Evaluation of Palm Oil-Based Paracetamol Suppositories by Differential Scanning Calorimetry

Purpose: To use differential scanning calorimetry (DSC) to predict the liquefaction time and dissolution profile of some commercial paracetamol suppositories as well as paracetamol suppositories formulated with palm oil base. Methods: The suppository base was prepared by mixing hydrogenated palm oil and palm kernel stearin in a ratio of 8:2. Three commercial paracetamol suppositories (A, B, and C) were purchased, while product D, paracetamol suppository was formulated with suppository base using the double casting method. In-vitro drug release from suppositories was determined using DSC and the effect of liquefaction on drug release was studied. The relationship between suppository melting and dissolution was analysed statistically. Results: The melting temperature of products A and B were 41.0 and 40.0 oC respectively, whereas those of products C and D were 35.9 and 33.1 oC, respectively. The liquefaction time of the suppositories were 61.4 (A), 54.2 (B), 9.0 (C) and 7.4 min (D). Less than 40 % paracetamol was released from products A and B in 2 h, while products C and D showed good dissolution with > 95 % drug release in 15 min. Statistical analysis using Pearson’s test indicates that the proportion of melt in the suppository base correlates well with drug release (p < 0.05). Conclusion: Paracetamol release from palm oil suppositories is rapid and correlates with melting of the base. DSC can be used to predict drug release in paracetamol suppository formulations.