Every component that comes into contact with a product, be it a rubber stopper or blister containers, can release trace substances over time. These substances, known as leachables, are often derived from the polymers, additives, adhesives, or coatings used in manufacturing components and packaging materials. Even in small amounts, leachables can compromise product stability, interfere with formulation, or introduce safety concerns. Identifying them early assists with controlling their impact.
1. Di(2-ethylhexyl)phthalate (DEHP)
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DEHP is a plasticizer used in flexible PVC formulations. It’s found in medical products requiring pliable materials, such as IV bags, catheter lines, and blood storage containers. Such items rely on DEHP-containing PVC for flexibility, however the additive can potentially leach into the product.
Why It Leaches
Since DEHP isn’t chemically bonded to the polymer, it can gradually migrate out of PVC over time. This process is accelerated by heat, long storage durations, or contact with lipid-rich or alcohol-based substances, which act as solvents and enhance its mobility.
Risks
Exposure to DEHP has been associated with hormonal imbalances and adverse effects on reproductive health, including reduced fertility and developmental problems.
Mitigation
- Replace with alternatives like TOTM or elastomers.
- Use multi-layer films to reduce direct exposure to leachables.
2. Bisphenol A (BPA)
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Products made from polycarbonate plastics and epoxy resins are key sources of BPA, spanning medical devices and household items. Syringe barrels, inhaler housings, reusable containers, and food or beverage can linings often incorporate these materials, making them common leachable emitters.
Why It Leaches
BPA can become leachable when its chemical bonds degrade under certain conditions. Repeated heating, prolonged UV exposure, or interaction with acidic or basic substances break down the polymer structure or release residual monomers, increasing the risk of migration into the product over time.
Risks
Unfortunately, BPA can interfere with natural hormone signaling by imitating estrogen, a property that has raised concerns over its role in developmental disorders, metabolic dysfunction, and reproductive health issues.
Mitigation
- Shift to BPA-free materials like COP/COC or polypropylene.
- Add internal coatings to limit exposure, like silicone-based layers, that physically isolate BPA-containing surfaces.
3. Tert-Butylhydroquinone (TBHQ)
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TBHQ is blended into polyethylene and rubber formulations to protect materials from breaking down during processing and storage. This antioxidant is typically utilized in packaging films, rubber seals, and closure components.
Why It Leaches
Its small molecular size and limited interactions with the surrounding polymer network is what causes TBHQ to migrate. TBHQ lacks strong chemical bonding to the surrounding polymer. Consequently, its molecules may shift within the material, particularly when exposed to heat or oily substances that enhance its solubility and mobility.
Risks
At elevated concentrations, TBHQ acts as a pro-oxidant. This can undermine the stability of the very formulations it’s meant to protect. Moreover, due to its leachable nature, TBHQ’s presence has also been linked to inflammatory responses and possible metabolic disturbances when ingested or absorbed through product contact.
Mitigation
- Choose polymer-bound antioxidants like Irganox 1010.
- Isolate TBHQ layers with multi-layer packaging.
4. Zinc Stearate
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During production, zinc stearate is added to molds to prevent sticking and ensure shaped parts like gaskets and syringe plungers are released without damage. While effective throughout processing, some of the compound can remain on the surface or within the part itself. This can form a potential pathway for migration.
Why It Leaches
Zinc stearate migrates thanks to its low molecular weight and limited bonding with the surrounding polymer. It isn’t strongly anchored to the matrix. Therefore, the compound can become a mobile leachable, especially when the finished item is exposed to buffered solutions.
Risks
Though not acutely toxic, this leachable can compromise the performance of drug products through destabilizing protein structures or altering solubility.
Mitigation
- Opt for alternatives like stearyl stearamide.
- Use surface coatings to lock in residues.
5. Butylated Hydroxyanisole (BHA)
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BHA is applied as an antioxidant in plastics and adhesives to slow degradation and extend shelf life. It often turns up in rubber closures, container linings, and blister packaging, where it helps preserve material stability. However, its inclusion in these materials means it may appear as a leachable in the product itself should conditions allow for migration.
Why It Leaches
Leaching occurs when BHA, lacking a chemical bond to the polymer, is drawn toward fatty or nonpolar substances that it dissolves into. If materials containing BHA connect with such substances, it can diffuse out of the packaging and act as a leachable in the product.
Risks
The ability of BHA to migrate into formulations introduces potential risks to both safety and product performance. In addition to potential long-term health effects like endocrine disruption or increased oxidative stress, this leaching can interfere with the performance of sensitive chemical products by reacting with active ingredients or skewing analytical test results.
Mitigation
- Apply foil or barrier layers to restrict migration.
- Screen inputs for trace BHA during quality checks.
Protect Your Products Against The Impact Of Leachables
From plasticizers to antioxidants, leachables can quietly affect the quality and reliability of finished goods. Jordi Labs provides precise extractables and leachables testing to help manufacturers detect and manage these risks. Partner with Jordi Labs to reinforce your quality assurance process and develop safer, more dependable products.
