Formulation and Evaluation of Moisture Protective Tablet Compression Coat Using Natural Polymers

This study aims to formulate and evaluate moisture protective coat for tablets using natural polymers of Fenugreek seeds and okra fruits in different concentrations compared with synthetic moisture protective coat. Ethanolic extracts of fenugreek and okra were treated with acetone as solvent for isolation of the mucilage, which is then dried and powders obtained identified and tested for polysaccharides using Molisch's reagent, Barofoead, KOH, Fehling reagent. The physicochemical tests including pH, viscosity, moisture content, percentage yield and swelling index were also carried out. Two formulations of 150 mg Silica gel tablets weighing 300mg and 500mg using PVP, magnesium stearate and Microcrystalline cellulose (MCC) as excipients were prepared and the powder mixture of flow ability was evaluated by measuring Carr's index, Hausener ratio and Angle of repose. The compressed tablets were evaluated according to USP monograph by testing the physical test of both tablets. Two coating materials were prepared and evaluated using natural polymers in different concentration 5%w/w and 10%w/w. The coated tablets with natural and synthetic polymers were compared by observing weight and moisture change of tablets pre and after stability study for 2 weeks in stress conditions at temperature (500 C) and RH 75 %. All the identification tests were positive indicating the presence of polysaccharides. Also, the physicochemical parameters tested were within the acceptable limits. Both fenugreek and okra mucilage's as polymers in low concentration 5%w/w revealed much better results regardless of weight of tablets. Coat defects were observed in tablets coated with 10%w/w of the polymers. The standard film coating polymer showed better moisture protection as moisture content about 4%. coating materials were successfully prepared and evaluated as moisture protective coat of silica gel tablets. Optimum coating formulations were found at 5%w/w concentration for mucilage's of both fenugreek and okra.