March 31, 2026
Distinguishing Silicone Oil Particles: Implications for Drug Products
Silicone oil is commonly applied to components involved in primary drug containment, primarily serving as a lubricant for elastomeric parts. For instance, silicone oil is commonly applied to rubber stoppers and plungers to facilitate machinability throughout the fill-finish process. Similarly, it is used on the inner surface of syringes to enable smooth and controlled movement of the piston during injection. However, silicone oil introduced into the primary container may migrate into the drug product, where it can appear as sub-visible particulate matter—an important critical quality attribute (CQA) of the final drug product.
John Rech
Technology Manager, Particle Testing, West Scientific Affairs