Dissolution of Extemporaneous Paracetamol Capsules

Aim: To investigate the dissolution characteristics of extemporaneously prepared capsules containing hypromellose and paracetamol tablets. Method: Capsules of varying sizes containing paracetamol (powdered tablets) with varying amounts of hypromellose (4–20% w/w) were extemporaneously prepared. Dissolution was investigated using a USP dissolution testing apparatus. Paracetamol dissolution was quantitated using UV absorption spectrophotometry. The impact of hypromellose content, tablet excipients, capsule size, content weight and mixing methods were investigated. Results: Over a 4‐hour period, paracetamol dissolution decreased with increasing hypromellose content. Paracetamol dissolution was 100% from capsules containing 4% hypromellose and 52 ± 3% from capsules containing 20% hypromellose. Reformulated tablets with different formulations resulted in different dissolution rates. The dissolution rate was faster from small capsules and slower from capsules with a lower content weight. The method used to mix the powders also had a significant effect on the dissolution rate. Conclusion: Modified‐release delivery systems can be extemporaneously prepared from reformulated tablets using hypromellose. Hypromellose content, tablet excipients, capsule size, content weight and mixing methods have an impact on the dissolution rate. J Pharm Pract Res 2004; 34: 276–81.