Influence of avicel PH-301 on the compressibility of alpha-methyldopa and phenobarbitone in direct compression

The aim of this work was to investigate the compressibility behavior of alp ha-methyldopa and phenobarbitone using a Korsch EK0 instrumented eccentric tablet machine, with force-time and force-displacement curves constructed a nd applied to calculate different compressional values to study the compres sional behavior. The results of this work revealed a difference in compress ibility behavior between the two drugs during the compressional process. al pha-Methyldopa gave an abnormal compressional curve with high friction in t he pre- and postcompressional phases. A. residual force could be seen on th e lower punch. Furthermore, capping and sticking were observed visually dur ing tablet pressing, indicating poor compressibility behavior. In. the case of phenobarbitone, no friction was observed in the precompressional phase, bur there was higher friction in the postcompressional phase, especially i n the ejection phase. The compressibility of the drugs was improved by the addition of Avicel PH-301 and magnesium stearate.