Carbon C 14 Lerociclib

**Semantic type:** Pharmacologic Substance

**Definition:** An orally bioavailable radioconjugate composed of lerociclib, an orally bioavailable inhibitor of cyclin-dependent kinase (CDK) types 4 (CDK4) and 6 (CDK6), radiolabeled with the radioisotope carbon C 14, with potential use for evaluating the pharmacokinetic profile of lerociclib. Upon administration, carbon C 14 lerociclib selectively inhibits CDK4 and CDK6, which inhibits the phosphorylation of retinoblastoma protein (Rb) early in the G1 phase, prevents CDK-mediated G1-S phase transition and leads to cell cycle arrest. This suppresses DNA replication and decreases tumor cell proliferation. Labeling of lerociclib with the radioactive tracer carbon C 14 allows for the evaluation of lerociclib's pharmacokinetic profile, including its absorption, distribution, metabolism and excretion (ADME).

**Synonyms:** - 14C-GB491 - 14C-Lerociclib - [14C]GB491