Medical device packaging is almost as important as the device itself. Packaging for medical devices plays a key role in safely delivering specialized treatment to patients. Most single use, sterilized medical devices can be opened with a high degree of confidence that it has remained sterile throughout storage, handling, and transportation.
What makes medical device packaging doubly important is that regulatory authorities recognize the critical nature of sterile barrier or primary package by considering them components or accessories to the medical device. This implies that packaging is almost as important as the device itself.
Below are some common mistakes that companies make when developing and validating packaging systems for terminally sterilized (inside a closed package) medical devices.
- Losing sterile integrity
This is the most common defect in medical packaging and can happen from fractured thermoforms along with pinholes, slits, cuts, and tears in pouch packages. These defects come from handling (or mishandling), vibrations during transportation, storage, and impact caused by dropping.
- Cutting too many corners
Many people in medical device manufacturing are unaware of the need to test their packaging, or the existence of the ISO 11607 standards and the fact that these standards are being used by the FDA and the European Community. So they try to validate the packaging “on the cheap” without using sound, scientific practices. In their haste to get a product to market, companies risk non-compliance with regulations, or worse yet, they unknowingly risk letting suspect devices reach patients.
- Not prequalifying package and product for compatibility
A common package development mistake skips the preliminary evaluation and just dives into package validation. Cutting corners to trim time is short-sighted and usually backfires by extending development schedules and increasing overall validation costs because some part of the package fails. That means retests.
- Ignoring the worst-case scenario
To determine the worst-case scenario, it is necessary to decide the most common shipping configuration before validating the package. In this way, other package configurations of the same or similar products may be covered by one validation.
- Not developing protocols
Before working on a validation, write a protocol. It provides a blueprint for how testing will be done, including its purpose, scope, responsibilities, parameters, production equipment and settings, and acceptance test criteria. Validation qualifies the materials and processes that make the complete package. If one process is not right, the entire system breaks down and the manufacturer risks harm to patients.
- Having the wrong sample size
Determining the right sample size for testing can be challenging. Many factors play a role in determining sample size including what type of test it is (e.g. quantitative/variables or qualitative/attributes); what is the sample population; how many samples are available for testing; what are the economics; and what are the risk factors (e.g. confidence intervals). The most common mistake is choosing a sample size that is too small and that renders results with no statistical significance.
- Using the wrong package type/material
Using the wrong package type or material for the product is a package-product compatibility issue, which could have been avoided if pre-qualification of the packaging had been done at an early stage. Some of the typical observations that are prevalent include fracturing of thermoform trays as a result of using the wrong plastic material for the intended product (for instance, if the product mass is too great for the impact resistance of plastic).This can be avoided for large, massive products by using a high-impact resistant plastic, such as polycarbonate, to reduce the possibility of fracturing during normal distribution and handling. The thermoform design is also critical to ensure that the product is held in place firmly so that a loose product is not jettisoned through the tray lid and fracturing of the plastic doesn’t occur from the inside-out.
- Squeezing oversized pouches into cartons
Pinhole defects in pouches can be reduced by inserting the pouch into a carton without folding, wrinkling or creasing the ends. Pinholes occur at the junctures of the creases and folds when they are vibrated, causing the intersection to be ‘worked’ or fatigued at the juncture. This effect is exacerbated by making complex folds of the pouch causing a very concentrated point of stress at the juncture of the materials. This can be circumvented by using secondary packages (cartons/shelf boxes) that are large enough to allow insertion of the pouch without folding.
- Not recognizing Tyvek® separation as a false-positive
One phenomenon that was discovered some years ago, but only really came to light when medical device packages began to be integrity tested routinely using bubble and dye-leak methods, was ‘sheet separation’ of the porous web of Tyvek®. In integrity tests, this ‘sheet separation’ appears as false-positive when the material is bent, folded, or wrinkled.DuPont has proven that this phenomenon does not change the sterile barrier performance of the material and that any leakage of air or dye solution is only along the transverse direction of the material and not between the Tyvek® and poly material, as would be the case in an adhesive (seal) failure. There is no loss of filtration capability when this occurs.However, when performing these tests, it is incumbent upon the tester to analyze the failure carefully. In some cases, when there is a suspect ‘false-positive,’ it may be necessary to look at it under high magnification to determine the cause of the leakage.
- Performing accelerated aging at high test temperature
In ill-conceived attempts to reduce costs and time, some manufacturers decide to accelerate the shelf life or expiration date studies to unrealistic and indefensible limits, usually by raising the test temperature to a level that causes packages to melt down, warp, or change in other uncharacteristic behaviors. In addition, temperatures over 65°C are indefensible based on the rationale typically used to justify accelerated aging protocols.Temperature selection for the accelerated aging study should avoid unrealistic failure conditions, such as deformation due to melting. This advice is sometimes ignored in the haste to bring products to market faster.
As critical as packaging is, some companies occasionally don’t take it seriously, considering it too late in the design cycle, cutting corners, or using inappropriate materials. Avoid these above mistakes and plan well in advance to develop and validate your packaging.