YY/T 1746-2020Absorbable surgical suture—Test method for breaking strength in vitro hydrolytic degradation (English PDF)

3.1 Material testing machine

The tensile speed is 300 mm/min ± 10 mm/min; the test gauge length is 130 mm ± 5 mm.

Note: If the suture length cannot meet the requirements of the specified test gauge length, the test gauge length can be adjusted according to the actual length of the suture; the corresponding stretching speed is set to 2 times the adjusted test gauge length. If the adjusted test gauge length is set to 50 mm, the stretching speed is set to 2×50 = 100 mm/min.

3.2 Electric-heating constant-temperature oscillating water tank or constant-temperature oscillator

The temperature is 37 °C ± 1 °C; the oscillation frequency: 60 r/min (or other suitable oscillation methods).

3.3 pH meter

The accuracy of the pH meter is not less than 0.02.

3.4 Container

4.3 Test of residual breaking strength

4.3.1 Take 10 sutures of the same batch as the initial test value (4.2); put them into the container (3.4), so that the sutures are completely immersed in the test solution (3.5) (the ratio of the volume of the test solution to the mass of the suture is at least 10 mL:1 g).

Note: If the suture length can meet the test conditions, take the same suture to test the initial breaking strength value and the residual breaking strength value, respectively.

4.3.3 At the end of the test period, take out the suture and remove the water on the surface of the suture until there is no dripping.

Note: The method of removing water shall not affect the breaking strength of the suture.

4.3.5 Calculate the average of the 10 recorded force values, which is the residual breaking strength.

4.3.4 Carry out the test according to steps 4.2.1 ~ 4.2.3

4.3.2 Incubation

Place the container in the electric-heating constant-temperature. oscillating water tank (3.2); select the corresponding test period according to the material of the suture and the intended use. During the test period, the pH value of the test solution in the container shall be monitored as needed. If the pH value of the buffer exceeds the specified limit value (7.4 ± 0.2), use the 0.1 mol/L sodium hydroxide solution or dilute phosphoric acid to adjust or replace the buffer, to make it meet the requirements (3.5).

4.4 Result calculation

Calculate the retention value of breaking strength according to Formula (1):

Where: BSR -- Retention value of breaking strength; F0 -- Initial breaking strength; F1 -- Residual breaking strength. […]