INDEXES OF TABLETTING PERFORMANCE FOR ACRYLIC RESIN POLYMERS WITH PLASTIC AND BRITTLE DRUGS

The indices of tableting performance were used to investigate the comp action properties of two methacrylate ester copolymers (Eudragit(R) RS PM and RL PM) and three methacrylic acid copolymers (Eudragit(R) S 10 0, L 100, and L 100-55). These polymers were designed to be incorporat ed directly into solid dosage forms for controlled-release purposes. T he polymers were combined in the dry state with either sodium sulfathi azole (a brittle drug) or theophylline (a plastic drug) at concentrati ons ranging from 0 to 100% polymer. All powders were blended for 15 mi nutes and compacts measuring 1 inch square and weighing 5 g each were made using a die that decompressed triaxially and a Carver(R) press eq uipped with a strain gauge. Solid fractions were kept constant at 0.81 . Two of the tableting indices, the bonding index (BI) and brittle fra cture index (BFI), were studied for all mixtures. The BFI of the sulfo namide (0.49) was nearly three times greater than the BFI for theophyl line(0.17) The three methacrylic acid copolymers had high BFI values r anging from 0.99 to 1.60, demonstrating the brittle characteristics of these polymers. The BFI decreased with increasing drug content in all cases. Of the five polymers, the BI was greatest for Eudragit(R) L 10 0-55 with both drugs, especially at the 20% drug concentration, follow ed by Eudragits L 100 and S 100. These three resins were prepared by a spray-drying process. The strongest interactions (positive deviations for the BFI; negative deviations for indentation hardness and BI) of either drug with the polymers were always seen with the spray-dried ma terials. Low bonding indices were obtained for both of the methacrylat e ester copolymers. However, all mixtures of both drug with these mill ed polymers (RL PM and RS PM) formed successful tablets.