Levothyroxine sodium – Anhydrous vs. Pentahydrate

[helvella]

If you read about levothyroxine, especially as a medicine, you will see mention of two forms used as the Active Pharmaceutical Ingredient (API) in levothyroxine medicines: levothyroxine sodium (anhydrous) and levothyroxine sodium. Although the second form doesn’t make it clear, it could refer either to the anhydrous form or to a hydrated form. We have to try to interpret from context and any other information present.

There is a genuine difference between levothyroxine sodium (anhydrous) and the most common hydrated form, levothyroxine sodium pentahydrate.

Five water molecules are attached to the levothyroxine sodium molecule in the pentahydrate: none in the anhydrous

The rest of this document includes formatting and images which I cannot include here. Hence, here is a link to a PDF:

dropbox.com/s/pqwuga75fxvkd...

[helvella Administrator Thyroid UK]

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