Ready-to-fill, i.e. sterile, prefillable glass syringes, are washed, siliconised, sterilised and packaged by the primary packaging manufacturer. They can then be filled by pharmaceutical companies without any further processing.These days the majority of prefillable syringes are made of glass, and the trend looks set to continue. The siliconisation of the syringe barrel is an extremely important aspect of the production of sterile, prefillable glass syringes because the functional interaction of the glass barrel siliconisation and the plunger stopper siliconisation is crucial to the efficiency of the entire system. Both inadequate and excessive siliconisation can cause problems in this connection. Bruno Reuter & Claudia Petersen at Gerresheimer Bünde explain how, with the use of modern technology, we can achieve an extremely uniform distribution of silicone oil in glass syringes with reduced quantities of silicone oil.