Making Pharmaceutical Administration Evidence Cumulative: What PBPK Teaches Us About Building Knowledge Across PBPK.

Pharmaceutical administration studies determine whether a medicine can be prepared, held, and delivered without unacceptable loss of quality. Their conclusions are essential to product instructions, yet the underlying evidence is difficult to use beyond the product and conditions originally tested. This letter contrasts that pattern with physiologically based pharmacokinetic modelling, a field in which system, drug, and study information are represented separately and the purpose and limits of model use are made explicit. Administration science does not require a PBPK model. It does, however, need records that preserve the relationships among product and formulation attributes, administration-system components, preparation and use conditions, measured outcomes, and the boundaries of the experiment. Standardized, structured records would not remove the need for product-specific studies. They would make previous work easier to interpret, reveal when further testing is necessary, and allow administration evidence to contribute to cumulative pharmaceutical knowledge.