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Derek Nexus

Expert, knowledge-based software that gives fast and accurate toxicity predictions.

  • Derek Nexus is expert, knowledge-based toxicology software which gives predictions for a variety of 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 and skin sensitisation are provided when no alert is fired.


Features and Benefits

Derek Nexus for ICH M7

Derek Nexus for Skin Sensitisation

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 through the Derek Knowledge Editor.
  • 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.

To see a list of our current member organisation, click here

General Approach

When a structure is submitted to Derek Nexus, it is standardised and then 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.

The structure standardisation in Nexus 2.2 uses a set of transform rules including, but not limited to, aromaticity perception, transforming pentavalent Nitrogens and removing specific stereochemistry. The aim of the standardisation is to interpret structures more accurately, in order to optimise predictions.


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 testing 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:

  • Potential Mutagenic Impurities (PMI) Assessment and Management
  • As Part of a Defined Approach for Skin Sensitisation Assessment
  • Screening and Compound Profiling

Potential Mutagenic Impurities (PMI) Assessment and Management

Derek Nexus is widely used to assess PMIs and is used commonly within the pharmaceutical industry1 for the 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; holding a large amount of relevant data
  • Mirabilis; list the potential impurities that are unlikely to be purged during the synthetic process
  • Zeneth; list the potential degradants of the compounds involved
  • Lhasa Carcinogenicity Database; a free, online database for the retrieval of relevant carcinogenicity data
  • Setaria; search for existing knowledge across the organisation and store predictions, expert assessment and conclusions. 

Scientists use the tools in conjunction to perform read-across studies allowing users to make decisions across all available data. Read more about Derek Nexus for ICH M7 assessments.

As Part of a Defined Approach for Skin Sensitisation Assessment

There has been a significant drive to reduce, refine and replace animal models for the prediction of skin sensitisation. This is in part due to the implementation of EU regulation 1223/20092 which prohibits the sale and marketing of any cosmetics and cosmetic ingredients which have been tested on animals.

Derek Nexus predictions for skin sensitisations can be combined with in chemico/in vitro assays, in the form of a Defined Approach, to give a more accurate assessment of hazard3. Read more about Derek Nexus EC3 predictions and their use in Skin Sensitisation assessment.

Figure 1: A Defined Approach using Derek Nexus and a 2 out of 3 in silico/in chemico/in vitro method:


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 toxicity4.

2-Stage Processing (Figure 2)

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 2: 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. Furthermore, Lhasa Limited offers QMRF templates allowing for a consistent approach to reporting.



  1. 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
  2. European Union. (2013) Off. J. Eur. Union 56, 34–66
  3. Macmillan et al. (2019) 'A defined approach for predicting skin sensitisation hazard and potency based on the guided integration of in silico, in chemico and in vitro data using exclusion criteria', Regulatory Toxicology and Pharmacology, vol. 101, February, pp.35-47. https://doi.org/10.1016/j.yrtph.2018.11.001
  4. 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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