First Virtual Stomach Explores Drug Delivery

Researchers have developed the first virtual stomach, a computer-generated model that is providing unique insights into the way medicines are released from pills and capsules. “There’s no other technique to allow you to see flow patterns in a real stomach, animal or human,” said lead researcher James G. Brasseur, Ph.D., a professor of mechanical engineering and bioengineering at The Pennsylvania State University. Although pills and tablets have become a ubiquitous part of our society, the detail of how the stomach breaks them down to help release their medicine remains unclear. “You can give someone a drug and measure its uptake in tissue,” he said, “but the process between administering the drug and the uptake is largely guesswork.” From Pennsylvania State University :First Virtual Stomach Explores Drug Delivery

Researchers have developed the first virtual stomach, a computer-generated model that is providing unique insights into the way medicines are released from pills and capsules.

“There’s no other technique to allow you to see flow patterns in a real stomach, animal or human,” said lead researcher James G. Brasseur, Ph.D., a professor of mechanical engineering and bioengineering at The Pennsylvania State University.

Although pills and tablets have become a ubiquitous part of our society, the detail of how the stomach breaks them down to help release their medicine remains unclear. “You can give someone a drug and measure its uptake in tissue,” he said, “but the process between administering the drug and the uptake is largely guesswork.”

The virtual stomach has revealed a high degree of coordination between the stomach’s muscle contractions and when it releases its contents into the small intestine. A tablet’s location in the stomach – whether it floats or sinks – also greatly affects its breakdown.

“What we’ve found is that even if these tablets are slightly buoyant, it makes a big difference in how long it takes them to reach the lowest part of the stomach,” said Brasseur. Contraction waves in the lower part of the stomach break down and mix food and tablets for delivery into the small intestine, where medicines enter the bloodstream. If the tablet doesn’t’ enter the lower zone it doesn’t break down very well. “It just sits there as if it were in a glass of water,” he said.

The researchers anticipate that these and other insights from the computer model will lead to more effective oral drug delivery, shed light on certain stomach diseases, and help explain basic gastric function.

The model combines sophisticated software with a realistic model of stomach geometry derived from magnetic resonance imaging of the human stomach, which was provided by Dr. Werner Schwizer at University Hospital, Z?rich Switzerland. Anupam Pal, Ph.D., a research associate working with Brasseur at Penn State, developed the algorithm and computer simulations.

The simulations show pressures, the motion of gastric fluid, and the path and breakdown rate of tablets, revealing specific processes that lead to the release and mixing of medicine in the stomach.

“We can simulate the tablet breaking down with our new approach, watch the slow release of medication happen in a computer movie and analyze the process,” Brasseur said.

The virtual stomach simulations show three different zones: one gentle, one moderately stressful to tablets and conducive to mixing, and a third highly active zone, the target area where a tablet can break down rapidly and accelerate mixing. Buoyancy affects longer-time mixing and drug release.

Pal presented the research results at a meeting of the European Society of Neurogastroenterology and Motility in Tubingen, Germany, in October. The research team included physicians from Sweden, Switzerland and Australia.

The research is in collaboration with the group of Dr. Bertil Abrahamsson at AstraZeneca Pharmaceuticals in M?lndal Sweden, which is supporting the research. Earlier support also came from the Janssen Research Foundation.

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