Simulations Plus Releases QMPRPlus Version 5.0; Prediction of Multiple Ionization Constants and First Toxicity Model are Breakthroughs.

LANCASTER, Calif. -- Simulations Plus, Inc. (AMEX:SLP), the leading provider of ADME absorption simulation and neural net structure-to-property prediction software for pharmaceutical discovery and development, today announced the release of version 5.0 of its QMPRPlus(TM) software that predicts important properties of new potential drug molecules just from their structure.

Dr. Michael Bolger, director of life sciences for Simulations Plus, noted: "Computational chemists can create virtual libraries of millions of new potential drug molecules in the computer, but then the chemist needs a way to reduce the number of molecules down to something manageable for actual synthesis and testing. The ability to predict critical properties of a molecule from just its structure is the key to extremely high throughput in silico (in the computer) screening. In silico screening is the fastest and least expensive method to eliminate huge numbers of compounds that are doomed to fail and to identify those with the highest probability of successful development."

Walt Woltosz, chairman and chief executive officer of Simulations Plus, added: "Finding a needle in a haystack is a lot easier if you have a really powerful magnet. QMPRPlus 5.0 is such a magnet. And it comes at a time when the pharmaceutical industry is adopting new predictive tools at an accelerating rate. The FDA released a white paper in March entitled 'Innovation or Stagnation, Challenge and Opportunity on the Critical Path to New Medical Products.' In it, the FDA writes, '... a new product development toolkit -- containing powerful new ... methods such as ... computer-based predictive models ... is urgently needed.' The FDA continues, 'The medical product development process is no longer able to keep pace with basic scientific innovation. Only a concerted effort to apply the new biomedical science to medical product development will succeed in modernizing the critical path.' Simulations Plus is focused on contributing to the advancement of simulation and modeling in pharmaceutical research. Our customers want more integrated applications to reduce the number of different programs they have to run to obtain the information they need. This release of QMPRPlus 5.0 now integrates predictions for all of the most critical properties affecting oral absorption with our first toxicity model as well. We believe this is a major step toward providing integrated, high quality predictive models at an affordable price."

Dr. Robert Fraczkiewicz, senior scientist and product manager for QMPRPlus, commented: "QMPRPlus 5.0 provides two new important predictive capabilities: prediction of multiple ionization constants (pKa's) for molecules that have multiple ionizable atoms, and prediction of the potential for toxicity based on inhibition of estrogen binding to the estrogen receptor. The ability to predict multiple ionization constants is critical to understanding how certain properties change with acidity (pH) in the gastrointestinal tract. Molecules that are ionizable experience large changes in some of their critical properties when pH changes. In the stomach, pH is typically about 2, but in the small intestine and colon, the pH is much higher -- up to about 8. By knowing the ionization constants, we can calculate the percent of ionized and un-ionized forms of a molecule at any pH. This is an essential piece of information for predicting the amount of a dose that will be absorbed. There are few commercial predictive models of pKa in the world and we are proud to be part of this league after a long sustained research effort.

"Our approach to this prediction sets QMPRPlus apart because it exactly represents the thermodynamics of ionization and utilizes artificial neural network ensembles in an original way. The prediction engine was constructed with the aid of technology similar to the one utilized in our powerful QMPRchitect(TM) model building software and is fueled by a unique collection of proprietary atomic descriptors. In addition, because of the more accurate ionization predictions, we have now retrained all the existing predictive models using QMPRchitect, with improved accuracy across the board."

About Simulations Plus, Inc.

Simulations Plus, Inc., is a premier developer of groundbreaking drug discovery and development simulation software, which is licensed to and used in the conduct of drug research by major pharmaceutical and biotechnology companies worldwide. The Company has two other businesses, Words+, Inc. and FutureLab(TM), which are based on its proprietary software technologies. For more information, visit our Web site at www.simulations-plus.com.

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