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 – the specifications and quality requirements – 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 use.
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 design.
MR&P manufactures 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.