Purpose: Titanium dioxide (TiO2) is the most widely used white pigment in pharmaceutical/Nutraceutical coating formulations. It has high brightness and a very high refractive index. Apart from producing a white colour in liquids, paste or as coating on solids, TiO2 is also an effective opacifier, making substances more opaque. However there has been information that the white pigment titanium dioxide (TiO2) is a potential carcinogen. Hence many pharmaceutical companies are avoiding use of titanium di oxide in their pharmaceutical and nutraceutical products .Calcium carbonate is an alternative opacifier which is non-toxic, economical and safe for consumption. The objective of this study is to develop an optimized Ready-mix formulation containing Calcium Carbonate as an alternative opacifier instead of Titanium Di-Oxide.
Methods: Instanute IR, a ready formulated coating system comprising of calcium carbonate as opacifier, was used in this study with DM water for coating suspension preparation. An experimental plan with varied concentration of calcium carbonate (15% and 25%), were used. Coating suspension was prepared with 15% solids content. Viscosities of suspensions were measured using a Brookfield viscometer. Coating trials were executed in a conventional coating pan using yellow core tablets till 5% weight gain . The critical coating process parameters i.e product bed temperature, spray rate , pan rpm and % weight gain were optimized . Instanute IR film coating opacity was determined by measuring the contrast ratio of the coatings on opacity chart using a Data color® 500 machine.
Results: Coating was successfully done using Instanute IR coatings having Calcium Carbonate as a opacifier .The core tablets achieved good covering properties at 3% weight gain of Instanute IR coating (Ref. attached JPG file). Opacity of Instanute IR film coatings containing calcium carbonate were determined by measuring the contrast ratio using Datacolor Instrument .The contrast ratio was found comparable with the film coating formulations containing Titanium dioxide .
Conclusion: The opacity of Instanute IR coatings containing calcium carbonate was assessed and found good. Instanute IR formulations containing calcium carbonate provide a good alternative to typical coatings containing titanium di oxide for Nutraceuticals exhibiting good hiding and coloring properties .