Section Three; Page 1 of 17

3DESIGN CONTROLS

Section Three; Page 1 of 17

INTRODUCTION

The Safe Medical Devices Act of 1990 added design validation requirements to the GMP requirements in section 520(f) of The Act. Section 820.30 of the Quality System (QS) regulation lists the design control requirements that manufacturers should satisfy to be in compliance. This chapter describes design controls and provides guidance to assist manufacturers in complying with design control requirements.

“Design Control Guidance for Medical Device Manufacturers” is another document that may assist manufacturers in understanding the intent of the design control requirements. This manual interprets the language of the QS regulation and explains the underlying concepts in practical terms. “Do It By Design: An Introduction to Human Factors in Medical Devices” is a document that contains background information about human factors as a discipline, describes and illustrates device problems and discusses human factors principles and methods as a part of the design control system. Both of these manuals are possible resources for manufacturers who are either developing or improving their design control system. These manuals are also available through DSMA.

Coverage

The design controls section 820.30 of the QS regulation applies to the design of products, and processes and changes to existing designs and processes. Changes to existing designs should be made in accordance with design control requirement even if the original design was not subject to these requirements. Design controls are not retroactive to completed portions of ongoing design programs.

Each manufacturer of any class III or class II device, and class I devices automated with computer software and those listed below shall establish and maintain procedures to control the design of the device in order to make certain that specified design requirements are met. Manufacturers of other Class I devices should develop and document their devices under their own design control system because the documentation is needed to help meet the device master record requirements in 820.181 and marketing submission requirements. Thus, manufacturers of exempt Class I devices are encouraged to use 820.30, Design Controls, as guidance.

Classification

Section

868.6810 Catheter, Tracheobronchial Suction

878.4460 Glove, Surgeon’s

880.6760 Restraint, Protective

892.5650 System, Applicator, Radionuclide, Manual

892.5740 Source, Radionuclide Teletherapy

All Devices automated with computer software

The design requirements for the device are primarily specified by the manufacturer; however, FDA has a few design requirements in the 21 CFR Part 801 labeling regulations and in Parts 1000-1050 which cover radiological and electronic products. A few of the FDA design requirements are in standards. For example, some parameters for medical gloves are in standards by the American Society for Testing and Materials (ASTM). (That is, medical gloves are required to meet these standards in order to be substantially equivalent to gloves already in commercial distribution.)

QUALITY SYSTEM

Each manufacturer is required to establish and maintain a quality system that is appropriate for the specific medical device(s) designed or manufactured [820.5 and 820.1(a)(3)], and that meets the requirements of Part 820. Therefore, the details of design control systems will vary depending on the complexity of the product or process being designed. However, all non-exempt manufacturers including very small manufacturers and manufacturers that design less complex devices or processes are expected to define, document and implement design control procedures and other quality system procedures as called for in the regulation. One of these, a sample design input procedure, is exhibited at the end of this chapter.

Manufacturers may establish one design control procedure to cover the various design control sections in 820.30; or, they may use one or more procedures for each topic. Multiple procedures may be easier to develop, update and implement. Medium to large manufacturers may have several additional procedures to support their main design control procedures. Design control procedures may be part of the quality system records (QSR) noted in section 820.186.

Personnel Training

Personnel training in 820.25 is one of the quality system requirements, which applies to employees that perform any activity covered by the QS regulation including all design activities.

Manufacturers are required to establish procedures for identifying training needs and making certain that all personnel are trained to adequately perform their assigned responsibilities. Design personnel shall be made aware of device defects which may occur from the improper performance of their specific jobs. In particular, personnel who perform verification and validation activities shall be made aware of defects and errors that may be encountered as part of their job functions.

Most technical employees need various degrees of training, as appropriate, in the medical device regulations, safety, labeling, human factors, verification, validation, design review techniques, etc.

DESIGN AND DEVELOPMENT PLANNING

Developing a new device and introducing it into production are very complex tasks. For many new devices and associated manufacturing processes that use software, these tasks are further complicated because of the importance of software, and the possibility of subtle software errors. Without thorough planning, program control, and design reviews, these tasks are virtually impossible to accomplish without errors or leaving important aspects undone. The planning exercise and execution of the plans are complex because of the many areas and activities that should be covered. Some of the key activities are:

ºdetermining and meeting the user/patients requirements;

ºmeeting regulations and standards;

ºdeveloping specifications for the device;

ºdeveloping, selecting and evaluating components and suppliers;

ºdeveloping and approving labels and user instructions;

ºdeveloping packaging;

ºdeveloping specifications for manufacturing processes;

ºverifying safety and performance of prototype and final devices;

ºverifying compatibility with the environment and other devices;

ºdeveloping manufacturing facilities and utilities;

ºdeveloping and validating manufacturing processes;

ºtraining employees;

ºdocumenting the details of the device design and processes; and,

ºif applicable, developing a service program.

To support thorough planning, the QS regulation requires each manufacturer to establish and maintain plans that describe or reference the design and development activities and define responsibility for implementation.

The plans should be consistent with the remainder of the design controls. For example, the design controls section of the quality system requires a design history file (DHF) [820.30(j)] that contains or references the records necessary to demonstrate that the design was developed in accordance with the:

1.approved design plan, and

2.regulatory requirements.

Thus, the design control plans should agree with, and require meeting, the quality system design control requirements. One of the first elements in each design plan should be how you plan to meet each of the design control requirements for the specific design you plan to develop; that is, the design plans should support all of the required design control activities. Such plans may reference the quality system procedures for design controls in order to reduce the amount of writing and to assure agreement.

Interface

Design And Development Planningsection 820.30(b) states:

“The plans shall identify and describe the interfaces with different groups or activities that provide, or result in, input to the design and development process...”

If a specific design requires support by contractors such as developing molds, performing a special verification test, clinical trials, etc., then such activities should be included or referenced in the plan and proactively implemented in order to meet the interface and general quality system requirements. Of course, the interface and general requirements also apply to needed interaction with manufacturing, marketing, quality assurance, servicing or other internal functions.

Proactive interface is a important aspect of concurrent engineering. Concurrent engineering is the process of concurrently, to the maximum feasible extent, developing the product and the manufacturing processes. This valuable technique for reducing problems, cost reduction and time saving cannot work without proactive interface between all involved parties throughout all stages of the development and initial production program.

Structure of Plans

Each design control plan should be broad and complete rather than detailed and complete. The plan should include all major activities and assignments such as responsibility for developing and verifying the power supplies rather than detailing responsibility for selecting the power cords, fuseholders and transformers. Broad plans are:

ºeasier to follow;

ºcontain less errors;

ºhave better agreement with the actual activities; and

ºwill require less updating than detailed plans.

Over the years, several manufacturers have failed to follow this advice and opted for writing detailed design control procedures. They reported being unable to finish writing the over-detailed procedures and were unable to implement them.

Regardless of the effort in developing plans, they usually need updating as the development activities dictate. Thus, the QS regulation requires in 820.30(a) that the plans shall be reviewed, updated, and approved as the design and development evolves. The details of updating are left to the manufacturer; however, the design review meetings are a good time and place to consider, discuss and review changes that may need to be made in the design development plan.

DESIGN INPUT

Design input means the physical and performance requirements of a device that are used as a basis for device design [820.3(f)].

Section 820.30(c) Design Input, requires that each manufacturer shall establish and maintain procedures to make certain that the design requirements relating to a device are appropriate and address the intended use of the device, including the needs of the user and patient. Also, a design requirement in 820.130 requires that each manufacturer shall make certain that device packaging and shipping containers are designed and constructed to protect the device from alteration or damage during the customary conditions of processing, storage, handling, and distribution. The intent of 820.130 is to add the broad conditions that are considered for a package design. Packaging design activities should be done according to design controls. Likewise, the design of the content and physical parameters of labeling are covered by design controls. Manufacturers that are exempt from design controls shall labeling and packaging specifications in the DMR (820.181) and are encouraged to use the QS design controls as guidance.

The input procedures shall address incomplete, ambiguous, or conflicting requirements. The design input requirements shall be documented and shall be reviewed and approved by a designated individual(s). The approval, including the date and signature of the individual(s) approving the requirements, shall be documented.

Under a design control system, manufacturers should identify device requirements during the design input phase or beginning of the design activity. Design input includes determining customer needs, expectations and requirements plus determining regulatory, standards, and other appropriate requirements. These various requirements are documented by the manufacturer in a set of device requirements. A set of design input requirements, when converted to engineering terminology, finalized and accepted as part of the device master record is called a device or product specification.

The design input phase usually is a continuum because intensive and formal input requirements activities usually occur near the beginning of the feasibility phase and continue to the early physical design activities. After the initial design input phase there are also intensive and formal activities to reduce the input requirements to engineering-type input specifications -- usually called a product or device specification.

At the opposite end of the design program, the last event is initial production which may be pilot production or the beginning of routine production. Whether a manufacturer starts with pilot or routine production depends on the nature of the new device and associated production. Pilot devices may be distributed after design validation of initial units is completed if they meet all of the device master record and other GMP requirements. Some manufacturers, however, use the pilot models in training programs for technical writers, production and service personnel, etc. Pilot models are also commonly used in early marketing displays.

After the concept of the new device design is established, the following basic design input questions should have been answered:

1.What is the real need for the new device?

2.Where will the new device be used?

3.Who will use the new device?

4.How will the new device be used?

5.With what devices will the new device be used?

6.How long will the new device be used? and

7.Other questions related to the specific device to be developed.

Designing a device and verifying that it meets customer requirements are expensive and time consuming activities. Therefore, to control these activities and increase the probability of achieving desired safety and performance characteristics, device, software, and process requirements and specifications should be thoroughly reviewed and approved before physical design and development begins. As the design evolves, the hardware, software, packaging, labeling, etc., shall be verified [820.30(f)] and reviewed [820.30(e)] versus their latest specifications to verify that design input requirements have been met.

Input Checklists

Device requirements should identify all of the desired performance, physical, safety and compatibility characteristics of the proposed device and, ultimately, the finished device. Design input also includes requirements for labeling, packaging, manufacturing, installation, maintenance and servicing. The final device specifications should cover ALL of the device characteristics. The device specifications may incorporate other specifications by reference such as reference to the manufacturer’s list of specifications for a type of device, to specific paragraphs in standards, or to all of a standard, etc. with respect to a referenced specification. It should be very clear exactly what is going to be met. A failure to properly address characteristics or factors such as immunity from transients in the power source, thermal stress, electromagnetic compatibility (EMC), packaging protection, shipping stability, proper maintenance, etc., can have disastrous consequences.

It is possible to diligently develop device requirements and still forget one or more elements in the final specification. Hopefully, no key factors will be left out. To reduce the probability of a requirement or characteristic being left out, a specification checklist(s) may be used during the design input phase. A checklist should be developed that is broad based but also germane to the product line of the manufacturer. If used, a checklist should be part of a standard operating procedure such as a Design Input Specification Procedure.

The input requirements should cover any standards that the manufacturer plans for the device to meet. In the United States, information about essentially all national and international standards may be obtained from the American National Standards Association (ANSI), 11 West 42nd Street, New York, New York, 10036, phone 212-642-4900. ANSI is a private organization, which monitors most of the standards activity in the United States and foreign activity in which U.S. citizens “officially” participate. Thus, ANSI can supply addresses and other information about all well established standards writing groups. Also, ANSI has for sale many different types of standards including quality system standards. For example, the International Electrotech Commission has a draft design review standard, “Guide on Formal Design Review” (plus a supplement), which should be helpful to product assurance/design control personnel.

The QS regulation requires that the input procedures shall address incomplete, ambiguous, or conflicting requirements. Thus, every reasonable effort should made to collect all of the requirements from which the designers can generate detailed design specifications that are clear, correct and complete.

At the end of the major aspects of the design input stage, the design input requirements shall be documented and shall be reviewed and approved by a designated individual(s). The approval, including the date and signature of the individual(s) approving the requirements, shall be documented.

A documented device specification or set of specifications derived from the input requirements should exist at the beginning of the physical design project. The device and other related specifications should be kept current as the design of the device, packaging, labeling and manufacturing processes evolve during the development program. As the physical design evolves, the specifications usually become more specific and more detailed.

The device specification will undergo changes and reviews as the device design evolves. However, one goal of market research and initial design reviews is to establish complete device requirements and specifications that will minimize subsequent changes.

Old versions of the input requirements and later the input specifications are put in the design history file (DHF) or indexed in the computer as part of the DHF to help show that the design plan was followed.

DESIGN REVIEW

Design review [820.30(e)] is one of the key design control elements in a quality system. The objectives of design review are stated in the definition of design review in 820.3(h) as follows:

Design review means a documented, comprehensive, systematic examination of a design to evaluate the adequacy of the design requirements, to evaluate the capability of the design to meet these requirements, and to identify problems.

To meet the systematic design review requirement, device design and design reviews should progress through defined and planned phases starting with the design input phase and continuing through validation of initial production units or lots. Subsequent activities are usually design changes.

To meet the design review comprehensive requirement, assessments should include a formal review of the main device and subsystems, including accessories, components, software, labeling, and packaging; production and resource needs; and installation and service, if needed. The scope includes performance, physical safety, compatibility with other devices, overall device system requirements, human factors, and environmental compatibility.