Starch-silicon dioxide coprecipitate as superdisintegrant: formulation and evaluation of fast disintegrating tablets

The objective of the present investigation is to synthesize and characterize starch-silica coprecipitate and evaluate as tablet superdisintegrant. The starch-silica coprecipitate was synthesized by coprecipitation of silica on the surface of starch particles as reported by Rashid et al. The coprecipitate was characterized in terms of compressibility characteristics, Differential Scanning Calorimetry (DSC) and Fourier Transformed Infra Red Spectroscopy (FTIR). Fast dissolving tablets were then formulated by direct compression method using the different concentration of coprecipitate, crosscarmellose sodium (CCS) and crosspovidone (CP) as superdisintegrant. The tablets were evaluated for the disintegration time, hardness, friability, tensile strength, weight variation and in vitro release studies. The starch-silica coprecipitate showed better disintegration and compressibility characteristics as compared to the known superdisintegrants. FTIR indicated the absence of any chemical reaction between the two species (starch and silica) during the process of coprecipitation. DSC studies showed there is no interaction between the drug and coprecipitate. Hausner’s ratio & Carr’s index value of (1.17 and 14.7 respectively) of coprecipitate suggested excellent flowability. The coprecipitate was found to be effective at all the concentrations tested in the fast dissolving tablet formulation. Disintegration time (DT) of less than 30 seconds was observed in case of coprecipitate whereas higher DT values was observed with CCS and CP as superdisintegrants. Starch-silica coprecipitate can be utilized as a superdisintegrant in the pharmaceutical applications owing to better compressibility and release characteristics