| This research was designed to predict shelf life of packaged pharmaceutical tablets by using dissolution as a function of moisture content and storage time. Shelf life was predicted by the amount of time required for the moisture content of the pharmaceutical product to increase until it reached equilibrium (permeation time) plus the time that the product could tolerate that storage condition (exposure time) in an open dish study. Permeation time can be calculated by using information from a sorption isotherm, WVTR and other parameters, including product dry weight, storage conditions, initial and critical moisture content.; In this study, prednisone, a moisture sensitive uncoated tablet, was stored in an open dish at 75%RH at 25°, 30° and 40°C to determine exposure time. To prove the validity of the calculation, the actual permeation time was determined by measuring the moisture content of prednisone packaged in PVC and PVC/0.6 mil Aclar blisters at certain intervals. The calculation provided an error of less than 10%. Therefore, this calculation is useful to select the packaging material that provides enough moisture barrier to the products for the stability test. The actual dissolution shelf life was determined by using as critical point a 10% reduction in dissolution. The shelf life predicted and the actual shelf life were compared. Predicted shelf life was from 8 to 44 percent less than the experimental result. |
