The preparation of anticancer drugs necessitates careful work because it can involve the handling of hazardous drugs. In actual clinical settings, liquid leakage can occur if the same rubber stopper is penetrated with injection needles multiple times; special attention should be paid to the fact that the first penetration mark can serve as a site of leakage to increase risk.
Hence, we conducted a confirmatory study to detect air leakage, which can be detected with greater sensitivity than liquid leakage, using a number of methods of penetration with a focus on the viscoelasticity of rubber stoppers.
In the second penetration, when the bevel was oriented perpendicularly to the first penetration (AB method), a leakage rate of 100％ (30/30) was obtained with an 18 G regular-bevel needle penetrating the rubber stopper at a short depth of 0.5 mm from the first penetration mark. When the bevel orientation was changed under otherwise the same conditions (CB method), the leakage rate decreased to 37％ (11/30). When the bevel orientation was completely aligned to the orientation of the first penetration (BB method), the leakage rate further decreased to 0％ (0/30). Another important factor was the depth of penetration; under all conditions examined, lower leakage rates were obtained with a 1.0 mm depth than with 0.5 mm.
As a result, in clinical settings involving two occurrences of penetration, two distinct cases were revealed depending on needle bevel positioning: spills and other forms of leakage prevented by the viscoelasticity of the rubber stopper and those promoted by the same.
