Abstract
The conventional drug discovery pipeline is characterized by high costs, protracted timelines, and a low success rate. This study explores a novel paradigm for accelerating lead compound identification through a synergistic human-AI co-creation framework, leveraging reinforcement learning (RL) for de novo molecular design and expert medicinal chemistry validation. Our methodology integrates an RL agent, trained on a multi-objective reward function encompassing predicted target affinity, synthesizability, and drug-likeness, with iterative feedback from human medicinal chemists. This co-creative loop allows for the dynamic refinement of molecular generation pathways and the prioritization of promising candidates. We demonstrate that this symbiotic approach significantly enhances the generation of novel chemical entities with superior predicted properties compared to purely AI-driven or traditional computational methods. Subsequent *in silico* and *in vitro* validation confirmed the biological activity and favorable pharmacological profiles of several co-created compounds against a specified therapeutic target. This research underscores the transformative potential of human-AI collaboration in navigating complex scientific challenges, paving the way for more efficient and innovative drug discovery.