[In vivo imaging for biodistribution and metabolism evaluations of new chemical entities].

Due to numerous technical developments, in vivo imaging is suitable for pharmacokinetic and metabolism studies of new chemical entities as well as for evaluating their pharmacological or biological effects. MRI, nuclear medicine, X-Ray, ultrasound and optical imaging are available for both clinical and experimental imaging with even higher performance. For all these imaging modalities, diagnostic agents are useful to improve contrast and specificity. Specific targeting of biological events is addressed by molecular imaging. From a pharmacodynamic perspective, radiolabeling of a new chemical entity allows in vivo visualization quantitative measure of its biodistribution, its elimination and its specific molecular binding. Non-invasive imaging methods are useful for longitudinal investigations of biological changes. Based on nanotechnologies, specificity of drug delivery can be monitored by imaging. New developments in hybrid imaging technologies as well as multimodal contrast agents reinforce in vivo experimental and clinical proof of mechanism of new chemical entities.