Dissolution tests of acetaminophen filled into the gelatin capsules (SHIONOGI QUALICAPS, Japan) and hydroxypropylmethylcellulose (HPMC) capsules (SHIONOGI QUALICAPS, Japan) were performed after the cap-sules were stored under conditions of 30°C/60%RH for one year, 40°C/75%RH for 6 months, or 60°C for one week. The Japanese Pharmacopoeia 1st fluid, acetic acid buffer (pH4.0), Japanese Pharmacopoeia 2nd fluid and purified water were used as dissolution media. The dissolution profiles of the gelatin capsules changed significantly in comparison to those of the initial profiles after the capsules were stored at 40°C/75%RH for 6 months or 60°C for one week. On the other hand, no delay in dissolution was observed for the HPMC capsules.
Dissolution tests were additionally conduced using three commercially available HPMC capsules (SHIONOGI QUALICAPS, Japan ; CAPSUGEL, USA ; SHOGHUN, Korea), and the dissolution profiles of the HPMC capsules of SHIONOGI QUALICAPS were thus found to be independent of the dissolution medium, while the others showed different dissolution profiles depending on the dissolution medium.
