Alternatives to the Use of Animals in Drug Research

Introduction & rationale

• Definition — Alternatives to animal experimentation are scientific methods and tools that replace, reduce or refine the use of live vertebrate animals in drug discovery, development and toxicity testing, while still meeting regulatory standards of efficacy and safety evidence.
• Two-fold rationale — Ethical — each animal has a right to life that humans should not take away; and scientific/economic — animal models are imperfect predictors of human response, whereas alternatives are faster, cheaper and higher-throughput.
• The modern challenge — New drugs can increasingly be evaluated in vitro, in silico (by computer) or by human microdosing, raising the question of whether whole-animal studies remain strictly necessary.
• Scope across the pipeline — Discovery → in silico screening + HTS + cell-free/cell-based assays; preclinical → in vitro ADME/Tox (CaCo-2, PAMPA, liver microsomes); clinical → human microdosing / Phase 0.
• Conceptual boundary — Animal use is minimised, not abolished — alternatives are mandatory where a validated replacement exists; otherwise refinement and reduction apply.