Test Description
The USP Agar Diffusion Method is a cytotoxicity test used to evaluate the biocompatibility of medical devices by assessing their potential to release toxic substances. In this method, a test material is placed on an agar layer that overlays a monolayer of cultured cells. Leachables from the material diffuse through the agar and interact with the cells. The extent of cell damage or lysis is then evaluated microscopically, offering a sensitive and indirect measure of cytotoxicity.
Why This Testing is Performed
This test is essential for identifying whether medical device materials release cytotoxic substances that could harm surrounding tissues. It is particularly useful for materials that do not directly contact cells but may release leachables. The method supports regulatory compliance.
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Steps in Conducting This Test
- Cell Culture Preparation: Grow a monolayer of L929 mouse fibroblast cells in a culture dish.
- Agar Overlay: Apply a thin layer of agar over the cell monolayer to act as a diffusion barrier.
- Sample Placement: Place the test material or its extract on top of the agar layer.
- Incubation: Incubate the setup at 37°C for 24 hours to allow diffusion of leachables.
- Evaluation: Assess cytotoxicity by observing zones of decolorization and cell lysis under a microscope.
- Scoring: Assign a cytotoxicity grade based on the size and intensity of the affected area.
Standards, Guidance, and Regulations
- USP <87>: Specifies procedures for in vitro biological reactivity tests, including the agar diffusion method.
- ISO 10993-5: Provides international guidance for in vitro cytotoxicity testing.
- GLP Compliance (21 CFR Part 58): Ensures data integrity for regulatory submissions.
| Test Code |
|---|
| V0010-110 |
