Stability of a flavored formulation of acetylcysteine for oral administration

The chemical and physical stability of a flavored solution of acetylcysteine stored at room temperature or under refrigeration for up to 35 days in amber plastic prescription bottles were studied.

The flavored acetylcysteine solution was prepared by adding a sweetener and a strawberry creamsicle flavoring to acetylcysteine solution 10% to a final nominal acetylcysteine concentration of 86.5 mg/mL. Six identical samples of the formulation were prepared in amber plastic prescription bottles. Three bottles were stored at room temperature (23-25 degrees C) and the other three were stored in the refrigerator (3-5 degrees C). Immediately after preparation and at 7, 14, 21, 28, and 35 days, each sample was assayed in duplicate by high- performance liquid chromatography. Stability was defined as the retention of at least 90% of the initial drug concentration.

On day 35, the refrigerated acetylcysteine samples retained 96.7% of their initial concentration. The samples stored at room temperature retained 92.5% of their initial concentration.

A flavored oral formulation of acetylcysteine 86.5 mg/mL was stable for at least 35 days when stored at room temperature and in the refrigerator in amber plastic bottles.