Characterization of Hydroxypropyl Tapioca Starch and its Pregelatinized Starch as Tablet Disintegrants

Hydroxypropyl tapioca starches (HPTS) and pregelatinized hydroxypropyl tapioca starches (PG‐HPTS) with different molar substitutions are characterized as tablet disintegrants in comparison with native tapioca starch (NTS). Powder XRD and polarized light microscopy indicates that HPTS is A‐type crystalline starch similar to NTS, whereas PG‐HPTS is amorphous. Compared to HPTS, an increase in swelling capacity with higher degree of hydroxypropyl substitution is observed with PG‐HPTS. All tablets containing NTS, HPTS, and their pregelatinized starches at 5% and 10% show fast disintegration within 8 min. Interestingly, the tablets with disintegration times of less than 30 s are obtained when NTS and HPTS are used. The tablets containing PG‐HPTS with higher degree of hydroxypropyl substitution show longer disintegration time and more retarded drug dissolution when compared to those with non‐pregelatinized starches. This might be attributed to higher water sorption and subsequent swollen gel formation of PG‐HPTS. The effect of hydroxypropylation on tablet disintegration and dissolution is clearly observed with PG‐HPTS. The results revealed that the functionality of PG‐HPTS is dependent on the degree of hydroxypropyl substitution, but less dependence is observed with HPTS. In conclusion, HPTS and PG‐HPTS with different molar substitutions could be used as disintegrants in tablet formulation. Hydroxypropyl tapioca starch (HPTS) and pregelatinized hydroxypropyl tapioca starch (PG‐HPTS) could be used as a disintegrant in tablet formulations. The PG‐HPTS with higher molar substitution has higher swelling and rapid gel formation, thus prolonging disintegration time and retarding drug dissolution. The functionality of PG‐HPTS is dependent on the degree of hydroxypropyl substitution, but less dependence is observed with HPTS.