Stability of an extemporaneously compounded levothyroxine sodium oral liquid

Abstract

The stability of levothyroxine sodium in oral liquid dosage forms compounded from commercially available tablets was studied. Levothyroxine sodium oral liquids (25 μg/mL) were prepared from tablets and from powder with and without methylparaben preservative and transferred to amber, high- density polyethylene bottles. Five bottles of each tablet-based formulation were stored at 2-8°C, 23-27°C, and 38-42°C, and five bottles of each powder-based formulation were stored at 38-42°C. On days 3, 8, 14, 22, 31, 61, and 90, samples were taken from each bottle and analyzed for drug concentration by stability-indicating high-performance liquid chromatography. There was significant degradation of levothyroxine sodium in all the formulations. However, the tablet-based formulation without preservative stored at 4°C retained at least 90% of its initial concentration for eight days after compounding. Degradation occurred faster in the tablet-based formulation with preservative. None of the formulations retained ≥90% initial potency by day 14. An extemporaneous oral liquid formulation of levothyroxine sodium 25 μg/mL compounded from crushed tablets was stable for eight days when stored in amber bottles at 4°C.