Senior Scientist, Pharmacokinetics

Merck • Upper Gwynedd Township, PA

2d • $117,000 - $184,200 • Onsite

About The Position

The DMPK group at our company's Research Laboratories is seeking a highly skilled and driven Senior Research Scientist (R3) with expertise in biotransformation (metabolite identification), mass spectrometry, and mechanistic enzymology. The successful candidate will leverage deep knowledge of drug metabolism and biotransformation mechanisms to design and execute experiments that identify and characterize drug metabolites, elucidate metabolic pathways, and solve complex metabolism-related challenges, supporting our drug discovery and development pipeline. You will work in a highly collaborative environment, influencing cross-functional teams through a deep understanding of how enzyme-mediated metabolic processes impact drug efficacy, safety, and developability, while driving innovation and maintaining the highest standards of scientific rigor.

Requirements

• Ph.D. in Pharmaceutical Sciences, Analytical Chemistry, Biochemistry, Pharmacology, or a related field, or a Master’s degree in a relevant discipline with 4+ years of industry experience leveraging mass spectrometry for metabolite identification. (Candidates anticipating Ph.D. completion in < 2 months are welcome to apply.)
• Clear understanding of biotransformation pathways and metabolite identification workflows (e.g., in vitro assays, metabolite isolation techniques, mass spectral analysis), with demonstrated ability to design experiments that elucidate metabolite structures and identify the enzymes involved in their formation (including bioactivation pathways).
• Strong written and verbal communication skills, with experience translating complex analytical data into clear, actionable conclusions and presenting findings to diverse scientific audiences.
• Proficiency in LC–MS operation, maintenance, and troubleshooting.
• Ability to work effectively on cross-functional teams and collaborate across disciplines (chemistry, biology, toxicology, etc.) to advance project goals.
• Excellent organizational skills, with the capability to manage multiple experiments or projects simultaneously, meet deadlines, and adapt to evolving priorities in a fast-paced environment.
• ADME
• Biochemical Assays
• Detail-Oriented
• Drug Metabolism
• High Resolution Mass Spectrometry (HRMS)
• Liquid Chromatography-Mass Spectrometry (LC-MS)
• Mass Spectrometry Analysis
• Metabolite Identification
• Pharmacokinetics
• Teamwork

Nice To Haves

• Expertise in enzyme kinetics and factors influencing systemic metabolic rates and routes (e.g., drug–drug interactions, pharmacogenomic variations).
• Understanding of pharmacokinetic/pharmacodynamic (PK/PD) relationships and an appreciation of how parent drug and metabolite exposure levels impact efficacy and safety endpoints.
• Track record of scientific achievement through peer-reviewed publications and presentations at scientific conferences.
• Familiarity with regulatory guidelines on drug metabolites (e.g., ICH M3(R2) and FDA MIST guidance) and their implications for drug development.
• Familiarity with advanced high-resolution mass spectrometry platforms (such as time-of-flight [TOF/Q-TOF] and Orbitrap systems) and their application to metabolite identification and structural elucidation
• Familiarity with the preparation, handling, and analysis of radioactive samples and the use of instrumentation for radioactivity measurements.
• Current Employees apply HERE
• Current Contingent Workers apply HERE
• US and Puerto Rico Residents Only:
• San Francisco Residents Only: We will consider qualified applicants with arrest and conviction records for employment in compliance with the San Francisco Fair Chance Ordinance
• Los Angeles Residents Only: We will consider for employment all qualified applicants, including those with criminal histories, in a manner consistent with the requirements of applicable state and local laws, including the City of Los Angeles’ Fair Chance Initiative for Hiring Ordinance
• Search Firm Representatives Please Read Carefully
• Merck & Co., Inc., Rahway, NJ, USA, also known as Merck Sharp & Dohme LLC, Rahway, NJ, USA, does not accept unsolicited assistance from search firms for employment opportunities. All CVs / resumes submitted by search firms to any employee at our company without a valid written search agreement in place for this position will be deemed the sole property of our company. No fee will be paid in the event a candidate is hired by our company as a result of an agency referral where no pre-existing agreement is in place. Where agency agreements are place, introductions are position specific. Please, no phone calls or emails.
• Employee Status:
• Regular
• Relocation:
• Domestic
• VISA Sponsorship:
• No
• Travel Requirements:
• No Travel Required
• Flexible Work Arrangements:
• Not Applicable
• Shift:
• Not Indicated
• Valid Driving License:
• No
• Hazardous Material(s):
• N/A
• Job Posting End Date:
• 06/5/2026
• A job posting is effective until 11:59:59PM on the day BEFORE the listed job posting end date. Please ensure you apply to a job posting no later than the day BEFORE the job posting end date.
• Requisition ID:R397962

Responsibilities

• Apply strong enzymology knowledge by designing and conducting targeted in vitro/in vivo studies using sub-cellular fractions, hepatocytes, recombinant enzymes and radiolabeled isotopes (3H, 14C) to elucidate biotransformation pathways and identify the enzymes responsible for metabolite formation and bioactivation.
• Independently design and execute experiments to profile and structurally elucidate drug metabolites, leveraging high-resolution and triple quadrupole mass spectrometers for purpose driven metabolite identification.
• Optimize sample preparation, chromatographic separation, and mass spectrometric techniques to improve metabolite detection and structural elucidation sensitivity and throughput.
• Interpret metabolite profiling data within the broader ADME/DMPK context, applying enzymology insights to correlate metabolic routes and rates with overall drug clearance, pharmacokinetics, and safety implications.
• Effectively document experiments and results, ensuring high-quality data capture, and clearly communicate scientific findings in electronic lab notebooks, reports, and presentations.
• Work closely with interdisciplinary teams to integrate metabolite identification results and mechanistic insights into broader project strategies and decision-making.
• Contribute to maintaining efficient lab operations, including instrument upkeep, compliance with safety and quality standards, and mentoring junior staff.

Benefits

• medical, dental, vision healthcare and other insurance benefits (for employee and family)
• retirement benefits, including 401(k)
• paid holidays
• vacation
• compassionate and sick days

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: Ph.D. or professional degree