Contaminants such as cytotoxins and pyrogens can pose serious risks to cell cultures, pharmaceutical research, and clinical applications. To maintain high safety standards, manufacturers adhere to rigorous testing protocols such as USP 87 (In Vitro Cytotoxicity Testing) and USP 88 (In Vivo Biological Reactivity Testing).
This article will explore what cytotoxins and pyrogens are, how they impact biomedical applications, and the role of USP 87 and USP 88 testing in ensuring the safety of tissue culture plastics and medical devices.
What Are Cytotoxins and Pyrogens?
- Cytotoxins are substances that can damage or destroy living cells. In laboratory plastics and medical devices, residual chemicals, additives, or degraded polymer byproducts may introduce cytotoxic effects, impacting cell viability and research outcomes.
- Pyrogens are fever-inducing contaminants, primarily bacterial endotoxins, that can trigger immune responses if introduced into the body through medical devices, injectable drugs, or laboratory plastics.
To ensure the safety of medical and lab-grade plastics, manufacturers perform both in vitro (USP 87) and in vivo (USP 88) biocompatibility testing.
USP 87: In Vitro Biological Reactivity (Cytotoxicity Testing)
USP 87 outlines a set of in vitro (cell-based) tests to evaluate whether a material is cytotoxic. This test is widely used in laboratory plastics manufacturing to ensure that products like pipette tips, centrifuge tubes, deep well plates, and tissue culture flasks do not negatively impact cell growth.
How USP 87 Testing is Conducted:
- Extraction Process: The test material is incubated in a biological solution to extract any potential leachable cytotoxins.
- Cell Exposure: The extract is introduced to cultured mammalian cells.
- Observation: Scientists assess cell viability, morphology, and metabolic activity to determine whether the material exhibits cytotoxic effects.
Why It Matters: USP 87 ensures that laboratory plastics used in cell culture and pharmaceutical research do not release toxic substances that could impact experimental accuracy.
USP 88: In Vivo Biological Reactivity (Pyrogen & Biocompatibility Testing)
While USP 87 focuses on in vitro testing, USP 88 evaluates in vivo (animal-based) biological reactivity to ensure full-body safety and biocompatibility. It classifies medical plastics into four classes (I, II, III, IV) based on their intended use and level of patient exposure.
How USP 88 Testing is Conducted:
- Systemic Injection Test: A test material extract is injected into laboratory animals to observe any adverse biological responses.
- Intracutaneous Reactivity Test: Examines localized reactions when the material is exposed to tissues.
- Implantation Test: Evaluates long-term biocompatibility by implanting the material and monitoring for reactions.
Why It Matters: USP 88 confirms that medical and laboratory plastics are free from harmful pyrogens and bioreactive contaminants, making them safe for use in pharmaceutical, biomedical, and clinical applications.
Ensuring that laboratory and medical plastics are free from cytotoxins and pyrogens is essential for cell culture research, drug development, and patient safety. USP 87 and USP 88 testing play a crucial role in verifying biocompatibility and regulatory compliance, helping manufacturers deliver safe, high-quality lab consumables for scientific and medical use.
