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Overview of Updated ASTM F88/F88M – 23

ASTM F88/88M, the standard test method for assessing the seal strength of flexible barrier materials was recently updated.  

In previous revisions, Techniques A, B, and C in the standard offered clear testing instructions for flexible-to-flexible or semi-rigid packages (such as pouches), but it lacked clear guidance on conducting tests for trays made of flexible-to-rigid or semi-rigid materials.

The latest revision ASTM F88/F88M-23 has rectified this gap by providing users with guidance on conducting seal strength testing for trays. Two approaches relevant to trays have been incorporated into Technique C, offering users options to determine the most suitable method for testing their packages.

For further detail on this update, please see our recent video with DDL’s Lab Supervisor Kevin Rardon demonstrating Technique C performed on trays, along with Technique A and Technique C with pouches.

DDL has extensive experience conducting seal strength testing on trays. Historically, our approach involved following the flexible-to-intact rigid or semi-rigid structure method, and this approach will remain consistent in our future testing procedures.

Furthermore, we have carried out Test Method Validation (TMV) across all DDL locations based on this approach. This validation process further ensures the reliability and consistency of our testing method, providing added confidence in its repeatability and reproducibility.

In addition to the changes on the testing of trays, the new revision also provided updated information on:

  • Flexible to flexible ILS background, rationale, and analysis  in Appendix X1
  • Flexible to Rigid ILS background, rational, and analysis in Appendix X2
  • Impact of variation in sample width and separation speed in Appendix X3
  • Optional test fixtures in Appendix X4

Please contact us for more information on Seal Strength testing or if you need help on an upcoming test.

ASTM D4169-23e1 Unpacking the Changes

This revision brings about changes primarily to compression testing, and the definition of small and lightweight packages and when to use height stack values. In this blog post, we will examine the key modifications introduced in the latest revision.

Clarification in Section 3
One of the notable changes outlined in Section 3, specifically in Sub-section 3.2.7, where a new definition for “Small and Lightweight Package” is introduced. This definition, encompassing packages weighing under 10 lbs (4.53 kgs) with a volume below 2.0 ft³ (0.056 m³), aims to provide guidance when determining the maximum stack height (H) factor. Section 3.2.7 was intended to replace Note 3 in ASTM D4169-22.

Update: Paragraph two of Section 11.4.2 was intended to replace Note 3 in section 11.4 of ASTM D4169-22. However, Note 3 was inadvertently left in the ASTM D4169-23 publication, which has led to user confusion. This change along with several other minor editorial changes were identified during a subsequent review and have been rectified in the publication of ASTM D4169-23e1, which was released on March 27, 2024.

Conditioning Standards Enhancement in Section 6
The entire ASTM D4169-23e1 standard sees an added reference to ASTM F2825 – Standard Practice for Climatic Stressing of Packaging Systems for Single Parcel Delivery. Under Section 6 Conditioning, this reference suggests that when testing is conducted using DC-13, the F2825 environmental conditioning may also be applicable, particularly for expedited shipments. This addition acknowledges the importance of testing under conditions that reflect real-world temperature variations, providing a more realistic assessment of packaging system performance.

Streamlining Warehouse and Vehicle Stacking in Section 11
Section 11 includes notable changes in Schedule B (Warehouse Stacking) and Schedule C (Vehicle Stacking). Type 4 for Shipping Unit Construction has been removed for redundancy. The introduction of a Shipping Density Factor (Mf) range, along with an increased default value, directly impacts the theoretical target load force applied to packages during compression.

Noteworthy changes in 11.4.1 suggest varying shipping density factors for mixed load and LTL shipments. The implications of these changes can be observed in real-world examples, highlighting how the revised standard can lead to higher vehicle stacking top loads.

Section 11.4.2 was added to clarify when the user may consider reducing H from the recommended default height of 108 inches. FIG. 2 Maximum Stack Height (H) Decision Matrix should be used to determine that height. Paragraph two of Section 11.4.2 was also intended to replace a portion of Note 3 in ASTM D4169-22 (see above).

Enhancements in Section 12 – Stacked Vibration
Section 12, specifically Schedule D – Stacked Vibration, contains an update in the recommended shipping density (M), increasing it from 10 to 12. This adjustment aligns with the industry’s continuous pursuit of ensuring packaging resilience in diverse environmental conditions.

If you have any questions about the recently updated ASTM D4169 standard, or need help with an upcoming test, please don’t hesitate to contact us, or call us at 800-229-4235.

ASTM F1929 Dye Penetration Integrity Test

ASTM F1929 “Standard Test Method for Detecting Seal Leaks in Porous Medical Packaging by Dye Penetration” is a dye penetration package integrity test used by package engineers that is designed to detect and locate leaks caused by channels formed between a transparent film and a porous material.

The ASTM F1929 standard was first written in 1998, was reapproved in 2004, and then ASTM made a significant update to it in 2012. In 2015, the standard was updated with no significant changes. The standard was recently updated in December of 2023. The notable change in the newly revised standard is the allowed use of alternative surfactants other than Triton X-100 as the surfactant component in the dye solution.

DDL still receives many questions about ASTM F1929. Here is a quick overview of the changes over the years:

ASTM F1929-98 (2004)

  • Utilized injection method. Observe the package for any leaks originating from the inside edge of the package seal towards the outside edge of the package seal.
  • Observe each seal for a recommended duration of 5 to 20 seconds.

ASTM F1929-12  

  • Three test methods are now called out:
    • Test Method A: Injection method (same method used from previous ASTM F1929-98 (2004). Inject dye solution within the sealed package and observe for leaks, originating from the inside edge of the package seal towards/through the outside edge of the package seal.
    • Test Method B: Edge dip method. Dip the outer edge of the package seal evenly within the dye solution and observe for leaks, originating from the ouside edge of the package seal towards/through the inside edge of the package seal.
    • Test Method C: Eyedropper method. Note: The Eyedropper method requires the packages to have an unsealed area that extends beyond the outer edge of the seal. Along the extended unsealed area (beyond outer seal edge), the transparent material is separated from the porous material (with use of a finger, paperclip, etc.). Most commonly, an eyedropper or pipette is used to apply the dye penetration solution between the transparent and porous materials of the unsealed area. Place a bead of solution between the two materials along the outer edge of the package seal, ensuring the entire outer edge of the seal is wetted with the dye solution. The package is then observed for leak,originating from the outside edge of the package seal towards/through the inside edge of the package seal.
  • As a guide, each Test Method above recommends observing each seal for a maximum of 5 seconds on a 4-sided package (20 seconds total).
  • If a channel is present in the seal, the location should be accentuated by the wicking of the porous substrate/material around the channel.

ASTM F1929-15

  • No significant changes.

ASTM F1929-23

  • The use of alternative surfactants other than Triton X-100 as the surfactant component in the dye solution is now allowed. These alternatives must adhere to the specified requirements:
    • The surfactant should be nonionic.
    • The chemical properties should align with a surface tension ranging from 30 mN/m to 33 mN/m, a hydrophilic/lipophilic balance (HLB) exceeding 10, and a critical micelle concentration (cmc) below 2000 ppm.

The ASTM F1929 is currently a recognized consensus standard by the FDA. Please keep this in mind when developing your studies and validations.

Please contact us with any questions you may have about ASTM F1929, or if we can help you with any other testing questions or projects.

Common Mistakes that Can Lead to Failures During Your Package Validation

At DDL, we do a lot of testing. We see many successful medical device package validations, but we do sometimes encounter the dreaded “failure” in a client’s validation.

Ali Payton, DDL packaging engineer, sat down with Scott Levy, DDL senior packaging engineer, to wrap up a two part video series to discuss some of the most common mistakes DDL regularly encounters with its clients regarding sterile packaging that can lead to failures during a package validation.

We hope that you will be able to take some valuable information away from this session and apply it in your own organization.

Materials

Q:  What are some considerations clients should take when selecting materials for their sterile barrier system?

A:   Understanding the product’s weight and geometry is key to this selection. In most instances, pouches tend to be more convenient as suppliers can typically get medical device manufacturers access to pouches quickly whereas trays tend to require more steps due to the formation of the cavity and sealant. Thus, many engineers try to use a pouch for heavier products and hope for the best. If you have a multi-material product with a lot of sharp edges or points, or a product with a lot of mass, you will likely want to go with a tray in this case.

For most companies, it comes down to speed in terms of getting their product to market. Thus, the more understanding upfront of what type of package configuration will work best for a product will help prevent failures down the road.

Process Validation

Q: What are some common mistakes DDL sees during the Process Validation?

A:   Building a good process validation for your package validation is like building a new house; you need a solid foundation in order to build from it.

Some common mistakes DDL sees in the process validation include issues with over sealing, under sealing and general lack of understanding the actual processing parameters or strength levels. Stepping through the process validation is critical to having a successful package validation because if a failure arises, the more questions that can be answered from your process validation will only help prevent rework loops.

Understanding what the low and high ends are of your processing window is key and critical. If you are sealing at nominal every day and you encounter over sealed or under sealed packages, then it is obvious the sealer is not staying within tolerance.

Another important aspect of process validation is inspecting the seals, particularly after it has gone through sterilization, to make sure the seals have not experienced any adverse effects in sterilization.

Shipping Configuration

Q:   What are some common mistakes DDL sees with shipping configurations?

A:   Shipping configuration is paramount to a successful packaging system, as quite a few issues can be solved by simply implementing a better package shipment orientation. For example, if you are dealing with a heavy product, ideally the packages should be bottom oriented.

A failure mechanism DDL sees quite a bit is due to abrasion. When sterile packaging is put into corrugated shippers without shelf cartons this can lead to this type of failure. As corrugated packaging is nothing more than sandpaper. If you have too many packages inside the shipper, the sterile packages will rub against the corrugate and potentially cause holes due to abrasion, or you may find failures from the packages too closely packed and rubbing against each other causing abrasion.

Lastly, the use of shelf-cartons in your shipping configuration is critical, as they offer the most protection and will give you the best chance of passing a shipping validation. The make-up of the product should dictate the type of packaging being used. For instance, placing a multi-port product in a pouch and placing five to ten of these pouches in a corrugated shipper without shelf boxes may potentially cause a number of issues. You also want to avoid folding, bending, or creasing Tyvek pouches.

Compression & Distribution Testing

Q:   DDL receives many questions on “failing” transportation simulation, specifically regarding ASTM D4169 DC 13. When a packaging system is not meeting the calculated load – what does this mean?

A:   One of the biggest failure aspects DDL sees with shipping validations is compression. Within ASTM D4169 DC 13, the standard height utilized for the compression calculation is 108” and based upon that height, there is quite a large compressive load that comes down onto the packaging system. Many of DDL’s clients are concerned when they do not meet that specific calculated load, however it is not truly a failure as the test itself is a conditioning test that is simply telling you how much compression that box can withstand. Many of DDL’s customers prefer to use 54” instead of 108” for the stack height because the overall compression force is less. It is acceptable to use 54” if the products are being sent in a “Less than Truckload” (LTL) environment, but this is not the case if the products are being sent “Full Truckload” (FTL) per how the standard is written.

Another common distribution failure is regarding concentrated impacts within Schedule J of ASTM D4169. Ideally, every medical device manufacturer should have a single wall box that is at least 44 “Edge Crush Test”(ECT) or 275-pound burst strength rate as those are the two “magical” numbers you can use to exclude Schedule J. If you are proactive and understand what Schedule J is truly meant for, you can use a box to meet the requirements to exclude the dart impacts. While this may cost a bit more money upfront, it’s going to save heartache and headache down the road. Particularly for sterile packages, you want to avoid putting any undue necessary stresses on the packaging system as much as possible.

Bubble Leak Testing

Q:    When performing package integrity testing, the Bubble Leak Procedure is commonly used. What are perceived failures in Tyvek during this test?

A:   The spreading of woven Tyvek fibers may result in what is perceived as a failure during a bubble leak test. When Tyvek is folded, bent, or creased, it often creates a path where the fibers open letting air out giving the perception of a failure. Usually when this happens, dye penetration testing needs to be utilized as a secondary means to evaluate the perceived failure. This article discusses the common perception of failures in Tyvek:

https://www.dupont.com/content/dam/dupont/amer/us/en/safety/public/documents/en/Porous_Sterile_Barrier_Integrity_Testing_Failure_Anomalies.pdf

Accelerated Aging

Q:   What common issues are DDL sees with the sterile barrier system when clients are executing shelf-life studies?

A:   Before putting samples of a sterile package system into accelerated aging, it is critical to understand what specific materials are being used and if they can handle the temperatures and humidities being used during aging. The other common issue that leads to failures during aging is under or over sealing on the package.

Another consideration that should be evaluated closely has to do with products that are hydrolytic and use of humidity within the aging process.  Per ASTM F1980, if a product is hydrolytic then the use of 45-55% RH should be targeted.  If you have a product that is hydrolytic and you are using a multi-layer material with a water based tie-layer, then separating out product aging from package validation aging should be considered as the higher elevated RH may cause delaminating issues with this type of sterile barrier.

Real Time Aging

A:   For real time aging, there are benefits or disadvantages to storing samples internally or with a third party lab. The biggest consideration for real time aging is making sure you are documenting things correctly and have full traceability. The typical engineer stays with a company on average five to seven years these days. Thus, if you are doing a real time aging of 5 or 10 years it is likely a different engineer will be involved when the samples are ready.

One advantage then of having an outside lab, such as DDL, manage real time aging is that we will manage everything for you, so you don’t have to worry about your location of samples or documentation going missing if there is a change internally with your personnel.

Years and years of real time aging data is valuable data, so losing that is a huge risk. Fortunately, ISO 11607 allows you to use accelerate aging data to bring your product to market, but without the real time data you’re running into a huge problem should you be audited by the FDA as they will be looking for the real time data.

How working with an outside testing lab can help

As we’ve discussed, there’s a lot of considerations to be made when choosing your sterile barrier package packaging for successful validation. Many of these considerations can seem daunting but DDL is here to help throughout the process, as ultimately, we want to see our clients succeed. There is nothing worse than having to call someone after there is a failure. The benefit of working with DDL is we are just a phone call away to answer questions and make sure our customers are not going to run into problems.

If you have a packaging system prototype, DDL is happy to help take an initial look at this and point out any potential pitfalls that we may see upfront with the product configuration, packaging materials (tray or pouch), shipping configuration, or where the instructions for use (IFU) are going to be placed in the shipping configuration. Everyone is busy, and there are many pieces engineers don’t always take into consideration before moving forward with a full packaging validation; having a second set of eyes look at it helps ensure things are going to run smoothly the first time.

Feasibility studies are a great way to understand your packaging system before moving forward with full validation. We recommend running feasibility studies without even worrying about the sterilization aspect just to see how well that specific package configuration is going to perform.

Protocol review from an outside lab, such as DDL, is beneficial to make sure your testing is in compliance with the standards. A protocol review also helps an outside lab walk through and better understand what a customer is trying to accomplish to reduce any ambiguity, as well as make sure the test flows better and satisfies things from a compliance aspect. In many cases, it is faster and easier for DDL to generate the test protocol for the customer. We also recommend having separate process validation, package validation and product validation protocols, as it is much cleaner and easier to separate out in case something should go wrong with one or the other.

Please contact us if you have any further questions or need help on an upcoming package testing validation.

Common Questions on Medical Device Package Testing Standards

DDL Packaging Engineers Alison Payton and Scott Levy sat down in the most recent installment of DDL’s PackReview video series to discuss some of the common questions and issues their customers have been dealing with regarding their medical device package testing and some of the recent changes with the various testing standards. The topics they covered include recent changes to ASTM F88, ASTM F1980, ASTM D4169, ISO 11607, and some of the most common questions on environmental conditioning.

ASTM F88 guidance on conducting seal strength testing for trays.

Many of the questions DDL has received lately regarding ASTM F88 for seal strength are about the updates with the new standard that was recently published. The biggest change with the updated standard is with tray packages. In previous versions of the ASTM F88 standard, Techniques A, B, and C offered clear testing instructions for flexible-to-flexible or semi-rigid packages (such as pouches), but it lacked guidance on conducting tests for trays made of flexible-to-rigid or semi-rigid materials. The 2023 revision has rectified this gap by providing users with guidance on conducting seal strength testing for trays.

Environmental Conditioning ASTM F2825

DDL is getting many questions on environmental conditioning, and the two primary questions we are commonly asked are: 1) Should I execute environmental conditioning? 2) How should I do it? There is no doubt that you should do it, as we have had customers tell us the FDA wants to know where their conditioning is at after submission. Performing environmental conditioning is going to better help you understand if your packaging system is robust enough to handle various temperature and humidity extremes.

The three most common standards for environmental conditioning are ASTM D4332, ASTM F2825 and ISTA 3A. Thus, the question we often get is which one should we use? As all three are consensus standards. ASTM D4332 is a standalone document, so some customers like that. The ISTA 3A conditioning profile is very similar to ASTM D4332. Thus, either one is good to use, as both are acceptable under ISO 11607 and are consensus standards by the FDA.

One of the environmental conditioning standards that has gotten people in a little bit of hot water is ASTM F2825. It is a fantastic procedure, but it is intended for next-day shipping. While it is understandable people want to get things done as quickly as possible, you must use the test procedure that best exemplifies how you intend shipping your samples. Thus, if you are shipping next day, absolutely go ahead and use ASTM F2825.

In most cases, it is best to do environmental conditioning before transportation simulation, as you want to see what happens to the samples during transportation simulation after they have gone through conditioning. While doing so may be a bit harsh, this gives you the highest assurance you are not going to run into potential problems down the line.

DDL has also gotten a few questions about ASTM D4169 and the differences between the 2016 revision and the 2022 revision. The newest revision modified “Schedule E” and the air spectrum vibration to better replicate actual anticipated vibratory characteristics that samples will see in air vibration. You may recall within the 2016 revision; the truck spectrum vibration was updated to provide better characterization for the truck spectrum vibration. Just like the truck spectrum vibration, the air spectrum vibration is now made up of low, medium, and high intensities and this schedule no longer uses a single assurance level.  Ultimately this was done because the past vibratory characteristics were more severe than the actual events taking place. We get this question a lot: “Do I need to repeat my transit simulation to meet the new requirements of the 2022 revision?” It is DDL’s belief that the air spectrum vibration within the 2016 revision is more severe than the 2022 revision. Thus, we recommend that each organization needs to do a gap analysis to determine if they should re-execute testing or generate a rationale that what has been executed in the past can be construed as “worst case”.

ASTM F1980-21

DDL has also been getting many questions about the recently updated ASTM F1980-21 standard and the overall change with using humidity as part of the aging sequence. Traditionally, Accelerated Aging has always been about time and temperature to get your expiration date and humidity was not too much of a consideration as low humidity was primarily utilized. With the new ASTM F1980 standard, the use of specified humidity is required if the polymers that make up the package or product are considered hydrolytic. Understanding the hydrolytic aspect of your materials is probably the single biggest change we have seen with this standard in a long time. ASTM F1980 now does not just incorporate the packaging; it is incorporating the product as well. In the past, there really was not an aging standard for products. The new standard now addresses both packaging and product. This means you need to understand all of the polymers that make up your sterile barrier system and your product polymers. The easiest way to understand this is by checking with the material suppliers and further doing research to ensure you are staying in compliance with the standard. What many customers do not realize is that a justification is needed if you stay with the low humidity aging process. Essentially, for this justification, you will need to have done your research and to further show that the polymers you are utilizing are not considered hydrolytic. Ultimately, what you are concerned about if you have a hydrolytic polymer is the potential for hydrolysis. For example, if you have a hydrolytic polymer and you let it sit on the shelf for a period of time, and that polymer breaks down, what’s the result? Understanding this update is extremely important for MDMs to bring safe and effective devices to market, but it is taking MDMs a long time in many cases to chase this information.

Before starting any validation, it is imperative to understand your full packaging system and how these polymers are going to be affected. For example, if you don’t take the time to write a justification or do the research on the various polymers that make up your product and packaging system, you risk failing your validation if you simply utilize the high humidity aspect of ASTM F1980-21 and the polymers you have are not hydrolytic. Thus, it is important to spend the time and due diligence up-front to research your materials ensuring that a successful validation is executed.  This is not only going to pay off with a successful validation, but will save time and eliminate rework loops, and most of all, get your product to market faster.

ASTM D4169-22 Technical Summary

As you may recall, vibration testing on the truck profiles was updated in ASTM D4169-16.  The ASTM D4169-22 revision makes similar changes, but to the air profiles.

The original air transportation profiles in ASTM D4169 were generally based on data from the Forest Products Lab Report FPL-22 [3] from more than 40 years ago. Limited data that had been collected from actual air transport (PSD shapes and Grms) over the last 10-15 years did not correlate well with the original air vibration profiles referenced in ASTM D4169. Based on that information, it was believed that the original air profiles might need to be amended to better reflect current data.

Based on the studies that the ASTM team evaluated and/or conducted, the vibration levels from wheels up to wheels down of air transportation had a much lower overall Grms level compared to the original air transportation profiles in ASTM D4169.

Below is a comparison of the original ASTM air profiles vs the new air profiles.

In the updated air profile within ASTM D4169-22, the overall Grms levels are lower then what has been previously executed within ASTM D4169-16. Moving forward with the new standard, Schedule E (Truck/Air) spectrum vibration will now be executed without assurance levels – please see below.

If you have any questions about the recently updated ASTM D4169 standard, or need help with an upcoming test, please don’t hesitate to contact us, or call us at 800-229-4235

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