The evaluation and comparison of various tablet disintegrants

Abstract

The aim of the tablet formulator is to formulate a tablet, which when ingested, disintegrates to give the same system or powder blend as before compression. The faster this disintegration can occur, the faster the absorption of the active ingredient, and thus the faster a physiological effect can be expected. There is no single mechanism of action for disintegrants, but rather a combination of mechanisms which causes disintegration, including water uptake (capillary action), swelling, gas production, deformation and particle repulsion.

Compacts of various pure disintegrants were prepared and evaluated in terms of their disintegration efficiency and their mechanism of action, including potato starch, sodium starch glycolate, Explotab®, Avicel® PH 200, Ac-Di-Sol® and Kollidon® CL. The compact hardness, disintegration time, water uptake and swelling of each pure disintegrant were evaluated at different compression forces. Order of disintegration time of the pure compacts seemed to be: Kollidon® CL ≈ SSG ≈ Potato starch < Explotab® <<Ac-Di-Sol® <<< Avicel®, for water uptake: SSG > Kollidon® CL >> Avicel® >>> Explotab® > Potato starch > Ac-Di-Sol®, and for swelling: SSG >> Avicel® ≈ Kollidon® CL ..>>Potato starch > Explotab® ≈ Ac-Di-Sol®. The best swelling and water uptake profiles were found for the super disintegrants, namely Kollidon® CL, sodium starch glycolate (Explotab®) and Ac-Di-Sol®. The super disintegrants are known to be more efficient because of their rate and extent of swelling, despite small concentrations needed in a formulation. Various factors affecting the efficiency of the disintegrants were used to conduct a fractional factorial design. Two super disintegrants (Explotab® and Ac-Di-Sol®) were formulated in different concentrations (0.5% and 1.0%) in a soluble (Tablettose®) and insoluble (Emcompress®) formulation, with different types (magnesium stearate and Pruv®) and concentrations (0.5% and 1.0%) of lubricant and tabletted at two different compression forces (setting 1 and 7). Results were statistically analysed and the main effects of each factor on the responses were calculated. Formulations with Ac-Di-Sol® as disintegrant showed better disintegration profiles in terms of disintegration time, swelling and water uptake, than the formulations with Explotab® as disintegrant. A concentration of 1.0% super disintegrant was more effective than 0.5%. The hydrophobic nature of magnesium stearate as lubricant in a formulation probably prevented liquid penetration and thus increased disintegration times, with 1.0% having a greater detrimental effect than 0.5%. Formulations with Pruv® as lubricant did not exhibit this disadvantages. The two compression forces used during tabletting did not seem to have any

significant effect on the efficiency of the disintegrants. The fractional factorial design made it possible to predict a formulation for optimum disintegration in tablets.