Before starting any in vivo study, it is crucial to ask a series of structured questions that define the scientific, ethical, and regulatory foundation of the research. The first consideration is the scientific objective of the study. Researchers must clearly define whether the goal is to assess safety, efficacy, pharmacodynamics, or device performance, as this determines every other aspect of the study design. Another key question is whether an in vivo model is truly necessary or if alternative in vitro or computational methods could provide sufficient data. This aligns with ethical principles such as the 3Rs—replacement, reduction, and refinement—which guide responsible animal research. Additionally, the selection of the most appropriate species and model system must be carefully justified based on biological relevance and regulatory acceptance.
Further important questions include the statistical design of the study, such as sample size determination and endpoint selection, which directly affect data validity. Researchers must also evaluate whether the study protocol aligns with relevant regulatory guidelines and whether necessary approvals, such as ethical committee review, are in place. Another critical factor is logistical readiness, including availability of facilities, trained personnel, and validated analytical methods. Risk assessment should also be conducted to identify potential study failures or variability sources that could compromise results. Finally, it is important to consider how the generated data will be used in downstream regulatory submissions or product development decisions. Asking these questions before initiation ensures that the in vivo study is scientifically robust, ethically justified, and operationally efficient.
