functional transporter activity assays. Sigma Life Science generated the cell lines using its CompoZr Zinc Finger Nuclease technology.