Senior Associate Scientist
Pfizer Inc.
October 22, 2026
Full-time
On-site
United States - Missouri - St. Louis - Chesterfield
$68,600 - $114,300 USD yearly
Clinical Research and Development
Use Your Power for Purpose
At Pfizer, our purpose is to deliver breakthroughs that change patients’ lives. As a Senior Associate Scientist, you will be at the forefront of this mission, working within our Research & Development division. Your role will be pivotal in translating advanced science and technologies into therapies and vaccines that matter most. By leveraging cutting-edge design and process development capabilities, you will help accelerate the delivery of best-in-class medicines to patients globally, ultimately improving their lives.
ROLE SUMMARY
The qualified candidate will join the Analytical R&D organization to enable development of biological therapeutics and vaccines in Chesterfield, MO. They will be responsible for applying analytical methods in the assessment of product quality, detection of impurities, and characterization.
This group performs testing in the R&D and/or regulated settings in support of clinical drug and vaccine candidates. The group performs method development, transfer, verification, and qualification in support of process and formulation development for biotherapeutics and vaccines.
ROLE RESPONSIBILITIES
The qualified colleague is responsible for:
Developing, troubleshooting, and utilizing analytical methodologies to support process development of biotherapeutics, vaccines and oligonucleotides.
Becoming proficient in a breadth of analytical methodologies including HPLC, colorimetric, and electrophoresis assays.
The colleague must work within corporate guidelines and must appropriately record, archive, and report all data. They must also be able to interact effectively with peers and leaders as part of a multi-disciplinary team. The candidate must thrive in a fast-paced environment. Attention to detail, strong organizational skills, the ability to multitask and effective interpersonal and communication skills are required. Documentation of analytical results in technical reports is required.
QUALIFICATIONS
MINIMUM:
Bachelor’s degree in Chemistry, Biochemistry, Biology, or a related field, with 3+ years of relevant experience; or
Master’s degree in Chemistry, Biochemistry, Biology, or a related field, with 0–2 years of relevant experience.
Laboratory experience in a variety of analytical laboratory techniques.
Ability to follow established procedures under minimal supervision.
DESIRABLE:
Experience with Quality Systems and Good Documentation Practices.
Some knowledge of drug development process for progression of biological candidates.
Experience using common AI tools, including generative technologies such as ChatGPT or Microsoft Copilot, to support problem solving and enhance productivity.
Demonstrated curiosity for exploring how these tools can improve outcomes and understanding of responsible AI practices, including risk management and ethical use.
OTHER ATTRIBUTES DESIRABLE:
Excellent documentation skills
Self-motivated and highly effective in a team-based environment
Effective oral and written communication skills
Experience in analysis of large molecules
Experience with laboratory data systems such as Laboratory Information Management Systems
PHYSICAL/MENTAL REQUIREMENTS
Position requires occasional light lifting and periods of standing, sitting or walking.
NON-STANDARD WORK SCHEDULE, TRAVEL OR ENVIRONMENT REQUIREMENTS
None
Work Location Assignment: On Premise
The annual base salary for this position ranges from $68,600.00 to $114,300.00. In addition, this position is eligible for participation in Pfizer’s Global Performance Plan with a bonus target of 7.5% of the base salary. We offer comprehensive and generous benefits and programs to help our colleagues lead healthy lives and to support each of life’s moments. Benefits offered include a 401(k) plan with Pfizer Matching Contributions and an additional Pfizer Retirement Savings Contribution, paid vacation, holiday and personal days, paid caregiver/parental and medical leave, and health benefits to include medical, prescription drug, dental and vision coverage. Learn more at Pfizer Candidate Site – U.S. Benefits | (uscandidates.mypfizerbenefits.com). Pfizer compensation structures and benefit packages are aligned based on the location of hire. The United States salary range provided does not apply to Tampa, FL or any location outside of the United States.
Relocation assistance may be available based on business needs and/or eligibility.
Candidates must be authorized to be employed in the U.S. by any employer.
U.S. work visa sponsorship (such as TN, O-1, H-1B, etc.) is not available for this role now or in the future.
Sunshine Act
Pfizer reports payments and other transfers of value to health care providers as required by federal and state transparency laws and implementing regulations. These laws and regulations require Pfizer to provide government agencies with information such as a health care provider’s name, address and the type of payments or other value received, generally for public disclosure. Subject to further legal review and statutory or regulatory clarification, which Pfizer intends to pursue, reimbursement of recruiting expenses for licensed physicians may constitute a reportable transfer of value under the federal transparency law commonly known as the Sunshine Act. Therefore, if you are a licensed physician who incurs recruiting expenses as a result of interviewing with Pfizer that we pay or reimburse, your name, address and the amount of payments made currently will be reported to the government. If you have questions regarding this matter, please do not hesitate to contact your Talent Acquisition representative.
EEO & Employment Eligibility
Pfizer is committed to equal opportunity in the terms and conditions of employment for all employees and job applicants without regard to race, color, religion, sex, sexual orientation, age, gender identity or gender expression, national origin, disability or veteran status. Pfizer also complies with all applicable national, state and local laws governing nondiscrimination in employment as well as work authorization and employment eligibility verification requirements of the Immigration and Nationality Act and IRCA. Pfizer is an E-Verify employer. This position requires permanent work authorization in the United States.
Pfizer endeavors to make www.pfizer.com/careers accessible to all users. If you would like to contact us regarding the accessibility of our website or need assistance completing the application process and/or interviewing, please email disabilityrecruitment@pfizer.com . This is to be used solely for accommodation requests with respect to the accessibility of our website, online application process and/or interviewing. Requests for any other reason will not be returned.
To learn more about acceptable and prohibited uses of AI during the recruitment process, please review our candidate AI-use guidelines available on Pfizer Careers .
Research and Development
At Pfizer, our purpose is to deliver breakthroughs that change patients’ lives. As a Senior Associate Scientist, you will be at the forefront of this mission, working within our Research & Development division. Your role will be pivotal in translating advanced science and technologies into therapies and vaccines that matter most. By leveraging cutting-edge design and process development capabilities, you will help accelerate the delivery of best-in-class medicines to patients globally, ultimately improving their lives.
ROLE SUMMARY
The qualified candidate will join the Analytical R&D organization to enable development of biological therapeutics and vaccines in Chesterfield, MO. They will be responsible for applying analytical methods in the assessment of product quality, detection of impurities, and characterization.
This group performs testing in the R&D and/or regulated settings in support of clinical drug and vaccine candidates. The group performs method development, transfer, verification, and qualification in support of process and formulation development for biotherapeutics and vaccines.
ROLE RESPONSIBILITIES
The qualified colleague is responsible for:
Developing, troubleshooting, and utilizing analytical methodologies to support process development of biotherapeutics, vaccines and oligonucleotides.
Becoming proficient in a breadth of analytical methodologies including HPLC, colorimetric, and electrophoresis assays.
The colleague must work within corporate guidelines and must appropriately record, archive, and report all data. They must also be able to interact effectively with peers and leaders as part of a multi-disciplinary team. The candidate must thrive in a fast-paced environment. Attention to detail, strong organizational skills, the ability to multitask and effective interpersonal and communication skills are required. Documentation of analytical results in technical reports is required.
QUALIFICATIONS
MINIMUM:
Bachelor’s degree in Chemistry, Biochemistry, Biology, or a related field, with 3+ years of relevant experience; or
Master’s degree in Chemistry, Biochemistry, Biology, or a related field, with 0–2 years of relevant experience.
Laboratory experience in a variety of analytical laboratory techniques.
Ability to follow established procedures under minimal supervision.
DESIRABLE:
Experience with Quality Systems and Good Documentation Practices.
Some knowledge of drug development process for progression of biological candidates.
Experience using common AI tools, including generative technologies such as ChatGPT or Microsoft Copilot, to support problem solving and enhance productivity.
Demonstrated curiosity for exploring how these tools can improve outcomes and understanding of responsible AI practices, including risk management and ethical use.
OTHER ATTRIBUTES DESIRABLE:
Excellent documentation skills
Self-motivated and highly effective in a team-based environment
Effective oral and written communication skills
Experience in analysis of large molecules
Experience with laboratory data systems such as Laboratory Information Management Systems
PHYSICAL/MENTAL REQUIREMENTS
Position requires occasional light lifting and periods of standing, sitting or walking.
NON-STANDARD WORK SCHEDULE, TRAVEL OR ENVIRONMENT REQUIREMENTS
None
Work Location Assignment: On Premise
The annual base salary for this position ranges from $68,600.00 to $114,300.00. In addition, this position is eligible for participation in Pfizer’s Global Performance Plan with a bonus target of 7.5% of the base salary. We offer comprehensive and generous benefits and programs to help our colleagues lead healthy lives and to support each of life’s moments. Benefits offered include a 401(k) plan with Pfizer Matching Contributions and an additional Pfizer Retirement Savings Contribution, paid vacation, holiday and personal days, paid caregiver/parental and medical leave, and health benefits to include medical, prescription drug, dental and vision coverage. Learn more at Pfizer Candidate Site – U.S. Benefits | (uscandidates.mypfizerbenefits.com). Pfizer compensation structures and benefit packages are aligned based on the location of hire. The United States salary range provided does not apply to Tampa, FL or any location outside of the United States.
Relocation assistance may be available based on business needs and/or eligibility.
Candidates must be authorized to be employed in the U.S. by any employer.
U.S. work visa sponsorship (such as TN, O-1, H-1B, etc.) is not available for this role now or in the future.
Sunshine Act
Pfizer reports payments and other transfers of value to health care providers as required by federal and state transparency laws and implementing regulations. These laws and regulations require Pfizer to provide government agencies with information such as a health care provider’s name, address and the type of payments or other value received, generally for public disclosure. Subject to further legal review and statutory or regulatory clarification, which Pfizer intends to pursue, reimbursement of recruiting expenses for licensed physicians may constitute a reportable transfer of value under the federal transparency law commonly known as the Sunshine Act. Therefore, if you are a licensed physician who incurs recruiting expenses as a result of interviewing with Pfizer that we pay or reimburse, your name, address and the amount of payments made currently will be reported to the government. If you have questions regarding this matter, please do not hesitate to contact your Talent Acquisition representative.
EEO & Employment Eligibility
Pfizer is committed to equal opportunity in the terms and conditions of employment for all employees and job applicants without regard to race, color, religion, sex, sexual orientation, age, gender identity or gender expression, national origin, disability or veteran status. Pfizer also complies with all applicable national, state and local laws governing nondiscrimination in employment as well as work authorization and employment eligibility verification requirements of the Immigration and Nationality Act and IRCA. Pfizer is an E-Verify employer. This position requires permanent work authorization in the United States.
Pfizer endeavors to make www.pfizer.com/careers accessible to all users. If you would like to contact us regarding the accessibility of our website or need assistance completing the application process and/or interviewing, please email disabilityrecruitment@pfizer.com . This is to be used solely for accommodation requests with respect to the accessibility of our website, online application process and/or interviewing. Requests for any other reason will not be returned.
To learn more about acceptable and prohibited uses of AI during the recruitment process, please review our candidate AI-use guidelines available on Pfizer Careers .
Research and Development