AUTOMATED-METHOD FOR DETERMINING INSTRON RESIDUAL SEAL FORCE OF GLASSVIAL RUBBER CLOSURE SYSTEMS

Instron Residual Seal Force (IRSF) of glass vial rubber closure system s was determined using an Instron 4501 Materials Testing System. Compu ter programs were written to process raw data and calculate IRSF value s. Preliminary experiments indicated both the appearance of the stress -deformation curves and precision of the derived IRSF values were depe ndent on the internal dimensions and top surface geometry of the cap a nvil. Therefore, a series of five cap anvils varying in shape and dime nsions were machined to optimize performance and precision. Vials capp ed with West 4416150 PURCOAT(R) button closures or Helvoet compound 62 07 lyophilization closures were tested with each cap anvil. Cap anvils with spherical top surfaces and narrow internal dimensions produced m ore precise results and more uniform stress-deformation curves than ca p anvils with flat top surfaces and wider internal dimensions.