Method for testing sliding frictional response of lubricious thin films used in plastic medical syringes

Abstract

Lubricious thin films are used in plastic medical syringes in order to reduce the frictional forces between the syringe barrel and the rubber plunger. Polydimethylsiloxane (PDMS) liquid films are the current accepted technology for reducing the friction forces in plastic medical syringes. However, major issues with these PDMS films exist, including interactions of the film with the stored injectable drugs and variations in the frictional response as the syringes are aged over time. A new silicon based, lubricious octamethylcyclotetrasiloxane (L-OMCTS) thin film solid lubricant has been developed as a replacement for PDMS that provides acceptable and stable frictional responses without interacting with injectable drugs. A novel test method has been developed that can be used to successfully characterise the sliding frictional response of the L-OMCTS thin films at the syringe barrel and plunger interface. This test method will be used to provide future insight into how the frictional response of the L-OMCTS thin films is affected by various system parameters. This paper will mainly discuss the design of this new test method and provide some preliminary frictional response data.