Study of the pH profile in the human gastrointestinal tract, using an ingestible electronic device: the iPill

Traditionally, the design of drugs for enteral delivery is based on chemical
characteristics that determine the site of absorption. For example drugs that
require absorption in the small bowel may have a coating that helps the drug to
pass the stomach without being changed or absorbed. However, highly predictable
delivery and exact dosing of drugs at specific sites in the gastrointestinal
(GI) tract is difficult to accomplish with the present drug delivery systems.
The iPill is a newly designed remotely monitored and controlled experimental
electronic drug delivery device that may release the contents of a container
into the gastrointestinal lumen at a location, based on information about
changes of the intraluminal pH. Intraluminal pH follows a characteristic
pattern. In the mouth and esophagus the pH is about neutral. In the stomach the
pH is low because of the secretion of gastric acid. Upon passage through the
pylorus the pH rises sharply because of the supply of bile and pancreatic juice
in duodenum. From jejunum to distal ileum the pH rises slowly to about pH
7-7.5. In the colon the pH is somewhat lower. During passage through the
ileo-cecal valve a drop of 1-1.5 pH is measured. By measuring pH, two marker
points in the GI tract can be detected, namely the pylorus and the ileo-cecal
valve. The residence time and drift velocity of larger particles is about
constant (residence time 4-5 hours, drift velocity about 1 m/hour). In between
the marker points the position of a device in the small intestines can be
translated in time. E.g. two hours after a sharp rise in pH means 2 m from the
pylorus.
The iPill system consists of an ingestible electronic device, a portable unit,
a start-up unit and software. The iPill has three functions:
1. measuring pH and temperature in the lumen,
2. wireless two way communication in order to transmit the measured data to the
outside world and to receive commands and
3. dispensing medication at a predefined location in the gut.
The portable unit relays wireless the information from the iPill to a control
station and from the control station to the iPill. The software installed on
the control station makes it possible to read out real time the measured data
on pH and temperature and to control the medication dispensing of the iPill.
The iPill will be delivered in two parts, namely an electromechanical part and
the medication container. Prior to use these two parts are clicked together and
after that ready for use.

To study in healthy human volunteers safety of the iPill system. Secondary
objectives are recording of pH and temperature of the gastrointestinal tract.
To investigate the measurement and communication functionality of the iPill
system

Observational study

The study requires ingestion of the iPill after an overnight fast and wearing a
belt with a data recorder and relay unit for 26 hours. Volunteers need to come
to the study centre for a screening visit, at T=0 for ingestion of the iPill
(total stay: 10 hours) and at T=26 hours. Volunteers are asked to retrieve the
iPill after excretion in the stool. If they haven*t retrieved the iPill at the
26 hours visit, they should come back once more to return the retrieved iPill.
Similarly sized pills have been shown to have an extremely low risk of
retention in the gastrointestinal tract. No other risks are anticipated.