Evaluation of Some Anionic Exchange Resins as Potential Tablet Disintegrants

Purpose: To determine the potential of some anionic exchange resins as tablet disintegrants.
Methods: Dowex1® x2, x4 and x8 resins (crosslinked copolymers of styrene and divinylbenzene with quaternary methyl amine functionality) were evaluated as disintegrant for dibasic calcium phosphate dihydrate tablets. The best resin providing the fastest disintegration and highest hardness of obtained tablets was selected for further investigation. The effect of resin concentration and compression force on the properties of tablets using the selected resin was investigated. In addition, the disintegrant efficacy of the selected resin in the tablet formulations containing either a basic drug, e.g., dextromethorphan hydrobromide (DMP), or an acidic drug, e.g., diclofenac sodium (DCN), was determined in comparison with sodium starch glycolate (SSG).
Results: Dowex1®x2 resin exhibited the fastest disintegration (6.0 s) and the highest hardness (103.6 N) of obtained tablets. These disintegrating and tablet properties depended upon the resin concentration and compression force. For DMP, the resin provided faster disintegration and drug release (8.0 s and 100.4 % at 10 min) as compared with SSG (16.2 s and 98.9 % at 30 min). In contrast, the resin caused the depleted release of DCN (61.6 % at 120 min) in spite of providing the faster tablet disintegration (10.0 s) than SSG (15.5 s) due to the ionic binding of the drug and resin.
Conclusion: The Dowex1®x2 resin was shown to be a potential disintegrant for the tablets of basic drugs.

Keywords
Anionic exchange resin; Disintegrant; Dextromethorphan hydrobromide; Diclofenac sodium; Calcium phosphate