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Derek Nexus

Expert, knowledge-based software that gives you accurate toxicity predictions quickly.

  • Derek Nexus is a knowledge-based software which gives predictions for a variety of toxicological endpoints.
  • Derek Nexus can be used as part of an ICH M7 workflow.
  • Derek Nexus gives quantitative EC3 predictions for skin sensitisation.
  • Negative predictions for bacterial mutagenicity are provided when no alert is fired.


 Why do you need Derek Nexus? 

General Approach

How Derek Nexus can be used


Features and Benefits

Negative Predictions for Bacterial Mutagenicity

EC3 Predictions for Skin Sensitisation

Derek Knowledge Editor and Web Services 


Why do you need Derek Nexus?

Whether your industry is cosmetics, pharmaceuticals, chemicals, or you are in academia, Derek Nexus enables you to:

  • Evaluate the potential toxicity of existing or prospective chemicals.
  • Make decisions about which chemicals are likely to have ‘more favourable’ toxic profiles when you do not have all the experimental information you would like to have about the toxicity of each chemical.
  • Share internal toxicity data and knowledge with your colleagues by capturing it within Derek Nexus.
  • Improve the properties of a chemical in the R&D pipeline by slightly redesigning its molecular structure.
  • Save time and money by carrying out toxicity experiments on a large number of chemical candidates and selecting those with the most favourable outlook.
  • Learn using the extensive knowledge in the expert software as a toxicology training tool.

General Approach

When a structure is submitted to Derek Nexus, it is compared to the certified Lhasa knowledge base and any custom knowledge bases that you have created using Derek Knowledge Editor, and a toxicity prediction is generated.

The Derek Nexus prediction includes an overall conclusion about the likelihood of toxicity of a structure and detailed reasoning information for the likelihood. The prediction is generated by applying expert knowledge rules in toxicology to the data returned from the knowledge base.


Derek Nexus predicts potential toxicity for most toxicological endpoints, including:

Derek Knowledge Base

The certified Derek knowledge base, created and supplied by Lhasa Limited, contains data from published sources and data donated by our member organisations. This data is collated, checked and verified by Lhasa scientists before being used to develop new knowledge rules and relationships. These rules and relationships are based on empirical observations that are supported by an understanding of the toxicity mechanism or by our rigorous, internal vetting process.

How Derek Nexus can be used

Derek Nexus is the expert, knowledge-based software that gives you accurate toxicity predictions quickly. Early, accurate in silico toxicity tests using Derek Nexus is the quick, inexpensive way to identify potentially toxic chemicals, aiding your experts in rejecting unsuitable drug candidates.

Derek Nexus has various uses, including:

  • Bacterial Mutagenicity Screening
  • 2-Stage Processing
  • Screening and Compound Profiling
  • Genotoxic Impurities (GTI) Assessment & Management

Bacterial Mutagenicity Screening

In silico screening using Derek Nexus provides an early indication of potential mutagenic compounds and therefore reduces late stage attrition due to unforeseen toxicity (Escobar et al., 2013).

2-Stage Processing (Figure 1)

Various Derek Nexus users operate a 2-stage process. Stage 1 involves reviewing the high-level overview and stage 2 involves delving further into the details. In practice, this means that users can start with a simple prediction of potential toxicity, and if further information is required, users can interrogate the expert summary which contains additional material.

Figure 1: The 2-stage processing method using Derek Nexus 

Screening & Compound Profiling

The transparency of predictions within Derek Nexus allows for data analysis, to prioritise lead series of compounds. Derek Nexus is designed with this workflow in mind, allowing:

  • Toxicity predictions for thousands of compounds for prioritisation for future development.
  • Detailed analysis of individual or multiple compounds facilitating decision making.

In each case, Derek Nexus provides the breadth and depth of information required.

Potential Mutagenic Impurities (PMI) Assessment and Management 

Derek Nexus is widely used to assess PMIs and is used commonly within the pharmaceutical industry (Dobo et al., 2012) for management of mutagenic impurities knowledge. Derek Nexus enables organisations to meet half of the requirements of ICH M7, and is supported further by:

  • Sarah Nexus; a statistical software for the prediction of mutagenicity
  • Vitic Nexus; holding a vast amount of relevant data
  • Mirabilis; expert and scientifically robust software for the calculation of purge factors of potentially mutagenic impurities in a synthetic route
  • Lhasa Carcinogenicity Database; a free, online database for the retrieval of relevant carcinogenicity data

 Scientists use the tools in conjunction to perform read-across studies allowing users to make decisions across all available data.


  • Dobo et al. (2012) ‘In silico methods combined with expert knowledge rule out mutagenic potential of pharmaceutical impurities: An industry survey’, Regulatory Toxicology and Pharmacology, vol. 62, no. 3, April, pp.449-455. http://dx.doi.org/10.1016/j.yrtph.2012.01.007

  • Escobar et al. (2013) ‘Bacterial mutagenicity screening in the pharmaceutical industry’, Mutation Research, vol. 752, no. 2, April-June, pp.99-118. http://dx.doi.org/10.1016/j.mrrev.2012.12.002


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