269. matrix factor (MF) The ratio of the analyte response in the presence of matrix to the response in the absence of matrix. MF = analyte response in the presence of matrix/analyte response in the absence of matrix.
270. maximum tolerated dose (MTD) Within the context of preclinical toxicology, an MTD study is a high dose used in chronic toxicity testing that is expected on the basis of an adequate subchronic study to produce limited toxicity when administered for the duration of the test period.
271. Medicines and Healthcare products
Regulatory Agency (MHRA) UK agency responsible for ensuring that medicinal products and medical devices work and are acceptably safe.
272. metabolite A product of metabolism; in bioanalysis, this usually refers to a product of the endogenous metabolism, but metabolites can also be products of metabolism of an administered therapeutic or other exogenous substances.