Validation of the stability of paracetamol in extemporaneously compounded suppositories

Abstract

AbstractBackgroundAlthough compounded pain suppositories have been widely used in medical practice to accommodate specific patients’ needs, few studies have systemically evaluated the stability of compounded pain relief suppositories in different bases.AimThe aim of this study was to conduct long‐term stability studies on two types of compounded paracetamol suppositories under different storage conditions.MethodsSuppositories were compounded in cocoa butter substitute Fattibase® and polyethylene glycol (PEG) bases using a double‐casting fusion method with a dose of 325 mg paracetamol. Suppositories were stored at 4°C and 25°C, and sampled at 0, 7, 14, 30, 90 and 180 days. Samples were first assessed by weight, colour and the morphology of the suppositories. The pH of the extracted solution was measured and the amount of paracetamol was analysed by HPLC.ResultsThe mean weight of the paracetamol suppository in PEG and Fattibase® was 2.21 ± 0.02 and 1.89 ± 0.00 g, respectively. Initial paracetamol levels in the PEG and Fattibase® suppositories were 103.7 ± 5.2% and 102.5 ± 6.5%, respectively. After 6 months, no significant changes were observed in the weight and morphology of the suppositories. However, the drug amount in the suppositories was slightly decreased in Fattibase® at 25°C (p < 0.05). The measured pH values of the extracted drug solutions were significantly increased at 6 months in both bases (p < 0.05).ConclusionTwo compounded paracetamol suppositories remained stable for 3 months at 4°C and 25°C. Three months could be assigned as the expiry date of compounded products.