Application of some polymers in the physiocochemical design of tablet formulation

Polyethylene glycol 4000 did not apprecialbly affect the rate of drug release from tablets. The use of sodium alginate the a tablet binder showed variable effects on the rate of drug release from the tablet i.e. The incorporation of only 2.5% of sodium alginate caused enhancement in the release rate of the drug based on its action as disintegration inducer. On the other hand, the incorporation of 20, 35 and 50% of sodium alginate showed a pronounced retardation in the rate of drug release from the tablets. This retardation was more pronounced in acid than in alkaline media. Accordingly, sodium alginate could be favourably suggested as tablet binder when retarded gastric absorption is the therapeutic aim required. Carbopol 940 when used as a tablet binder in a concentration of 2.5%, showed a marked enhancement of the release rate of the drug. On the contrary, it exerted a remarkable retardation in the rate of drug release from the tablets when incorporated in the relatively large proportions of 20, 35 and 50%. This retardation was more pronounced in alkaline than in acid media. Accordingly, Carbopol 940 would be favourably suggested in the physiocohemical design of prolonged-release tablet formulations.