Biological Evaluation of Medical Devices ISO 10993

Biological evaluation of medical devices is a critical process to assess potential biological risks when devices come into contact with the human body, primarily based on the ISO 10993 series of standards. Below are the core contents:

Overview of Evaluation Process

• Material Characterization: Identify material composition, processing additives, contaminants, etc.

• Contact Nature: Evaluate contact type (surface contact, implantation, blood contact, etc.), duration (short-term, long-term, permanent), and contact site.

• Biological Testing: Select necessary in vitro or in vivo tests based on risk.

Main Evaluation Items

(1) Cytotoxicity (iso 10993-5)

• Purpose: Detect toxic effects on cells (e.g., growth inhibition, cell death).

• Method: In vitro tests (MTT assay, agar diffusion test, etc.).

(2) Sensitization (iso 10993-10)

• Purpose: Assess potential allergic reactions (e.g., skin sensitization).

• Method: Guinea pig maximization test (GPMT) or local lymph node assay (LLNA).

(3) Irritation or Intradermal Response (ISO 10993-10)

• Purpose: Evaluate irritation to skin, mucous membranes, or eyes.

• Method: Rabbit skin irritation test, in vitro reconstructed skin model, etc.

(4) Systemic Toxicity (Acute / Subacute / Chronic) (iso 10993-11)

• Purpose: Assess adverse systemic effects (e.g., fever, organ toxicity).

• Method: Animal tests (e.g., acute toxicity test in mice).

(5) Genotoxicity (ISO 10993-3)

• Purpose: Determine potential DNA damage (carcinogenic risk).

• Method: Ames test (bacterial mutation), chromosome aberration test, etc.

(6) Local Effects After Implantation (iso 10993-6)

• Purpose: Evaluate inflammation, fibrosis, and other local responses post-implantation.

• Method: Animal implantation tests (subcutaneous, muscle, or bone implantation).

(7) Hemocompatibility (ISO 10993-4)

• Purpose: Assess effects on blood (hemolysis, thrombosis, platelet activation, etc.).

• Method: In vitro hemolysis test, dynamic coagulation time assay, etc.

(8) Subchronic / Chronic Toxicity (iso 10993-11)

• Purpose: Toxic effects under long-term exposure (e.g., organ damage, immune response).

• Method: Long-term animal studies (usually 90 days or longer).

(9) Carcinogenicity (ISO 10993-3)

• Purpose: Assess tumor induction risk after long-term exposure.

• Method: Long-term animal studies (usually 2 years), mainly for implants.

(10) Reproductive and Developmental Toxicity (ISO 10993-3)

• Purpose: Evaluate impacts on reproductive system or fetus (required for contraceptive devices).

• Method: Animal tests (e.g., rat embryo-fetal development study).

Supplementary Evaluations

• Degradation Product Analysis (for absorbable materials): Assess toxicity of degradation products (ISO 10993-9, 13).

• Immunotoxicity: For devices that may trigger immune responses (e.g., devices containing biological materials).

• Neurotoxicity: For devices in contact with the nervous system.

Waiver Principles

• Existing Data: Reduce or waive certain tests if the material has a long safe-use history.

• Risk Assessment: Use chemical characterization (e.g., extractables analysis) plus toxicological data to replace some biological tests.

Standards & Regulatory Basis

• International Standard: ISO 10993 series (widely adopted by EU, US, etc.).

• Chinese Standard: GB/T 16886 series (essentially aligned with ISO 10993).

• FDA / EMA / NMPA Requirements: Comply with additional guidelines from local regulators.

Notes

• Material Changes: Re-evaluation required for any material or process modification.

• Clinical Data: Some high-risk devices require combined analysis with clinical trial data.

Through systematic evaluation, medical devices are ensured not to pose unacceptable biological risks during intended use. Test selection is based on device type, contact mode, and duration, following the risk minimization principle.