Effect of humidity on the disintegrant property of alpha-cellulose.

A study has been carried out to investigate the effect of humidity on the disintegrant property of alpha-cellulose in paracetamol tablets. The disintegrant alpha-cellulose or maize starch (for comparative studies) was incorporated intragranularly or extragranularly. The tablets were prepared by a wet granulation technique and then exposed to relative humidities (RH) 1%, 78% and 100% at an ambient temperature of 28 to 30 degrees C for various time intervals up to 2 weeks. They were evaluated for disintegration time, hardness and moisture uptake. Tablets stored under RH% and 78% disintegrated within 15 minutes while those containing alpha-cellulose stored at RH 100% for a period > or = 24 h failed to disintegrate within 60 minutes. The time taken for this conversion from disintegrating to non-disintegrating tablets varied with disintegrant concentrations and its mode of incorporation. Tablets containing maize starch did not display this moisture effect. The observation is thought to relate to the gelling of the alpha-cellulose particles upon moisture sorption. Thus, high relative humidities impair the disintegrant property of alpha-cellulose, which underlines the need to prevent such tablets from moisture.