Page 222 - Biomedical Engineering and Design Handbook Volume 2, Applications

STERILE MEDICAL DEVICE PACKAGE DEVELOPMENT 201

of the package seal. Under unrestrained conditions the stress on the package is highest at the middle of the
pouch where it inflates to the package’s maximum diameter; therefore, Test Methods F 1140 may not reli-
ably detect the weakest area of the seal.
The “Significance and Use” section of the standard describes how and why the standard is used and
says:
The burst test internally and increasingly pressurizes a package until an area of the package seal
around the perimeter “bursts” open in response to pressurization. By placing the package within
restraining plates during pressurization, the dimensional stability of the package is maintained in a
manner that results in stresses applied more uniformly along the perimeter of the package, where seals
are normally placed. This allows the test to have a higher probability of detecting the weakest area of
the seal and provides a measurement of the pressure required to “burst” open the package. This test
provides a rapid means of evaluating tendencies for package seal failure when the package is exposed
to a pressure differential. Pressure differentials may occur during such processes as sterilization and
transportation. This test method provides an indicator of the burst strength of a package, where the
burst will normally occur in one or more areas of the seal. An indicator of the minimum burst strength
may be of importance to the package manufacturer and end user in ensuring adequate package
integrity. This test method cannot provide a measure of package seal uniformity. This test method also
cannot provide an evaluation of overall package integrity or the burst strength of areas of the package
that contact the surface of the restraining plates used. This test method should be combined with other
methods of evaluating overall package integrity, uniformity of the package seal, or opening function-
ality, if so required.
This test frequently is used to quickly evaluate package seal strength during the manufacturing
process and at various stages of the package life cycle.
If correlations between pieces of test equipment are to be made, it is important that all parameters of
the test be equivalent. Typical parameters can include, but are not limited to, the package size, material,
type and configuration of seal, rate of air flow into the package, pressure detection sensing mechanism
and sensitivity (machine response to pressure drop), position of test article, rigidity of restraining plates,
and distance between restraining plates.
This test may not necessarily provide correlation with package seal strength as typically measured
using Test Methods F 1140 or F 88 (or equivalents).

7.6.4 Package “Conditioning”Tests
When we use the term “conditioning” we are referring to any type of situation that exposes the pack-
age to hazards inherent in the life cycle of the package, including shelf life (aging), environmental
(temperature and humidity, atmospheric pressure), and dynamics (shock and vibration). These tests
do not produce a test result per se, but subject the packages to conditions that may compromise the
package system. Consequently, they are not required to be validated, but should represent the best or
most realistic simulation of the conditions inherent in the package life cycle. Several guidelines and
practices have been developed to provide a standardized means of subjecting packages to condition-
ing prior to package integrity testing. More detail will be provided in later sections of this chapter;
however, the conditioning standards of interest are
• D4169-05 Standard Practice for Performance Testing of Shipping Containers and Systems
• D4332-01(2006) Standard Practice for Conditioning Containers, Packages, or Packaging
Components for Testing
• D6653-01(2006) Standard Test Methods for Determining the Effects of High Altitude on
Packaging Systems by Vacuum Method
• D7386-08 Standard Practice for Performance Testing of Packages for Single Parcel Delivery
Systems
• E171-94(2007) Standard Specification for Standard Atmospheres for Conditioning and Testing
Flexible Barrier Materials
• F1980-07 Standard Guide for Accelerated Aging of Sterile Barrier Systems for Medical Devices