Developed in 1944 by Food and Drug Administration (FDA) toxicologists John H. Draize and Jacob M. Spines, the Draize test emerged as a method for assessing the potential toxicity of chemical substances. Its original purpose was to ensure product safety, particularly for cosmetics, by evaluating their irritant properties. This test served as a standard procedure for decades.
Understanding the Draize Test
The Draize test is an acute toxicity assessment, primarily for eye (ocular) and skin (dermal) irritation. Albino rabbits are commonly used due to their large eyes and ease of handling. In the ocular test, a substance is applied to one eye of a restrained, conscious rabbit, with eyelids often held open. For dermal irritation, the substance is applied to shaved skin.
Animals are observed for up to 14 days after application. Researchers score reactions on a numerical scale, assessing damage to the cornea, iris, and conjunctiva. Effects can range from redness, swelling, and discharge to ulceration, hemorrhaging, cloudiness, or blindness. For skin tests, erythema (redness) and edema (swelling) are the primary indicators. Historically, this methodology became a standard for evaluating the safety of various products, including insecticides and sunscreens.
Ethical and Scientific Criticisms
The Draize test has faced ethical and scientific scrutiny, leading to calls for its replacement. Ethically, the procedure inflicts suffering and pain on animals. They often experience burning, itching, and discomfort, with chemicals causing severe reactions like ulcerated eyes, bleeding, blindness, or scarring. Animals are restrained for up to 14 days, preventing them from relieving discomfort. If irreversible damage occurs, animals may be euthanized.
Scientifically, the test has limitations in predicting human reactions. A primary concern is anatomical and physiological differences between rabbit and human eyes and skin. Rabbit eyes, for instance, have a third eyelid, differ in tear production, and are more permeable to some substances, making them a less-than-ideal human model. Visual scoring is subjective, leading to variable outcomes between laboratories. This inconsistency and biological disparity mean Draize test results do not always reliably reflect human exposure or predict safety.
The Rise of Alternatives
Concerns over animal welfare and scientific limitations have driven the development of non-animal testing methods. These alternatives fall into two categories: in vitro (cell-based) and in silico (computational) approaches. In vitro methods use human cells, tissues, or reconstructed human models, like corneal cell lines, to assess irritation. These tests mimic human biological responses and show how substances interact with cells. Examples include the Bovine Corneal Opacity and Permeability (BCOP) assay and the Isolated Chicken Eye (ICE) test, accepted for regulatory purposes.
In silico methods use computer modeling to predict chemical irritancy based on molecular structure. These tools offer high speed and low cost, allowing rapid screening of many compounds. Efforts are also underway to integrate in vitro and in silico data into comprehensive strategies. These combine evidence for a more robust, reliable, and humane safety assessment without animals.
Global Regulatory Shifts
The Draize test’s use has declined globally, with many regions restricting or banning animal testing for cosmetics. The European Union leads this movement, banning cosmetic ingredient animal testing since 2009 and prohibiting marketing of animal-tested cosmetics since 2013. This ban, part of EU Cosmetics Regulation 1223/2009, demonstrates a commitment to non-animal methods.
Beyond the EU, many countries have enacted similar prohibitions. India banned cosmetic animal testing in 2013 and import of animal-tested cosmetics in 2014. Other nations with bans or significant restrictions include:
Israel
Norway
The United Kingdom
Colombia
Canada
Taiwan
South Korea
Australia
Brazil
Ecuador
Guatemala
Iceland
Mexico
New Zealand
Switzerland
Turkey
While countries like China historically required animal testing for some imported cosmetics, regulations have evolved, allowing some ordinary cosmetics to be imported without such testing. This global trend reflects a shift towards advanced, humane non-animal safety assessment methods.