Class Plastics Testing – USP <88>

USP <88> Class Plastic Tests are designed to assess the biological reactivity of various types of plastics materials in vivo. Originally developed to test drug containers, the USP class plastics tests are often performed on unmolded plastic resins as well as containers. Class plastics testing is not a substitute for testing performed according to ISO standards, but is often used by manufacturers to classify/certify materials. The USP defines six plastics classes, from class I to class VI with class VI being the most rigorous but most frequently requested certification.

Many plastics manufacturers find it advantageous to have their materials classified, especially if their plastic resins are a likely candidate to be used in medical devices. A plastic material that has passed the USP Class Plastics tests are expected to be more likely to produce favorable biocompatibility results.

There are three in vivo tests involved in the classification of plastics.  The Systemic Injection Test and the Intracutaneous Test are designed to determine the systemic and local biological responses to plastics and other polymers by the single-dose injection of specific extracts prepared from a sample.  The third test, the Implantation Test, is designed to evaluate the reaction of living tissue to a test material. The testing for the six different class plastics levels is all done using different combinations of these three tests and different extracts.

USP Class VI Certification

USP Class VI requires the most testing of the six USP class plastic groups.  The following tests are needed for USP Class VI plastic certification:

  • Extract of sample in NaCl, Systemic Injection Test in mouse (intravenous)
  • Extract of sample in NaCl , Intracutaneous Test in rabbit
  • Extract of sample in 1:20 solution of alcohol in NaCl, Systemic Injection Test in mouse (intravenous)
  • Extract of sample in 1:20 solution of alcohol in NaCl, Intracutaneous Test in rabbit
  • Extract of sample in polyethylene glycol 400, Systemic Injection Test in mouse (intraperitoneal)
  • Extract of sample in polyethylene glycol 400, Intracutaneous Test in rabbit    
  • Extract of sample in vegetable oil, Systemic Injection Test in mouse (intraperitoneal)
  • Extract of sample in vegetable oil, Intracutaneous Test in rabbit
  • Extract of sample in vegetable oil, Systemic Injection Test in mouse (intraperitoneal)
  • Extract of sample in vegetable oil, Intracutaneous Test in rabbit
  • Implant strip of sample in Rabbit
  • Implant sample in rat

Class VI plastics will need to be certified against all of the tests, but the other classes of USP plastics will be tested against only a portion of the tests described above.

USP Class Plastics Testing Services

  • USP Systemic Injection Test
  • USP Intracutaneuous Test
  • USP Implantation Test

Read More About USP Class Plastics

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