Effect of tablet solubility and hygroscopicity on disintegrant efficiency in direct compression tablets in terms of dissolution.

The effect of tablet composite solubility and hygroscopicity on the dissolution efficiency of three "super disintegrants", sodium starch glycolate, crospovidone, and croscarmellose sodium, was investigated. Lactose, dicalcium phosphate dihydrate, and sorbitol, alone or in combination, provided varying degrees of solubility and hygroscopicity to the direct compression tablet formulations. To monitor in vitro dissolution, 1% p-aminobenzoic acid was added to the formulation as a tracer. The results indicate that hygroscopic ingredients decrease the effectiveness of super disintegrants in promoting in vitro dissolution. The greater the overall hygroscopicity of the tablet formulation, the larger the decrease in the efficiency of the super disintegrant. Composite tablet solubility did not influence the effectiveness of the super disintegrants. Super disintegrants that complied with the same compendial specifications, but were manufactured by different companies, behaved similarly in promoting tablet dissolution.