Drug absorption in the stomach affected by body posture
First-of-its-kind research using a novel silicone simulator – based on the anatomy and morphology of the stomach, has shown how body posture affects stomach motility and drug dissolution. Researchers from Johns Hopkins University (JHU) and Johns Hopkins School of Medicine have revealed that the bioavailability and efficacy of a drug depends on the stomach’s sensitive and dynamic physiological environment in addition to pharmaceutical ingredients.
Oral administration of medication is the most common and easy method of drug delivery, and is used both in clinical and home settings. Despite this, swallowing a pill or capsule is the most complex way for the human body to absorb a drug.
“When the pill reaches the stomach, the motion of the stomach walls and the flow of contents inside determine the rate at which it dissolves. The properties of the pill and the stomach contents also play a major role,” said Rajat Mittal, a professor of mechanical engineering at JHU and expert at computational fluid dynamics.
Stomach contents, motility, and gastric fluid dynamics all affect a drug’s bioavailability. At the same time, stomach contractions can induce pressure and generate complex pill trajectories as well – stomach contractions are largely influenced by body posture.
This results in varying rates of drug dissolution and nonuniform emptying of the drug into the duodenum (beginning of small intestine) and, sometimes, gastric dumping in the case of modified-release dosage.
“Current experimental or clinical procedures for assessing the dissolution of oral drugs are limited in their ability to study this, which makes it a challenge to understand how the dissolution is affected in different stomach disorders, such as gastroparesis, which slows down the emptying of the stomach – we demonstrate a novel computer simulation platform that offers the potential for overcoming these limitations,” said Prof. Mittal.
Using a biomimetic simulator called “StomachSim,” the researchers generated data that would provide critical insights into the complex physiological processes behind the oral administration of drugs.
The modelling analysed gastric biomechanics with pill movement and drug dissolution to quantify an active pharmaceutical ingredient passing through the stomach. It enabled the researchers to calculate and compare the emptying rate and the release of a dissolved active pharmaceutical ingredient for a variety of physiological situations.
