High Viscosity

The customer developed a high viscosity drug (>1,500 cP) that will be packaged in a pre-filled syringe and used in an auto-injector.  The drug may be terminally sterilized with gamma irradiation.  Due to the high injection forces, it is not possible to use a glass syringe due to the risk of breakage.   Moreover, borosilicate glass discolors when subjected to gamma irradiation.

• SiO2 developed a custom 2.25 mL staked needle syringe composed for use in an auto-injector that can withstand the injection forces of the high viscosity drugs.
• SiO2 worked with the customer’s autoinjector provider to conduct a stress analysis to determine the high stress areas of the design based on the autoinjector interface to the syringe. The design was optimized based on the analysis.  SiO2 conducted a mold flow analysis of the proposed design and developed a mold to produce the syringe.
• SiO2 developed the product and scaled up an automated manufacturing line. The syringe incorporated SiO2’s barrier and lubricity coating technology. SiO2 developed the internal diameter of the syringe based on a standard plunger to withstand the high injection forces expected and not leak past the plunger. 
• Verification testing showed that the syringe can withstand a force of 320N (an internal pressure of 800 psi, 5,535 kPa) – this exceeds the force requirements for the high viscosity drug.