SUMMARYThe stability of an oral formulation of 10 mg/ml caffeine citrate (equivalent to 5.03 mg/ml caffeine free base), which was preserved with potassium sorbate, was assessed at a range of temperatures. There was no appreciable change in pH or caffeine content over 1 year, even at storage temperatures of 32d̀C and 45d̀C. A batch‐to‐batch difference in the stability of potassium sorbate was detected, with losses over 1 year of 2 and 11 for two batches at 25d̀C and 10 and 30, respectively, at 45d̀C. The formulation complied with the Antimicrobial Preservative Efficacy test of the British Pharmacopoeia throughout a period of storage at 25d̀C for 1 year. There was no detectable benefit to preservative efficacy by adding 20 w/v sorbitol as an osmotic agent. The formula with no sorbitol may be preferable due to the potential for sorbitol to cause gastrointestinal upset. A shelf‐life of 1 year at room temperature is feasible. The additional precaution of limiting the in‐use storage life to 1 month after opening is recommended to ensure acceptable microbiolog
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