C-Flex Biopharmaceutical Tubing
X-Ray Sterilization of Single-Use Bioprocess Equipment

Part II - Representative Qualification Data

X-Ray Sterilization of Single-Use Bioprocess Equipment

Part II - Representative Qualification Data

BPSA and several industry partners, including Saint-Gobain Life Sciences, participated in the creation of this white paper.  Participants ranged from Author and Data Contributor to Contributor and Reviewer.  Saint-Gobain's own Abbie Wilson participated as Author and Data Contributor.  This white paper compares the use of gamma irradiation to X-Ray irradiation for sterilization of single-use components and materials.  The following are excerpts from the white paper that focus on Saint-Gobain C-Flex® 374 and Sani-Tech® Ultra-C Tubing as part of the comparison of sterilization methods. 

Scroll to the bottom to download the full white paper.

3. Physical and Functional Component-Specific 

3.5 Tubing

C-Flex® 374 Tubing

Functional and physical property testing were performed on C-Flex® 374 tubing and slab3 material (all TPE) following gamma and X-ray irradiation in the 50±5 kGy dose range.

3 Slab refers to a thick, flat sheet of the same material that may be more appropriate for some types of testing

Burst Pressure TestingC-Flex® 374 Average Burst Pressure

Burst pressure testing was performed on 10 tubing samples of C-Flex® 374 following gamma or X-ray irradiation (Figure 7). The maximum pressure reached at the point of failure was recorded for each sample. The results demonstrate equivalence between samples that were gamma and X-ray irradiated. It is typical for burst pressure to decrease follow irradiation of C-Flex® 374.

Material Bend RadiusC-Flex® 374 Average Material Bend Radius

Bend radius or kink resistance testing determines how much a tube can be bent before kinking, the point at which liquid would theoretically no longer be able to flow through the tube. Material Bend Radius testing was performed on 10 tubing samples of C-Flex® 374 tubing after gamma and X-ray irradiation. The results demonstrate equivalence between samples that were gamma and X-ray irradiated. It is typical for C-Flex® 374 to increase in bend radius following irradiation. The Figure 8 displays the relative average of the ten samples from each testing group. 


Sani-Tech® Ultra-C Tubing

Functional and physical property testing has been performed on Sani-Tech® Ultra-C tubing and slab material (all pt-cured silicone) following gamma and X-ray irradiation in the 50±5 kGy dose range.

Burst Pressure Testing Sani-Tech-Ultra-C average burst pressure

Burst Pressure testing was performed on 10 tubing samples of Sani-Tech® Ultra-C after gamma and X-ray irradiation. The maximum pressure reached at the point of failure was recorded for each sample. The results demonstrate equivalence between samples that were gamma and X-ray irradiated. It is typical for burst pressure to increase follow irradiation of Sani-Tech® Ultra-C due to cross-linking. The Figure 9 displays the relative average of the ten samples from each testing group.

Material Bend Radius Sani-Tech-Ultra-C average material bend radius

Material Bend Radius testing was performed on 10 tubing samples of Sani-Tech® Ultra-C tubing after gamma and X-ray irradiation. The results demonstrate equivalence between samples that were gamma and X-ray irradiated. It is typical for Sani-Tech® Ultra-C to increase in bend radius following irradiation. Figure 10 displays the relative average of the ten samples from each testing group. 
 

 

C-Flex® 374 Tubing

5. Material Assessments

C-Flex® 374

Opacity and yellowness were measured on C-Flex® 374 following gamma and X-ray irradiation and compared to a control. The yellowness value of the tubing that was gamma irradiated was higher than the tubing that was X-ray irradiated as seen in the table below. A visual inspection was performed and there was little to no difference between the gamma and X-ray sample sets.

C-Flex® 374 Yellowness Index
(Average of 10)
Standard Deviation
(Sample set of 10)
Opacity
(Average of 10)
Standard Deviation
(Sample set of 10)
Control 2.15 0.20 20.16% 0.52
Gamma 3.89 0.20 19.45% 0.54
X-ray 2.96 0.20 19.41% 0.37

Visual Inspection of C-Flex® 374 tubing

Sani-Tech® Ultra-C

Opacity and yellowness were measured on Sani-Tech® Ultra-C following gamma and X-ray irradiation and compared to a control. The yellowness value of the tubing that was gamma irradiated was higher than the tubing that was X-ray irradiated as seen in the table below. A visual inspection was performed and there was little to no difference between the gamma and X-ray sample sets.

Sani-Tech® Ultra-C Yellowness Index
(Average of 10)
Standard Deviation
(Sample set of 10)
Opacity
(Average of 10)
Standard Deviation
(Sample set of 10)
Control 5.56 0.37 16.64 0.43
Gamma 6.20 0.26 16.81 0.49
X-ray 5.86 0.50 17.42 0.49

Visual Inspection of Sani-Tech® tubing

5.2 Differential Scanning Calorimetry (DSC)

C-Flex® 374 Tubing C-Flex® 374 Differential Scanning Calorimetry (DSC)

Plots collected as part of the DSC testing completed on all sterilization types of C-Flex® 374 are seen below in Figure 24 as well as the noted transition temperatures for each. The midpoint for the glass transition of each sterilization type falls approximately at the same temperature, regardless of sterilization type. No changes were observed to the glass transition behavior of C-Flex® 374 after either gamma or X-ray irradiation. 
 

 

5.5 Mechanical Evaluation of Materials

5.5.1 Durometer

Durometer is a measurement of hardness that is often performed on elastomeric materials.

 

 

C-Flex® 374 (TPE) Tubing

The durometer of C-Flex® 374 was measured on 10 samples after gamma and X-ray irradiation. The results demonstrate equivalence between samples that were gamma and X-ray irradiated. As seen in the Table 26, the durometer of C-Flex® 374 decreases with both gamma and X-ray irradiation. The results suggest an equivalence between gamma and X-ray irradiation.

Batch Shore A Durometer Standard Deviation
(Sample set of 10)
C-Flex® 374 – Control 55 0.28
C-Flex® 374 – Gamma 53 0.43
C-Flex® 374 - X-ray 53 0.51

Table 26: Durometer of C-Flex® 374

Sani-Tech® Ultra-C (Pt. Cured silicone) Tubing

The durometer of Sani-Tech® Ultra-C was measured on 10 samples after gamma and X-ray irradiation. The results demonstrate equivalence between samples that were gamma and X-ray irradiated. As seen in the Table 27, the durometer of Sani-Tech® Ultra-C increased after both gamma and X-ray irradiation, typical of silicone materials due to cross-linking.

Batch Shore A Durometer Standard Deviation
(Sample set of 10)
Sani-Tech® Ultra-C – Control 47 0.74
Sani-Tech® Ultra-C – Gamma 52 0.53
Sani-Tech® Ultra-C - X-ray 50 0.12

Table 27: Durometer of Sani-Tech® Ultra-C

5.5.2 Tensile Strength

C-Flex® 374 TPE Tubing C-Flex® 374 Tensile Strength and Elongation

Tensile Strength and Elongation was measured on 10 samples of C-Flex® 374 after gamma and X-ray irradiation. The results demonstrate equivalence between samples that were gamma and X-ray irradiated.  
 

5.7 Tear Strength

C-Flex® 374 Tubing C-Flex® Relative Average Tear Resistance Results

Tear strength measures a material’s resistance to propagation of a rip or tear once the rip has been initiated. This test is important for rubber and TPEs as they often fail in service due to a rip or tear. As seen below in Figure 39, similar behavior was witnessed after tear resistance testing. Statistical analysis done comparing the tear resistance of the three sterilization types showed no significant difference.  
 

5.8 Compression Set Testing

C-Flex® 374 Tubing  C-Flex® 374 Average Compression Set

Compression set measures the residual deformation after compressive loading under specified conditions. Compression set testing was performed on 10 tubing samples of C-Flex 374® tubing after gamma and X-ray irradiation. The results demonstrate equivalence between samples that were gamma and X-ray irradiated. It is typical for C-Flex® 374 to decrease in compression set % following irradiation. Figure 41 displays the average of the 10 samples from each testing group. 

Sani-Tech® Ultra-C Tubing

6. Biological Tests

C-Flex® 374 Tubing (TPE) and Sani-Tech® Ultra-C Tubing (Pt. Cured Silicone)

Biological Reactivity in vitro testing was performed on gamma and X-ray irradiated C-Flex® 374 and Sani-Tech® Ultra-C tubing using the USP <87> MEM Elution method. Results show that neither sample set show cytotoxic potential to L-929 mouse fibroblast cells. Both gamma and X-ray irradiated C-Flex® 374 tubing and both gamma and X-ray irradiated Sani-Tech® Ultra-C Tubing (Pt. Cured Silicone) meet the requirement of the USP <87> of a less than or equal to grade 2 (mild reactivity). 

Published by Bio-Process Systems Alliance (BPSA) 

For more information about BPSA, visit www.bpsalliance.org

To learn more from other contributors and to read the full report, you can download the white paper below.

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X-Ray Sterilization of Single-Use Bioprocess Equipment

Part II - Representative Qualification Data
In collaboration with Bio-Process Systems Alliance (BPSA)

PDF | 65 pages | 3.8 MB
X-Ray Sterilization of Single-Use Bioprocess Equipment
X-Ray Sterilization Information

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