PROJECT SUMMARY This Administrative Supplement to ongoing R35GM140835 award is to seek for purchasing a new liquid chromatograph (LC) system that will be used to determine the purity of novel recombinant microRNAs (BioRNAs) generated through in vivo fermentation production and accurately quantitate target xenobiotic/drugs and metabolites in complex biological samples. These studies are critical elements in the MIRA award which will establish the role and importance of microRNAs in posttranscriptional regulation of xenobiotic metabolism and disposition.