A redesign of a needle-free insulin injector reduced part
count and in the process also eliminated a lubrication problem and simplified
the supply chain.
"The main design challenge was learning everything about
each of the 30 plus components â the specifications and quality requirements â
that make up a completed Medi-Jector VISION," says Harlow Thielke, a quality
engineer at Minnesota Rubber and Plastics, which took over the project, replacing
15 to 20 vendors supplying 39 different components.
Developed by Antares Pharma, Inc., the injector evolved
through seven major redesigns over a 20-year period, so managing vendor
relationships had been an ongoing challenge. Antares Pharma wanted to partner
with a single manufacturer, and Minnesota Rubber and Plastics was chosen.
The Medi-Jector utilizes a spring to push insulin through a
micro-fine opening in the tip of a needle free syringe. A fine liquid stream of
correctly metered insulin penetrates the skin instantly without using a needle.
According to Thielke, the design drivers were comfort, convenience and ease of
The earliest version of the Medi-Jector was made of machined
metal components and was twice the size of the new design. In addition to its
heaviness, the device was difficult to
lubricate and keep clean after repeated use. The current version eliminates the
lubrication problem, reduces size and weight, and enhanced product function
with medical grade plastic. Use of injection molding allowed more freedom into the
and assembles medical devices in Class 10,000 and Class 100,000 clean
rooms. Device designs include seals that isolate fluids, internal bosses for
aligning actuating mechanisms containing washers and springs, and snap-fit
designs that lock the assembly together without the use of adhesives.
Antares, which is based in Ewing, NJ,
estimates the market for reusable, needle-free injectors at more than $1
billion. Its Parenteral Medicines (device) division is located in Minneapolis, MN.
Antares pioneered the development of needle-free injection systems for
individual use in 1979 and remains among the industry leaders.