Paracetamol tablets are often repackaged into dose administration aids (DAAs) for prn use. Pharmacists have limited information regarding the long-term stability of prn medicines stored in DAAs for extended periods due to infrequent dosing. According to current guidelines, in the absence of specific data, medicines should not be stored in a DAA for longer than 8 weeks.Aim:
To determine the physicochemical stability of paracetamol tablets repackaged into DAAs and stored for 12 months.Method:
Paracetamol (Panamax) tablets were removed from primary packaging, repackaged into DAAs (Multi Dose Webster-pak) and stored under ambient (25 °C; 60% relative humidity) and accelerated (40 °C; 75% relative humidity) conditions for 12 months. Physical characteristics of the tablets, such as appearance, weight uniformity, thickness, hardness, friability, disintegration and dissolution rates were evaluated at baseline, 3, 6 and 12 months. Chemical stability was confirmed by high performance liquid chromatography.Results:
All compendial requirements for physical stability were met for tablets stored under ambient and accelerated conditions over the 12-month period. Chemical stability was confirmed, with paracetamol content in the tablets within the British Pharmacopoeial range of 95% to 105% of the labelled amount.Conclusion:
This study provides data on the stability of paracetamol tablets repackaged into DAAs and stored under ambient and accelerated conditions for 12 months. Pharmacists will be able to make risk-benefit assessments and recommend a 12-month expiry on paracetamol prn DAAs.