How to represent IV ingredients when solvent is unknown?

I’m looking for advice on how to represent the amounts of IV ingredients when we don’t know which ingredient is the solvent. I know the usual way (per the spec for Medication.ingredient.amount) is a ratio of active ingredient over volume of solvent, e.g. 2g/50ml.

But in our system we just store a list of components with no indication of which one is the solvent. Do we have any options here? I had thought of using “1 bag” as the ratio denominator for every component, but I don’t know if that’s acceptable…

Thank you for reading!

I think our implementation uses a generic denominator of 1 each when bag volume is not known.

FYI - I had logged a prior change request asking for the choice of SimpleQuantity | Ratio for ingredient.amount, but the resolution was to use a denominator, such as “1 tab”. I believe Pharmacy updated the examples, such as http://hl7.org/fhir/STU3/medicationexample0311.xml.html, to reflect that is ok (for an oral medication example).

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Ok, so there is a precedent for using generic denominators. Thank you for the response, I think this is the answer to our problem!