Understanding USP Class VI Category of Medical Device Raw Materials

USP Class VI is a classification established by the United States Pharmacopeia (USP) to assess the biocompatibility of medical-grade materials used in medical devices, pharmaceuticals, and biological applications. It is considered one of the most stringent standards for medical device raw materials, ensuring they are safe for prolonged human contact, including implantation.

What is USP Class VI?

USP (United States Pharmacopeia) Class VI certification is the highest classification for biocompatibility under USP standards. It ensures that materials used in medical devices, pharmaceuticals, and healthcare applications do not induce toxicity, irritation, or long-term adverse effects in living tissues.

Materials that achieve USP Class VI compliance must pass rigorous testing to demonstrate that they do not leach harmful chemicals, degrade in a way that impacts human health, or cause irritation upon prolonged exposure to biological tissues.

Why is USP Class VI Important for Medical Devices?

Medical devices, especially those that come into direct or prolonged contact with bodily tissues and fluids, must be free from harmful chemicals, toxins, and potential contaminants. USP Class VI certification ensures that the raw materials used in these devices are:

  1. Non-toxic – They do not release harmful substances when in contact with the human body.
  2. Biocompatible – They do not trigger adverse reactions such as irritation, inflammation, or toxicity.
  3. Sterilizable – They maintain structural and chemical stability after sterilization processes such as autoclaving, gamma radiation, or ethylene oxide exposure.

Tests Conducted for USP Class VI Compliance

To achieve USP Class VI certification, materials must pass three critical tests:

1. Systemic Toxicity Test (Acute Toxicity)
  • Evaluates whether the material, when injected into a living organism, causes any toxic effects.
  • Conducted by administering an extract of the material into mice or rabbits and monitoring for adverse reactions over 72 hours.
  • Ensures that no immediate toxic responses such as convulsions, paralysis, or fatality occur.
2. Intracutaneous Reactivity Test (Irritation Test)
  • Determines if the material causes irritation when introduced into tissue.
  • Conducted by injecting the material into the skin of test animals and checking for redness, swelling, or inflammation.
  • A key factor in ensuring the safety of materials that will have prolonged skin or mucosal contact.
3. Implantation Test (Subcutaneous Implantation)
  • Assesses tissue response when the material is implanted into a living organism.
  • Observes inflammatory reactions, fibrous capsule formation, or necrosis at the implantation site.
  • Critical for ensuring the long-term biocompatibility of medical devices.

Relevance to Menstrual Cups as a Class B Medical Device

Menstrual cups are classified as Class B medical devices in many regulatory frameworks, meaning they require moderate risk assessment due to their extended use in the vaginal environment. Since menstrual cups remain in contact with sensitive mucosal tissues for long durations, it is critical to ensure that the material:

  • Does not cause irritation or inflammation
  • Is free from leachable chemicals that could disrupt vaginal pH
  • Maintains stability even after repeated sterilization cycles

By adhering to USP Class VI standards, menstrual cup manufacturers can ensure their products meet the highest safety requirements for long-term intimate use, protecting consumers from potential health risks.

The Role of ISO 10993 and USP Class VI in Menstrual Cup Safety

For menstrual cups to be deemed safe for medical use, they must comply with both ISO 10993 biocompatibility standards and USP Class VI classification. These regulatory frameworks work together to ensure:

  • Material safety: No harmful substances leach into the vaginal environment.
  • Irritation-free usage: No risk of discomfort, redness, or swelling.
  • Toxicity prevention: No immediate or long-term toxic reactions.

Ensuring Compliance for Menstrual Cups

For manufacturers, compliance with USP Class VI and ISO 10993 involves rigorous material selection, laboratory testing, and regulatory approvals. Here are some best practices to ensure compliance:

  1. Use Medical-Grade Silicone or TPE: Select raw materials that have already been tested for medical applications.
  2. Conduct ISO 10993 Testing: Include cytotoxicity, sensitization, and vaginal irritation tests to confirm biocompatibility.
  3. Adhere to USP Class VI Standards: Ensure that materials undergo systemic toxicity, intracutaneous reactivity, and implantation tests.
  4. Monitor Production and Quality Control: Regular audits and batch testing to ensure continued compliance.

Conclusion

Ensuring that menstrual cups meet USP Class VI material standards is essential for product safety, regulatory approval, and consumer confidence. Because menstrual cups remain in direct contact with vaginal tissues for prolonged periods, their materials must be free from irritants and toxic substances.

By adhering to internationally recognized standards such as ISO 10993 and USP Class VI, menstrual cup manufacturers can ensure their products are safe, comfortable, and suitable for long-term use. These rigorous safety measures not only protect consumers but also strengthen the credibility of brands in the menstrual care industry.

For businesses seeking compliance with these stringent safety standards, collaborating with certified laboratories and following best practices in material selection and regulatory testing is crucial for ensuring product safety and success in the global market.