Extractable Material Characterization

USP physicochemical tests plastics USP physicochemical test panel for elastomeric closures for injections USP polyethylene containers tests heavy metals and nonvolatile residues Indirect food additives and polymers extractables (21 CFR 177) Sterilant residues ethylene oxide, ethylene chlorohydrin, ethylene glycol Metals determination by atomic absorption spectroscopy Nonroutine characterization of organic extractable material Ultraviolet visible spectroscopy

Polysulfone and Polyphenylsulfone

Polysulfone was originally developed by BP Amoco and is currently manufactured by Solvay Advanced Polymers, S.A. (Brussels, Belgium), under the trade name Udel . Polyphenylsulfone is sold under the trade name Radel . Polysulfone is a tough, rigid, high-strength transparent (light amber) thermoplastic that maintains its properties over a wide temperature range from -150 to above 300 F. Designed for use in FDA-recognized devices, it also passed all tests of the U.S. Pharmacopeia Class VI...

Finding Plastics

There are seemingly endless varieties of plastics under hundreds of trade names. A convenient way to sort through these materials is the Polymer Trade Name section of Matweb.com (http www.matweb.com search SearchTradeName.asp). This can help locate the manufacturer of a material you are interested in, as well as the composition of a trade name 8 The best starting point for understanding biocompatibility requirements is ANSI AAMI ISO Standard 10993, Biological Evaluation of Medical Devices. Part...

Cytotoxicity Tissue Culture

Cell culture assays are used to assess the biocompatibility of a material or extract through the use of isolated cells in vitro. These techniques are useful in evaluating the toxicity or irritancy potential of materials and chemicals. They provide an excellent way to screen materials prior to in vivo tests. There are three cytotoxicity tests commonly used for medical devices. The direct contact procedure is recommended for low-density materials, such as contact lens polymers. In this method, a...

Medical Teaching And Training Models

Another area of medical illustration is the production of medical models. There are numerous varieties of medical models, from the purely visual, to those for training, to those purely for engineering. Rapid prototype models have become a common tool for planning complex surgeries. Examples of these are shown in Chapter 6. Training models mimic some features of a surgical procedure, such as the retraction of tissue for an open procedure, the trackabilty of a catheter, or the insertion force of...

Interview With Thomas Fogarty Md

Fogarty, M.D., is a legend in the medical device community. He is a retired vascular surgeon, a highly regarded winemaker,1 a venture capitalist, and a leading medical technology innovator. He has founded or co-founded more than 30 companies in the medical device or services field, holds more than 100 patents, and is author of more than 170 scientific and medical articles. Dr. Fogarty invented the Fogarty embolectomy catheter while still a medical student and also developed the stent...

The Medical Illustration Bookshelf

Medical device designers can benefit from having a complete library of good anatomical reference material. The question is What is good reference material A number of years ago, the Association of Medical Illustrators22 published a suggested reference bookshelf, and some of those recommendations are reflected in this list. There is no one atlas that covers every structure in the way and in the detail you might require. It is a good idea to go to a school of medicine bookstore and look at each...

Other Ways To Tip A Catheter

In this example, a custom-made glass mold is used to form the tip. Since many of these devices were to be built, this was the best solution. However, you may find yourself at the workbench late some afternoon or evening and need to put a tip on a catheter for an in vitro prototype. What do you do then One way to make a tipping die is to fabricate one out of brass or aluminum on a lathe. Drill out a metal rod to the diameter of the catheter tube with a plus tolerance for clearance. Grind a drill...

Interview With Dane Miller

Dane Miller, Ph.D., is president and CEO of Biomet, Inc., a major force in the orthopedics marketplace. From humble beginnings in 1977, Biomet has grown into one of the most respected names in the orthopedics and medical device industries, delivering consistent year-in and year-out double-digit growth. I met with Dr. Miller for this interview at the headquarters of Biomet in Warsaw, IN. MDR& D Thank you again, Dane, for this interview. Could you describe how Biomet was founded DM Well, I...

InPrint and Online Resources

Ed Grenda is president of the Castle Island Company and publishes a free online digest of RP technology. Of special interest is a page dedicated to the medical applications of rapid prototyping. This information is well researched, updated frequently, and free. Go to to visit the medical applications section. For in-depth market and technical information on RP, Terry Wohlers publishes and sells his yearly Wohler's Report The book Automated Fabrication by Marshall Burns (Prentice Hall, Englewood...

Arm Probe Scanners

Contact probe scanners are available from Faro (Lake Mary, FL, www. faro.com), Immersion (Microscribe) (San Jose, CA, www.microscribe.com), and Romer CimCore (Farmington Hills, MI, www.cimcore.com). Arm probe scanners are a way to digitize objects with a higher degree of user control than automated scanning methods. Arm probe scanners are popular in manufacturing environments such as automotive and aerospace. Arm probe scanners can plug directly into three-dimensional surfacing programs such as...

Polyetherimide PEI Ultem PEEK Polysulfone

These materials are available in pellet form for injection molding when exceptional strength and heat resistance are required. The trade names, properties, and manufacturers of these materials are described earlier in the chapter. Keep in mind that some engineering plastics can also be quite expensive per pound of material. When designing a cost-effective disposable device, it is important not to overspecify the plastic, and have a part that is more expensive than it needs to be, but also may...

Dlp Envisiontec Perfactory

Digital light processing (DLP) is a photopolymer method to build parts. Envisiontec GmbH (Marl, Germany, www.envisiontec.de) markets this technology in its Perfactory system. In this process an entire image is projected onto the surface of a vat of photopolymer. The Perfactory lens system from Envisiontec is based on Texas Instruments DLP technology. In this method, a MEMS chip reflects an image off millions of mirrors through an optical engine into the surface of the resin to be cured. In this...