Medical device design

In recent years the trend for software to be moved to mobile platforms has opened up opportunities for commodity applications which monitor our well-being and provide health advice. Many hundreds of these now exist and range from carefully designed medical devices capable of monitoring complex medical conditions to poorly crafted programs offering little more than quackery. 

Design, Medical Device and Diagnostic Industry, October 2000. 

Maddox, M. E., Designing Medical Devices to Minimize Human Error, Medical Device Diagnostic Industry Magazine, Vol. 19, No. 5,1997, pp. 166-180. 

Haut, D. Success by Design. Medical Device Diagnostic Industry, pp. 48-60, Sept. 1988. 

AH implantable medical devices ate complex in design, materials, and implementation procedures. The biocompatibiUty, biodurabiUty, and efficacy of medical devices are the subject of extensive research by biomaterials scientists, device manufacturers, and health care professionals. 

With new plastics and processing techniques always becoming available, the design challenge becomes easier, even when taking today s solid-waste problem into account. Today s plastics and processes allow designers to incorporate and interrelate all the aspects of success. In products such as electronics, medical devices, transportation controls, and many others where user-friendly design is required, it has to be obvious to all that plastics play an important role. 

The Quality System Regulation is introduced for medical devices, requiring developers of high-risk devices to apply design controls. 

FDA Design Control Guidance for Medical Device Manufacturers www.fda.gov. 

The previous chapter outlined how device classification and the use of standards provide the basis for effective regulation of medical devices, with particular focus on the application of design control standards to the development of devices. In this chapter we look at the process for evaluation and authorisation of devices, and see how the regulatory requirements vary depending on the perceived risk of the device as indicated by its classification. It will be noted that there is considerable variation between the approaches adopted in Europe and the US and that, compared to dmgs, practical harmonisation of requirements still remains to be adopted. 

The relationship between the main subsystems and other minor systems is illustrated schematically in Figure 12.4. This places management at the core of the quality system, with the other systems arranged as major and minor satellites that revolve around it. This perspective provides the basis for the Quality System Inspection Technique (QSIT), which the FDA uses for auditing medical device facilities. This is based on a top-down approach, which starts with management controls and then looks at three other key subsystems of Design Controls, Corrective and Preventative Actions (CAPA) and Production and Process Controls. The belief is that by focussing on just these four subsystems, you will actually touch on all the other subsystems and obtain a sufficiently satisfactory overview of the state of compliance of the facility. 

In pharmaceutical and medical device development, clinical trials are classified into four main phases designated with Roman numerals 1,11, III and lY The various phases of development trials differ in purpose, length and number of subjects involved. Phase I trials are conducted to determine safe dose levels of a medication, treatment or product (National Institutes of Health, 2002). The main purpose is often to determine an acceptable single dosage - how much can be given without causing serious side-effects. Phase I trials will also involve studies of metabolism and bioavailabity (Pocock, 1983). The sample size of a Phase 1 clinical trial is usually small, ranging from 10-80 subjects (National Institutes of Health, 2002 Pocock, 1983). 

The final consideration, but by no means a minor one, is the design and evaluation of contact lens care products, which are regulated by the U.S. Food and Drug Administration (FDA) as medical devices since... 

Packaging of pharmaceutical dosage forms and medical devices have many requirements in common with other commercial products. Package design must address the finished products needs, including ... 

However, it has to be realized that biological templates remain inserted in the final nanoparticles and this is not acceptable for many applications. Nevertheless, some recent examples indicate that such biomimetic materials may be suitable for the design of biotechnological and medical devices [32]. For instance, it was shown that silica gels formed in the presence of p-R5 were excellent host matrices for enzyme encapsulation [33]. In parallel, biopolymer/silica hybrid macro-, micro- and nanocapsules were recently obtained via biomimetic routes and these exhibit promising properties for the design of drug delivery materials (see Section 3.1.1) [34,35],... 

Conk, G.W., "The True Test Alternative Safer Designs for Drugs and Medical Devices in a Patent-Constrained Market," UCLA L. Rev., 49, 737 (1990). 

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