PREFILLED SYRINGE AND METHOD OF PREPARING A PREFILLED SYRINGE

A method of preparing a prefilled syringe (1), comprises (i) obtaining a syringe barrel (11) having an open end (111) and a tip (112) with an orifice (113) essentially opposite to the open end (111), and a needle adaptor cap (12) assembled on the tip (112) of the syringe barrel, wherein the needle adaptor cap (12) has a rubber element (121) tightly sealing the orifice (113) of the tip (112) of the syringe barrel (11) and the syringe barrel (11) together with the needle adaptor cap (12) assembled on the tip (112) of the syringe barrel (11) is sterilized by a first sterilizing comprising a main step of exposing the syringe barrel (11) together with the needle adaptor cap (12) assembled on the tip (112) of the syringe barrel (11) to ethylene oxide for about 5 hours to about 60 hours at a relative humidity of about 40% to about 100% and at a temperature of about 30°C to about 60°C; (ii) filling a drug substance (14) through the open end (111) of the syringe barrel (11) into an interior of the syringe barrel; (iii) sealing the interior of the syringe barrel (11) by advancing a rubber stopper (13) through the open end (111) of the syringe barrel (11); (iv) packaging the syringe barrel (11) together with the rubber stopper (13) sealing the interior of the syringe barrel (11) and the needle adaptor cap (12) assembled on the tip (112) of the syringe barrel (11); and (v) second external surface sterilizing the packaged syringe barrel (11) together with the rubber stopper (13) sealing the interior of the syringe barrel (11) and the needle adaptor cap (12) assembled on the tip (112) of the syringe barrel (11). The rubber element (121) of the needle adaptor cap (12) and the rubber stopper (13) are made of a rubber material having a comparably low oxygen transmission rate such as, at 1 atmosphere, of not more than 64 cubic centimeter per square meter and day. The second external surface sterilizing comprises a main step of exposing the packaged syringe barrel (11) together with the rubber stopper (13) sealing the interior of the syringe barrel (11) and the needle adaptor cap (12) assembled on the tip (112) of the syringe barrel (11) to ethylene oxide for about 3 hours to about 30 hours at a relative humidity of about 40% to about 100% and at a temperature of about 25°C to about 45°C. At least one of the duration, the relative humidity and the temperature of the second external surface sterilizing is essentially 28 lower than the respective duration, relative humidity or