An in-vitro toxicity testing - a reliable alternative to toxicity testing by reduction, replacement and refinement of animals.

In the past few years, many in vitro methods for animal toxicity testing have been developed, validated, as a alternative to whole animal tests and it gained regulatory acceptance due to ethical and scientific concerns regarding the use of animals. These alternative methods are developed and validated using Reduction, Replacement and Refinement - 3Rs approach. A range of non animal methods are available which includes: Physiology based Pharmacokinetic modeling, computerized modeling, use of non mammalian models, variety of cell and tissue cultures, endpoint assays, microarray technology, human clinical trials utilizing microdosing and epidemiological studies, use of –omics technologies. These non animal models may generate more reliable, faster and cheaper results and may also provide mechanistic depth. Considerable progress in the development of alternative methods have been made in some fields such as dermal toxicity, ocular toxicity, reproductive and developmental toxicity, carcinogenicity, hepatotoxicity, neurotoxicity, biologicals testing. There is still a lack of 3Rs alternatives for systemic and long-term toxicity. New approaches such as integrated tiered strategies have been developed. This article reviews the alternative technologies in assessing the human risks and providing protection against the hazards. There is a need for the implementation, validation and rapid regulatory acceptance to meet the emerging testing needs.