[Development and validation of analytical techniques for the determination of blood biomarkers in preclinical trials. Why and what for?].

New drug discovery involves preclinical studies to demonstrate its effectivity and safety for further tests in humans. This leads to the need to develop technologies that take advantage of the new analytical tools available within a context where the results of the tests carried out are fully documented, under auditable systems of good laboratory practice. This review updates and describes some of the tests carried out in the preclinical stage of the development of a new drug and the current state of the analytical technology used to measure different blood biomarkers of interest. Biomarker parameters were analyzed at the physiological level, considering both the validation regulations of the analytical techniques used for their determination as the problems that arise when trying to apply them, since many of these biomarkers are endogenous compounds in the used matrices.