Although the standards for the quality of rubber closures on injectable glass vials were specified in USP 24 in the U.S. and BP 2001 in the U.K., no such guidelines for quality control exist in Japan. In the present study, we investigated the quality of rubber closures on glass vials of frequently-used anti-biotic and anti-viral injections in our hospital, according to the quality control method of rubber closures for aqueous infusion that was standardized in JP14. Sufficiently washed rubber closures were immersed in distilled water, and test solutions were prepared after gently shaking them for 5 min or heating them at 121°C under high-pressure steam for 60 min. The optic transmittance in the resultant solutions was measured at 430nm and 650nm, and the findings were compared with those for the standard values in JP14 for rubber closures on aqueous infusions. Of 23 different rubber closures tested, only one showed a lower transmittance at 430nm when the solution was prepared by gentle shaking. Under the condition of heating with high-pressure steam, 15 products did not reach the criteria at both wavelengths, 3 did not meet the standards set at either of the wavelengths, but 5 had no qualitative problems. We also checked the materials stuffed in 0. 45μm membranes after filtration with an injection by microscopic observations using scanning electron microscopy and by an element analysis with an X-ray energy dispersive microanalyzer. A number of micro-particles were observed and they were found to be composed of silicon, aluminium and titanium.
These results indicate that the quality of rubber closures of injectable glass vials varies among products. Therefore, the standards and guidelines for the quality control of rubber closures of injectable glass vials should be established in JP.
