Senior Principal Scientist, Long-Acting Sterile Product Development Full-time

Senior Principal Scientist–Level Technical Leadership

The Sterile Product Development group is responsible for the development of parenteral dosage forms, including long-acting injectables (LAIs), across small molecules, peptides, and biologics from preclinical development through commercialization. Our teams enable robust and scalable drug product and delivery solutions through deep scientific understanding of formulation, drug–excipient interactions, delivery system performance, and manufacturing processes, ensuring product quality, safety, efficacy, and patient-centric design.

This role is a Senior Principal Scientist–level technical leadership position with a primary focus on primarily late-stage development of long-acting injectable drug products, including depot formulations, extended-release systems, and injectable sustained-delivery technologies. The successful candidate will serve as a scientific leader across multidisciplinary teams, shaping LAI formulation and development strategy across the portfolio.

Primary Duties

• Serve as a senior principal-level LAI formulation scientist, providing scientific leadership for the design, development, and lifecycle management of long-acting injectable drug products with line of sight to commercialization, including depot, sustained-release, and controlled-delivery parenteral dosage forms.
• Lead LAI formulation and delivery strategy development, including selection and optimization of release mechanisms (e.g., polymer-based depots, suspensions, microspheres, in situ forming systems), excipient systems, and delivery approaches to meet target product profiles
• Provide strategic technical leadership on cross-functional program teams, ensuring alignment of formulation, drug substance properties, delivery system performance, container/closure systems, manufacturability, and clinical use considerations throughout development and with strong line of sight to commercialization.
• Design and interpret studies to understand and control release kinetics, stability, and performance, including:
• Drug–excipient and drug–polymer interactions
• In vitro and in vivo performance relationships
• Physical stability, aggregation, and particle size control
• Syringeability, injectability, and device compatibility
• Support early- and late-stage development programs, including:
• Selection of scalable manufacturing processes for LAIs
• Definition of formulation and process design space
• Support for clinical and commercial process scale-up and validation
• Technology transfer to GMP manufacturing facilities
• Partner closely with Clinical, Non-Clinical, Quality, Regulatory, Manufacturing, and Engineering teams to:
• Define critical quality attributes (CQAs) and critical process parameters (CPPs) relevant to LAI performance
• Support clinical strategy through formulation design and risk mitigation
• Contribute to CMC regulatory submissions and health authority interactions
• Provide scientific oversight and mentoring to junior scientists, fostering capability development in LAI formulation science, experimental design, and data-driven decision making
• Maintain awareness of emerging LAI technologies and delivery platforms, contributing to internal capability assessments, external collaborations, and innovation initiatives aligned with portfolio and organizational strategy

Minimum Education Requirements

• Ph.D. with 8+ years industry experience, or
• M.S. with 10+ years, or
• B.S. with 14+ years in Pharmaceutics, Pharmaceutical Sciences, Chemical Engineering, Biochemical Engineering, Chemistry, Materials Science, or a related discipline

Required Experience and Skills

• Deep expertise in parenteral drug product development, with demonstrated experience in long-acting injectable or sustained-release formulations
• Strong scientific understanding of:
• Controlled-release mechanisms and LAI delivery systems
• Drug–polymer and drug–excipient interactions
• Formulation stability and performance characterization
• Experience applying Quality by Design (QbD) principles and DOE approaches to formulation and process development
• Experience supporting process scale-up, validation, and technology transfer for sterile injectable products
• Working knowledge of CMC regulatory expectations for parenteral and extended-release products, including development-stage and commercial submissions
• Demonstrated ability to lead cross-functional teams, influence strategy, and communicate complex scientific concepts clearly
• Proven mentoring and scientific leadership skills at the senior/principal level

Preferred Experience and Skills

• Experience with LAI-specific platforms, such as polymer depots, microspheres, nanosuspensions, or in situ forming systems
• Experience with device–drug product integration, including prefilled syringes or delivery systems relevant to LAIs
• Experience with late-stage product development, including Ph3 and commercial filings
• Understanding of clinical and patient-centric considerations influencing LAI design (e.g., dosing interval, injection volume, administration route)
• Experience supporting global regulatory filings and health authority interactions
• Track record of contributing to publications, patents, or external scientific collaborations in drug delivery or formulation science

Required Skills:

Biopharmaceutics, Chemical Engineering, Commercialization, GMP Compliance, Innovative Thinking, Interpersonal Relationships, Manufacturing Processes, Materials Science, Materials Technology, Mentorship, Parenterals, Process Characterization, Product Development, Project Leadership, Scientific Leadership, Sterile Injectables, Technical Leadership

Preferred Skills:

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The salary range for this role is

$190,800.00 – $300,300.00

This is the lowest to highest salary we in good faith believe we would pay for this role at the time of this posting. An employee's position within the salary range will be based on several factors including, but not limited to relevant education, qualifications, certifications, experience, skills, geographic location, government requirements, and business or organizational needs.

The successful candidate will be eligible for annual bonus and long-term incentive, if applicable.

We offer a comprehensive package of benefits. Available benefits include medical, dental, vision healthcare and other insurance benefits (for employee and family), retirement benefits, including 401(k), paid holidays, vacation, and compassionate and sick days. More information about benefits is available at https://jobs.merck.com/us/en/compensation-and-benefits.