Why some tablets are dispersible?

Answer 1

Fast dispersible tablets disintegrate either rapidly in water, to form a stabilized suspension, or disperse instantaneously in the mouth to be swallowed without the aid of water. A direct compression method was used to prepare these two types of tablets containing coated ibuprofen as a high dosed model drug. The properties of the water dispersible tablet, such as porosity, hardness, disintegration time and increase in viscosity after dispersion, were investigated. The selected tablet formulation, containing 26% galactomannan and 5% crospovidone, disintegrates before the galactomannan starts to swell. These tablets disperse in water within 40 s and show a crushing strength of 95 N. To develop an orodispersible tablet, a rotatable central composite design was applied to predict the effects of the quantitative factors mannitol and crospovidone as well as compression force on the characteristics of the tablet. Special emphasis was paid to the development of a wetting test, replacing the normal disintegration method. An optimum tablet formulation, containing 34% mannitol and 13% crospovidone, provides a short wetting time of 17 s and a sufficient crushing strength of 40 N. In conclusion, fast dispersible tablets with acceptable hardness and desirable taste could be prepared within the optimum region.