Virtual Drug Tests

Today, computer-assisted prediction models play an important role across all levels of pharmaceutical research and development at Bayer.

Using the computer to predict the physiological effect of drugs

Virtual drug tests are one example where computer software simulates the behavior of an active substance in the living organism.


In collaboration of Bayer IT specialists and drug discovery scientists two virtual drug tests were developed in-house: The PK-Sim™ simulation software predicts pharmacokinetic processes, such as the absorption, transport and metabolism of the active substance in the body. The coagulation simulator, on the other hand, simulates the effect of active ingredients on the blood-clotting process.


PK-Sim™: the active substance's route through the body


PK-Sim™ simulation software does what is known as a whole-body ADME simulation taking into account all the processes that determine the fate of an active substance in the body – from absorption to distribution, metabolism and excretion. The software makes it possible to predict which route the substance will take in the body after oral or parenteral administration, which organ will break it down, where it will act and in what concentration.


PK-Sim™ calculates the projections on the basis of a database. Specific figures on several tens of thousands of substances have been fed into it, for example on solubility, protein binding, molecular weight and excretion; it also contains data on the blood-flow rate, on volume, fat and protein content, as well as the vascular surface areas of 15 organs (including the liver, heart, kidneys, brain and bones). In addition, the program has integrated the distinguishing features of four species (mouse, rat, dog and human), so that the effect of a substance can be specifically predicted for an organism of one of these four species.


Coagulation simulator: virtually influencing blood clotting

The coagulation simulator is a pharmacodynamic computer model that shows pharmacological processes in the body in a virtual way – in this case it portrays the influence of pharmaceutical active substances on blood coagulation.


The simulation shows the complex coagulation process by which the body stops the blood flow in the event of injury: coagulation factors wash in and are activated in a cascade, the wound being closed in an interaction between platelets (thrombocytes), coagulation factors and other proteins.


On the basis of this virtual process, the scientists can now examine the effect of active substances – e.g. anticoagulants like rivaroxaban and other compounds from Bayer's research pipeline. In the course of this process they can vary all manner of parameters, such as the dose of the active ingredient, and use the computer simulation to predict how this change would affect wound closure or the risk of bleeding.


The software brings benefits on many levels

Computer-based technologies like these not only make the work of the researchers easier, they also help to further reduce the amount of animal testing needed and to make drug development more efficient, more target-focused and safer – for example in the selection of drug candidates or the planning of clinical trials.