Preparation and characterization of starch-metal silicate Co-precipitates--evaluation as tablet superdisintegrant

Starch is a potential biomaterial used for various pharmaceutical applications because of its unique physicochemical and functional characteristics. A number of modification techniques, such as physical, chemical, enzymatic and genetic or a combination of any of these methods have been reported with the aim of enhancing the positive attributes and eliminating the shortcomings of the native starches.

The present studies deal with the development of co-precipitates of corn starch with different silicates (Mg, Ca, Al) with an aim of using it as a tablet superdisintegrant. Co-precipitates of starch with different silicates were prepared and FTIR-ATR, XRD and SEM techniques were used for the characterization of conjugates.

The conjugate were analyzed for various powder evaluation test like angle of repose, bulk density, tapped density, Hausner's ratio, Carr's index, swelling index and effective pore radius.

The prepared co-precipitates were found to possess good powder flow properties. The swelling and effective pore radius of all co-precipitates (SMgC, SAlC and SCaC) was found in the range between 30-100% and 15.89-21.71 μm respectively. Different ratios of the prepared co-precipitates were used to formulate fast disintegrating tablets. Fast disintegrated tablets formulated using starch silicate conjugates as superdisintegrant were evaluated for diameter, thickness, hardness, friability, tensile strength, in vitro tablet disintegration, water absorption ratio, wetting time and in vitro dissolution studies. The effective pore radius and swelling of the co-precipitates were correlated with the in vitro disintegration, water absorption ratio and wetting time of the tablets.

It was concluded that silicated co-precipitates of starch could be used as superdisintegrants in pharmaceutical tablet formulations.