YY/T 0681.17-2019Test methods for sterile medical device package - Part 17: Testing the microbial barrier performance of porous package materials using aerosol filtration method (English PDF)

1 Scope

This Part of YY/T 0681 specifies the determination of the aerosol filtration performance using aerosol that generates particles with a diameter of 1.0 µm, and the evaluation of the filtration efficiency of the material using two particle counters.

This Part of YY/T 0681 is applicable to air permeable materials used for the packaging of terminally sterilized medical devices.

This Part of YY/T 0681 does not apply to materials with Bendtsen air permeability1) over 4,000 mL/min.

2 Normative References

The following documents are indispensable to the application of this document. In terms of references with a specified date, only versions with a specified date are applicable to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document.

GB/T 19633.1-2015 Packaging for Terminally Sterilized Medical Devices - Part 1: Requirements for Materials, Sterile Barrier Systems and Packaging Systems (ISO 11607-1:2006, IDT)

3 Terms and Definitions

The following terms and definitions are applicable to this document.

4 Symbols

The following symbols are applicable to this

document. CF: the average particle count of filtrate

aerosols. CC: the average particle count of challenge aerosols.

R: the percentage of the number of filtrate aerosol particles in the number of challenge aerosol particles. RM: the maximum calculated value of R.

P1: the pressure difference generated before and after the specimen by the calibrated air flow through the specimen required by the particle

counter. P: the pressure difference before and after the

specimen. F: the air flow passing through the specimen.

F1: the calibrated air flow through the specimen required by the particle counter when measuring the filtrate aerosol. FM: the air flow, at which the maximum penetration occurs.

5 Overview of Test Methods

5.1 Place the air permeable packaging material specimen in the sample holder, so that a filter is formed between the challenge aerosol and the filtrate aerosol. On the challenge side of the sample holder, the particle aerosol is on the surface of the specimen. Let the air flow pass through the specimen. Use a laser particle counter to monitor the particle concentrations of the challenge aerosol and the filtrate aerosol. Within a certain flow range, measure the particle concentration, so as to determine the penetration percentage within the flow range. After data processing, obtain the maximum penetration point.

5.2 This test uses polystyrene latex (PSL) particle aerosol with a geometric mean particle size of 1.0 µm and a standard deviation of less than 0.05 µm. Use two particle counters to simultaneously, respectively and continuously count the challenge aerosols and the filtrate hPa ~ 5 hPa and an accuracy of 0.005 hPa, which is used to monitor the pressure difference on both sides of the sample.

7 Instruments

7.6 Pressure regulator: a precision pressure regulator that can provide 1.0 standard liter of gas per minute when the pressure reaches 0.3 MPa.

7.7 Ultra-efficient air filter: used to remove particles in the ambient air.

7.8 O-shaped ring: nitrile rubber, which forms a seal between the test challenge side and the filtration side.

8 Materials

8.3 Concentrated suspension of 1 µm PSL particles (such as: Duke Scientific 3K1000, 5100A and G0100).

8.5 Air permeable packaging materials to be tested

8.2 Tween 20 or sodium dodecyl sulfate (SDS)

9 Instrument Preparation

11 Test Procedures

11.2 Set up the particle counter to continuously record the particle count and pressure data using the 0.7 µm and 1.0 µm channel data.

11.3 Test the distilled water / surfactant to ensure that its cleanliness complies with 9.2.1.

11.4 Prepare a PSL suspension with a suitable concentration and verify that the difference in particle counts is within 3% as described in 9.2.2.3.

11.5 Cut the sample and put the sample into the sample holder as described in 10.

11.7 Turn on the aerosol flow and allow the challenge count to stabilize.

11.8 Close the Venturi needle valve to make the inlet pressure reach 0.3 MPa. Open the Venturi needle valve, until the pressure difference across both sides of the sample reaches 2 hPa, stabilize for 1 min; when 50 filtrate particles are detected (or at least 45 s), start counting the challenge particles and the filtrate particles, and record the pressure difference, the number of challenge particles and the number of filtrate particles.

11.9 Adjust the Venturi needle valve (or reduce the Venturi tube / purge pressure to zero) to reduce the pressure difference on both sides of the sample by 1/2; stabilize for 2 min; wait until 50 filtrate particles are detected (or at least 45 s), start counting the challenge particles and the filtrate particles; record the pressure difference, the number of challenge particles and the number of filtrate particles. Continue to reduce the pressure difference on both sides of the sample by 1/2, until the maximum penetration is detected (or the needle valve is closed, or the Venturi tube / purge pressure is zero). If the maximum penetration value has not been reached, record the pressure difference (P1), at which, the needle valve is closed (or the Venturi tube / purge pressure is zero) before switching to the low flow range.

11.10 If needed, set the Venturi tube / purge pressure to zero and select the low flow range.

11.11 Increase the pressure of the Venturi tube / purging air flow, until the pressure difference on both sides of the sample reaches the next test point; stabilize for 2 min; when 50 filtrate particles are detected (or at least 45 s), start counting the challenge particles and the filtrate particles; record the pressure difference, the number of challenge particles and the number of filtrate particles. Continue to reduce the pressure difference by 1/2, and collect data, until the average count result within 60 s is less than 25, or the pressure difference is no longer stable.

11.12 Use the challenge counts accumulated over the time period up to 100 filtrate counts for data analysis; correct the test results of the low flow range.

11.13 The penetration rate at a given pressure difference is equal to the average number of filtrate particles divided by the corresponding average number of challenge particles. […]