Impact of Formulation and Processing Parameters on Silicone Extraction from Cyclic Olefin Copolymer (COC) Syringes

The effect of various formulation and process parameters on the extraction of silicone from siliconized cyclic olefin copolymer (COC) syringes is reported. The impact of proprietary silicone curing process on COC syringe barrels was evaluated with respect to the rate and extent of silicone extraction. Similarly, the impact of formulation parameters such as pH, ionic species, and cosolvents on silicone extraction was also evaluated. The rate and extent of silicone extraction into contact solutions was inversely related to the degree of completion of the silicone curing process. The rate and extent of silicone extraction in solution were highest upon exposure to extreme pH solutions. The silicone extraction data indicate that the silicone curing process and formulation parameters have a profound effect on the rate and extent of silicone extraction into solutions.

Silicone oils are used in medical syringes to provide lubrication. Prefilled medical syringes contain solutions into which silicone oil components may migrate. This study examined the degree to which silicone components migrated into different solution matrices. The impact of different levels of proprietary silicone curing processes on the migration of silicone components in contact solutions was also examined. This study also examined the impact of various formulation parameters (pHionic strength and cosolvents) on the degree to which silicone components migrated into solutions. Solution pH had the greatest effect on silicone migration with higher levels of silicone measured in solutions at the pH extremes. Curing of the silicone (reaction of the silicone with the syringe materials) also had significant impact. High curing levels resulted in less silicone migrating into solution as compared to levels seen with syringes with low curing levels. Thus it was demonstrated that both the nature of the solution stored in the syringe and the degree of silicone curing on the syringe barrel had substantial impact on the amount of silicone that migrated from the syringe components into the solution contained within the syringe.