Draize testing also fails to elucidate the underpinning cellular and molecular mechanisms Pirfenidone clinical trial of toxicology. Since Draize assessments are based upon penlight or slit-lamp assessments,

they provide very little information regarding the primary or secondary responses in the cornea, iris or conjunctiva (Maurer et al., 2002). Despite its “gold standard” status, Draize testing was never formally validated to any significant degree (Freeberg et al., 1986b). Since the anatomy of the rabbit eye differs from the human eye structurally, physiologically and biochemically, differences in sensitivity to irritants can occur. For example, in comparison to humans, rabbit corneas are thinner, have lower tear production, blinking frequency and ocular surface sensitivity (Huhtala et al., 2008). Rabbits have larger conjunctival sacs and a nictitating membrane (third eyelid), which may aid the removal of a test substance from the ocular surface (Calabrese, 1987). There is almost no other field of science in which the fundamental experimental protocols have remained relatively unchanged for more than 40 years (Hartung, 2009), and yet consumers continually expect increased BIBF 1120 chemical structure safety and information

regarding their products. Worldwide, approximately £10 billion is spent on animal experimentation per annum, approximately £2 billion of which is on toxicological studies (Hartung, 2009). The cost associated with using, housing and maintaining colonies of live animals for toxicology testing of a single compound can exceed millions of pounds (Davila et al., 1998). Ethical (animal welfare), business (time and cost), scientific advances (reproducibility, mechanistic understanding) and legal concerns have all driven the demand for alternative, preferably animal-free testing platforms and protocols which are more precise and relevant to humans. There has been more focus on developing alternative testing techniques to Draize than all other in vivo

toxicity tests combined ( Huhtala et al., 2008). However, the development of alternative Quisqualic acid models has not advanced in a steady or continuous manner ( Dholakiya and Barile, 2013), although the ban on animal testing for cosmetics use (Regulation (EC) No. 1223/2009) has acted as a key driver for the development of alternative methods since this sector is constantly having to provide innovative and safe products. In Europe, with directive 2010/63/EU, there is a legal requirement to use alternatives where they exist. However, the reduction of animal use is primarily concentrated on toxicology studies since no government agency to date has eliminated animal use in basic biomedical research or pharmaceutical development. Low-volume eye-irritation tests (LVET) were developed in response to a recommendation from the National Research Council (NRC, 1977).