Coloration and Stability of the Controlled-Release Mesalazine Tablets Repackaged by the One-Dose Packaging Machine for Dispensing

Recently, automatic tablet counting and packaging machines have come to be widely used for the one-dose packaging of tablets and capsules. However, coloration, i.e. changes in color, of such tablets repackaged by one-dose packaging machins for dispensing has been frequently observed in several kinds of tablets due to the light, humidity and temperature in the room. In this report, the changes observed over time in the controlled-release mesalazine product, Pentasa® tablets, repackaged with polyethylene-laminated cellophane and glassine films for the one-dose packaging was studied. The repackaged tablets changed color within a week at room conditions (22-25°C, 50-70% RH) under a 350 lux fluorescent white-1 amp ex posure for 12 h per day or in darkness. However, no coloration was observed for at least four weeks in a refrigerator (4°C, 20% RH) in dark ness. The weight of the repackaged tablets increased by about 1% at room conditions within a week, while no such weight increase in the tablets was observed while the tablets were kept in a refrigerator. No changes in the amounts of mesalazine and its degradates, gentigic acid and p-aminophenol, in the tablets were observed and the dissolution properties of mesalazine from the tablets also remained unchanged during the experimental period. Based on these findings, we conclude that the one-dose packaging of Pentasa® tablets is not a suitable procedure since it results in the absorption of moisture and changes in color.