Principal Scientist, Long-Acting Injectable Sterile Product Development
Rahway, NJ - USA
Job Summary
Job Description
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 drugexcipient interactions delivery system performance and manufacturing processes ensuring product quality safety efficacy and patient-centric design.
This role is a Principal Scientistlevel technical leadership position with a primary focus on 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 principal-level LAI formulation scientist providing scientific leadership for the design development and lifecycle management of long-acting injectable drug products 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
Design and interpret studies to understand and control release kinetics stability and performance including:
Drugexcipient and drugpolymer 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 7 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
Drugpolymer and drugexcipient 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 devicedrug product integration including prefilled syringes or delivery systems relevant to LAIs
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:
Cell Culture Process Development Cell Line Development Chemical Engineering Combination Products Finite Element Analysis (FEA) GMP Compliance Pharmaceutical Process Development Pharmaceutical Sciences Project Manufacturing Quality by Design Quality Control Management Quality Management Stability Calculations Strategic Thinking Technology TransferPreferred Skills:
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The salary range for this role is
$173200.00 - $272600.00This is the lowest to highest salary we in good faith believe we would pay for this role at the time of this posting. An employees 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 can apply for this role through (or via the Workday Jobs Hub if you are a current employee). The application deadline for this position is stated on this posting.
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
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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 in place introductions are position specific. Please no phone calls or emails.
Employee Status:
RegularRelocation:
DomesticVISA Sponsorship:
YesTravel Requirements:
10%Flexible Work Arrangements:
Not ApplicableShift:
Not IndicatedValid Driving License:
NoHazardous Material(s):
n/aJob Posting End Date:
08/1/2026*A job posting is effective until 11:59:59PM on the day BEFOREthe listed job posting end date. Please ensure you apply to a job posting no later than the day BEFORE the job posting end date.
Required Experience:
Staff IC
About Company
Merck & Co., Inc., Kenilworth, New Jersey, USA is known as “Merck” in the United States, Canada & Puerto Rico. We are known as “MSD” in Europe, Middle East, Africa, Latin America & Asia Pacific. We are a global biopharmaceutical leader with a diverse portfolio of prescription medicine ... View more