Senior Principal Scientist External API Development Chemical Entities

At Bayer we’re visionaries, driven to solve the world’s toughest challenges and striving for a world where ,Health for all, Hunger for none’ is no longer a dream, but a real possibility. We’re doing it with energy, curiosity and sheer dedication, always learning from unique perspectives of those around us, expanding our thinking, growing our capabilities and redefining ‘impossible’. There are so many reasons to join us.

If you’re hungry to build a varied and meaningful career in a community of brilliant and diverse minds to make a real difference, there’s only one choice.

You are an experienced synthetic and process chemist with the ambition to shape the chemical foundation of our R&D pipeline for new chemical entities (NCEs) by designing, developing, and enabling synthetic routes that evolve into robust API manufacturing processes in partnership with our external CDMO network.

In this Senior Principal Scientist (all genders) position within global CMC teams, you define and drive the DS strategy and are accountable for the DS contribution to the overall CMC package. Serving as the central interface between internal stakeholders and external partners, you lead chemical process development and API supply activities, enabling phase-appropriate, scalable, and sustainable manufacturing processes that ensure timely API delivery, robust product quality, and cost efficiency.

• Provide scientific leadership for the design, assessment, and optimization of synthetic routes for new APIs in preclinical and clinical phases, with a focus on speed, quality, cost, sustainability, and process understanding
• Represent Drug Substance (DS) in global CMC development project teams and contribute to key scientific, strategic, and portfolio decisions, while ensuring a coherent two‑way flow of strategy, decisions, risks, and progress between the internal global CMC team and external CDMO activities
• Guide and challenge route design and synthetic methodology choices at external CDMOs, translating SAR‑driven chemistry into scalable routes for preclinical and clinical supply and future production in alignment with the internal DS development strategy
• Oversee external API campaigns for toxicology studies and clinical trials, including planning, risk assessment, supply‑demand alignment, and budget oversight
• Steer process transfers between external partners and into internal development or external manufacturing, ensuring knowledge continuity and phase‑appropriate documentation
• Contribute to robust, phase‑appropriate control strategies. Co‑author and review the Drug Substance sections of regulatory filings (IND/IMPD and briefing documents) and support responses to health authority questions
• Provide CMC DS assessments for in‑licensing opportunities
• Provide chemical expertise and pragmatic troubleshooting across the internal and external manufacturing network. Actively contribute to the chemistry community by sharing knowledge and driving innovation across organizational boundaries

• Ph.D. in Chemistry or a related science, with extensive experience in the pharmaceutical industry, including an understanding of GLP/GMP and regulatory expectations
• Strong background in synthetic chemistry, with an excellent understanding of reagents, methodologies, and reaction mechanisms, plus a solid grasp of analytical techniques
• Experience in the CMC development of peptides is a plus
• Experience in steering external partners (CROs/CDMOs) or working across an external manufacturing network is a clear advantage
• Proven ability to represent chemistry and Drug Substance in interdisciplinary CMC or project teams and to act…