A Penn State research team may have discovered last month the reason why medications taken regularly have different activation times.

A computer model of a virtual stomach revealed a central pathway in the human stomach, which researchers dubbed the "Magenstrasse."

The discovery could explain the seemingly random lengths of time it takes for drugs to respond in the human body.

Pharmaceutical companies looking to improve reaction times could take advantage of this find if they could figure out how to change the density of the tablet so it doesn't open up right away, or even try to get it to open up in the central pathway, said James Brasseur, professor of mechanical engineering, bioengineering and mathematics. Brasseur collaborated with research associate Anupam Pal and Bertil Abrahamsson of AstraZeneca Pharmaceuticals in Sweden.

Brasseur said he had always wondered how the stomach emptied and where the fluid went after leaving the stomach. This was the question that spawned the research for the discovery, he said.

The stomach is a bag that holds 500 to 700 milliliters of liquid and solid content, Brasseur. The bottom of the stomach, produces continual, wave-like muscle contractions, he said. The contractions control the food movement in the stomach. The contractions help break down the food and mix it -- emptying the stomach becomes the central role, he said.

Using MRI imaging from human subjects to create accurate geometry of the muscle contractions, the researchers were able to see how a narrow pathway formed in the center of the stomach during the contractions, he said. The food exits the stomach more rapidly through the pathway than the regions near the walls of the stomach. "We emptied the stomach on the computer model for 10 minutes, and as fluid left the stomach, we tagged the particles," Brasseur said. "Then, we ran the simulation backwards and saw where the particles came from."

As they ran the simulation backwards, the central road appeared, he said. The particles in the virtual stomach that were on the central road exited the stomach in the 10-minute window. He said they found the Magenstrasse reached all the way from the stomach's exit up to the top portion of the stomach.

With improved models to accurately measure the material absorbed, pharmaceutical companies can improve products. "If a pill opens up in the central path, it could be out in 15 minutes, but if it opens up on the side, it can activate in minutes or an hour," he said.

AstraZeneca said that more tests are required to improve reaction times of medications. "Further improvement of it in-vivo predictive value of Biopharmaceutical tests is important for better-designed absorption of drugs, improved safety as well as improved products in the future," said a statement from AstraZeneca.