Which of the following is not an example of replacement in animal research?

Replacement in animal research refers to methods that avoid or minimize the use of animals in experiments when alternatives are available. The correct choice highlights an example that does not fit within this definition.

The use of a new analgesic that provides better postoperative pain relief does not represent the concept of replacement, as it still involves the use of animals for testing the analgesic in a research context. In this scenario, animals are still required to evaluate the efficacy and safety of the new drug, thus not providing an alternative to animal use.

In contrast, the other examples showcase clear replacements where animal use is avoided. For instance, using cell cultures to grow immortal cell lines effectively substitutes for whole animal studies, and employing kits for hormone assays avoids the ethical and practical issues tied to bioassays involving animals. Similarly, computer modeling software acts as a substitute for live animal trials in certain pharmacologic studies, reducing the reliance on animal experimentation.

Overall, understanding these distinctions is crucial in the context of the 3Rs (Replacement, Reduction, and Refinement) in animal research, assisting researchers and IACUC members in making informed decisions that align with ethical standards and regulatory guidelines.