Effect of storage at specified temperature and humidity on properties of three directly compressible tablet formulations.

Direct compression tablets containing sodium starch glycolate, an alginate derivative, or povidone as a disintegrant, magnesium stearate as a lubricant, amaranth as a tracer, and dibasic calcium phosphate dihydrate as the matrix were stored for 30 days at 23 degrees and 75% relative humidity (R.H.), 45 degrees and 75% R.H., and 65 degrees and 40% R.H. Samples were evaluated after 0, 10, 20, and 30 days for size, hardness, and dissolution characteristics. Although no significant changes in the dimensions or hardness of the three tablet formulations, prepared at three different compaction pressures, were observed, the dissolution efficiency of the systems showed significant changes, some systems dissolving more rapidly and some more slowly after storage. In some cases, the changes were so substantial as to indicate the possibility of significant changes of the bioavailability of drugs formulated in such systems. The relevance of this work to the problem of evaluating aging effects on the physical properties of tablets is discussed.