Methods for the assessment of the stability of tablet disintegrants

To allow assessment of the long-term stability of tablet disintegrants, two mechanisms for their functionality (i.e., water uptake and swelling force generation) were monitored. Three disintegrants, alginic acid, sodium starch glycolate, and crospovidone, were used to establish the methodology. The water uptake and swelling force methodologies developed were reproducible, thus allowing for the evaluation of the effect of time, temperature, and humidity on these properties of disintegrants. The data obtained suggest that the process of water uptake and swelling force generation was essentially a two-step process. Initially, water entered the pore space in the powder bed; there was a definitive lag time before a swelling force was generated. In the stability evaluation of alginic acid and sodium starch glycolate, samples were stored for 1-year. Above 30 degrees C and 75% relative humidity, the swelling force performance of alginic acid was markedly affected. Changes seen with sodium starch glycolate were much less marked.