We have been discussing this topic for years, and we need a decision that is limited in scope to what Dion and Michael describe as predictable, deterministic strength properties to support consistent classification with the international release, ONLY when the normalized concentration rules in the international release editorial policies result in non-terminal decimals or periodic values. Without implying measurement accuracy. Each country could define whether they would use multiple axioms or simply reflect the human and usually locally regulated strength representation in terms. This topic is of interest only to countries that are trying to align with the CD level, where the lack of a specified deterministic rounding algorithm impairs our ability to test for clinical drug equivalency when deciding whether to create a local one.
We need a decision, if possible at the April meeting. As far as it is predictable and deterministic, a decision now is better than unpredictability for a few more years. There were proposals from SI, those were rejected by Australia and I think Matt proposed another option. Several requests for clarifications about the SI viewpoint were discussed (in the patch strength representation thread). Canada proposed a deterministic way that is not always intuitive for humans used to basic rounding rules, but the objective is only for machine consumption and classification against international release for CDs. Everyone would adjust the semantic representation to the appropriate level in their context. In Argentina we just used human term representation (but it is a bit contradictory) because users search for lexical patterns (e.g. aten 50 25 would get atenolol 50 mg/table and hydrochlorotiazide 25 mg/tablet much faster than constructing an ECL), while other countries would want to support local natural ECL queries and thus might use multiple axioms (registered strength, international strength, with terms aligned with registered strength, and using international release policies only for classification. Propose the simplest deterministic machine-readable approach, and let’s move on.