Endotoxin Limits for Medical Devices According to USP Chapter 161

According to USP Chapter 161, “Transfusion and Infusion Assemblies and Similar Medical Devices,” endotoxin limits for medical devices are as follows:

For devices that come into direct or indirect contact with the cardiovascular system and lymphatic system, the endotoxin limit is 0.5 EU/mL or 20 EU/device.

For devices in contact with cerebrospinal fluid, the limit is 0.06 EU/mL or 2.15 EU/device. For devices that are in direct or indirect contact with the intraocular environment, a lower endotoxins limit may apply. Please contact the appropriate review division for specific recommendations.

Extraction volume recommendations can be found here.

Bacterial Endotoxins Testing Method

Bacterial endotoxins are tested using the Limulus Amebocyte Lysate (LAL) assay, which is a precise testing method designed to detect the presence of endotoxins in samples.

The LAL assay is based on the fact that the blood of horseshoe crabs contains a substance called amebocyte lysate that reacts with bacterial endotoxins. The lysate is obtained by collecting the blood of the horseshoe crab and separating the cells from the plasma. The lysate is then mixed with the sample being tested, and the mixture is observed for the formation of a clot.

If endotoxins are present in the sample, the amebocyte lysate will react with them, leading to the formation of a clot. The time it takes for the clot to form is proportional to the amount of endotoxin in the sample. This reaction is measured quantitatively by a spectrophotometer, and the results are reported in units of endotoxin per milliliter of sample.

The LAL assay is a highly sensitive test that can detect endotoxins at very low levels. It is commonly used in the pharmaceutical and biotechnology industries to ensure the safety and purity of drugs and medical devices.

Manufacturing Low Endotoxin Supplies

To ensure a product endotoxin-free, the manufacturing process should be carefully designed to avoid any contamination with endotoxins. Endotoxins are heat-stable and can be resistant to many common disinfectants, so it is essential to use a combination of methods to ensure that the wipes are endotoxin-free.

The following are steps that can be taking in the manufacturing process to ensure products are free of endotoxins:

  1. Raw material selection: Choosing raw materials that are free from endotoxins, such as high-purity water, and using only approved vendors.
  2. Manufacturing process: Designing a process that minimizes the exposure of the product to endotoxins. This can include using high-temperature steam or other sterilization methods to kill any bacteria that might be present.
  3. Quality control: Conducting regular testing of both the raw materials and finished wipes to ensure that they are endotoxin-free. This can include using the LAL assay or other sensitive tests to detect the presence of endotoxins.
  4. Packaging and storage: Ensuring the products are packaged and stored in a way that prevents any contamination with endotoxins.