Laboratory testing of hemolytic properties of materials that come in contact with blood: Comparative application testing method’s two variants according to the standard ASTM F756 in accordance with ISO 10993-4
The presence of hemolytic material in contact with blood may produce increased levels of blood cell lysis and increased levels of plasma hemoglobin. This may induce toxic effects or other effects which may stress the kidneys or other organs. In this paper two variants of in vitro method and obtained results? comparison were presented for testing of hemolytic properties of six raw materials (Polipropylene Moplen EP 540 P, Policarbonate colorless 164 R-112, Policarbonate brown 164 R-51918, Polietylene NG 3026 K, Polietylene NG - Purell GB 7250, Polietylene VG - Hiplex 5502) for medical device manufacturing and one raw material (Polietylen NG granulate) used for infusion solutions?s plastic bottles manufacturing. One of method?s variants relies on raw material direct contact with swine blood and the other on extract of the material contact with swine blood. Both method?s variants imply reading of the absorbance of the supernatant after tubes were incubated and centrifuged. According to values obtained and using the standard curve free hemoglobin concentration is determined and based on this percentage hemolysis of raw material. Positive and negative controls were used in both variants where water for injection (WFI) was used as positive control in which partial or complete hemolysis of erythrocytes occurs due to osmotic shock and phosphate buffer saline was used as negative control with no hemolytic property. In this paper comparison of results obtained by both method?s variants for testing of seven raw materials was presented, while these conclusions can not be used neither for all materials, nor for all applications without preliminary testing using both variants and then choosing more sensitive and more reliable one. It was shown and stated in the paper as well that incubation time being 3, 15 or 24 h, had no impact on the variant?s with direct contact sensitivity. This comparative approach was used for drawing conclusions in terms of suitability for application of one or the other method?s variant, as well as for defining relevant incubation time and finally for choosing more sensitive and more reliable variant for assessment of hemolytic properties of raw materials. Variant with direct contact was chosen from the aspect of less complexity regarding necessary laboratory equipment which makes it economically more favorable and fit for the purpose.