Samuel Arnold

Assistant Professor in Department of Pharmaceutics & Division of Allergy and Infectious Diseases

Department of Pharmaceutics, Pharmaceutics Faculty, School Faculty

Telephone: (206)-221-3441


Website: Linkedin

Accepting Students to Lab: Yes


  • Bachelor of Science in Biochemistry, University of Colorado
  • Ph.D. in Pharmaceutics, University of Washington

Research Interests

  • Infectious Diseases, Pharmacokinetic-pharmacodynamic modeling for treatment of enteric infections
  • Enteric disease induced changes in drug disposition
  • Improved preclinical models of drug disposition in the GI

Courses Taught

  • PCEUT531
  • PCEUT532
  • PCEUT506


Dr. Samuel Arnold received a bachelor’s degree in biochemistry from the University of Colorado in 2009 and obtained a PhD from the University of Washington in 2015. He trained with Dr. Wesley Van Voorhis in the Division of Allergy and Infectious Diseases at the University of Washington, and Dr. Arnold joined the Department of Medicine as an Acting Assistant Professor in 2019.

Dr. Arnold’s research has predominantly focused on drug development for enteric infections. While there has been a substantial reduction in diarrhea associated mortality over the past decade, diarrheal diseases continue to be a major global health concern (second leading cause of death in children < 5 years old). The remarkable reduction in disease burden can be attributed to many factors, and this includes vaccine rollout for rotavirus. However, with a reduction in rotavirus infections, there has been a concurrent increase in the proportion of diarrheal diseases attributed to other etiological agents of disease (e.g., Cryptosporidium and Shigella.) Dr. Arnold’s research applies principles from drug metabolism and pharmacokinetics (DMPK) and pharmacology to preclinical and clinical drug development for enteric infectious diseases. This work includes the development of in vitro and in vivo models for cryptosporidiosis and shigellosis. As a member of the Bill & Melinda Gates Foundation Cryptosporidium Drug Accelerator (CryptoDA), Dr. Arnold led a successful effort to identify pharmacokinetic/pharmacodynamic (PK/PD) relationships for anti-cryptosporidiosis drugs. Due to the gastrointestinal localization of the pathogen, this work required a non-traditional experimental approach to identify exposure-response relationships. In addition, Dr. Arnold supported an anti-cryptosporidiosis clinical trial in Malawi ( #NCT03341767) that investigated clofazimine as a potential anti-cryptosporidiosis treatment. Subsequent analysis of the data from this trial has demonstrated for the first time that a participant’s diarrheal status is associated with therapeutic exposure. Based on these results, the Arnold lab is working to develop pharmacokinetic models that can predict the impact of diarrhea on drug exposure prior to human dosing.

Selected Publications