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09. January 2020

RFP Rubber Fibres Plastics, current issue:
New VDI guideline 2017 Medical Grade Plastics

Safety for patient and user is an essential requirement for medical products, in-vitro diagnostics and pharmaceutical packaging. Subsequently, plastics grades used in medical have to fulfil particular requirements, i.e. constant properties, formulation lock or biocompatibility. Surprisingly, no standard has existed to define the requirements for medical grades so far. This gap has been filled recently by the new guideline VDI 2017 developed and launched by a work group of the German Engineer’s Society (VDI). This article addresses the development of the new guideline VDI 2017 “medical grade plastics” and presents the essential requirements to be covered by medical grade plastics (MGP).

Central venous catheter made from TPU

Central venous catheter made from TPU

S. Roth
RFP Rubber Fibres Plastics 04|2019

Since neither user nor patient must subjected to any risk by a medical product, highest attention has to be paid to safe design of medical products. Therefore, legislation frameworks have been established in most countries. All these legislative works have in its common sense to reduce the risk to patient and user to a level as low as possible. Maintaining stable and consistent product requirements over lifetime of the product are regarded as core characteristic of medical products to guarantee stability in quality of product with the purpose of products safety for patients.

Consequently, stable process and hence stable material properties are essential musts for achieving stability in product properties. Extensive efforts have to be spent during the development process on validation of product and process. For instance, for medical disposables, to ensure that product properties remain constant during lifetime it is necessary to verify the product properties also after physical ageing of the product. In addition, the production process has to be validated within its boundaries of the process window to be set before validation.

Clinical evaluation of the product with respect to proof therapeutic use complete the validation process and hence the product development which can take four to eight years. It is followed by long-term lasting market phase of the product. Medical devices can be present and sold in the market nearly up to 20 years without hardly any change in design, process and material. Thus, selection of appropriate material for products in medical application at the very beginning of the development process is regarded as one of the most crucial points in the development process. Therefore, materials for medical have to meet design needs such as mechanical, thermal and chemical requirements as well as special demands to biocompatibility, Furthermore, the safety of long term supply is of importance for the long-term market phase.

All along its work, the committee has born in mind to establish a widely accepted standard that can act as a guideline for material suppliers as well as material customers. It should describe the standard and basic requirements a medical grade is expected to bring with it when declared as intended to be applied for medical application. On the one hand customers get information what to expect, on the other hand the guideline informs material suppliers about the requirements which have to be met by their materials. Since this guideline has the intention to cover a broad range of products and applications from pharmaceutical packaging, in-vitro diagnostics up to medical devices from low to high risk classification, it follows the principle to bring all requirements for a medical grade down to the least common denominator which specifies the base in specification applied to the medical grade covering all fields described.

Started by presentation of the green print, the guideline has gained acceptance by affected parties and stakeholders already. The feedback from the industry has been positive so far. Especially the character of the guideline to define and describe the basic requirements that has to be addressed between supplier and customer for medical grade plastics has been highly appraised. This gives rise to the conclusion that the guideline is accepted and used in daily practise by all stakeholders.

For future prospect, it seems to be likely that other industries also dealing with high risk applications, e.g. aeronautics or automotive, may adopt this given standard now, since they also require constant material properties for safe products providing constant and safe performance. Hence, this guideline will act as a pacemaker in regulation for plastic materials in all fields of industry that require high safety standards.

The makers of the guideline are looking forward to receiving further feedback to the guideline and how its idea will prove itself. It is planned to have a first revision already after two years in order to keep the guideline up-to-date. Finally, the new guideline VDI 2017 Medical Grade Plastics provides clarity for the description of requirements and helps to set the base for safe products from material with stable, clearly defined properties.

S. Roth, RFP Rubber Fibres Plastics, 04 2019, 239-243.


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