MDTmag.com 20 / July/August 2014
By Forrest Payne, Ph.D., Senior Scientist,
SFC Fluidics Inc.
SFC Fluidics is developing a wearable drug delivery device targeted for more convenient and low-cost delivery of
insulin for patients who inject multiple times
per day. The current management of diabetes
can be viewed as bothersome as it requires
the patient to keep a source of supplies with
them at all times. Further, at certain times
during the day, patients must repeat the process of placing insulin into a syringe and then
This process is both inconvenient and
limits the patient’s ability to be discreet. SFC
Fluidics has been working on technology that
automates as much of the process as possible
while keeping the patient’s lifestyle in mind.
The current challenges include making a
pump small enough to wear under an individual’s clothing while also being a reliable
medical device that delivers insulin.
The first challenge that SFC overcame was
developing a non-mechanical pump. SFC
Fluidics’ ePump technology is a patented
electro-chemiosmotic means for precisely
moving fluid without any mechanical parts.
Application of a low voltage (≤1.5V) drives a
pumping fluid across a selective membrane.
This, in turn, causes an elastic diaphragm
to expand and push a controlled amount of
fluid, insulin in this case, to the patient. Reversing the direction of the voltage reverses
Technology Allows Precise
Miniaturized Drug Delivery
Developing an insulin-delivery technology that comes in a discreet package and suits the needs of diabetics
can offer an array of design challenges. In this article, a company shares its experiences and obstacles to suc-
cess while in the midst of the device’s evolution. They are presented so that other drug delivery device OEMs
may hopefully avoid them.
the direction of fluid flow. The result is very
precise flow from a reciprocating pump
that can be tailored to fit any application by
allowing virtually unlimited freedom in size
and shape design. This pump mechanism
has demonstrated that it provides reliable,
The subsequent challenges were to miniaturize the pump engine – including pump,
valves, and control system – to fit within the
discreet insulin delivery pod, and to design
the parts in such a way that they can reliably
and inexpensively be manufactured and
assembled in large quantities.
The primary challenge for miniaturization
of the pump engine was to balance the size
of the pump with the requirement to deliver
insulin into the patient in a clinically useful
timeframe. While the ePump technology
allows unlimited design freedom in the
pump geometry, the maximum pumping rate
scales with the active area of the selective
membrane and, to some extent, the overall
Figure 1: The pump engine housing contains the pump and valves and fits in a
footprint that is 25 × 50mm.
Another challenge is that
the reciprocating nature
of this miniature pump
requires external valves to
deliver fluid directionally.