Is ISO 18562 Testing Required for Metered Dose Inhalers (MDIs)?
We all know that inhalers are used intermittently to deliver specific drugs to a specific location. Does that make them a medicinal product or a medical device?
The EU regulations are crystal clear on this. Prefilled inhalers are cited as an example of an Integral Combination Device. That is the medicinal product and the medical device form a single integrated product. They are absolutely intended and designed to be used together and exclusively in this combination.
This means that they need to follow both EU pharmaceutical legislation and the MDR. To put it another way, the combination must have both a marketing authorisation and a CE mark.
This makes the inhaler a ‘breathing system component’ and hence subject to ISO 18562.
Its contact time on each usage is of course very short, just a second or two. But, if it used four times a day over 25 years its cumulative contact time would be 20 hours. That is short term use in the eyes of the standard. Go up to 30 years and it would be a long term device.
The biocompatibility requirements for a breathing component cover particles, gases, and leachates. Particulate testing (ISO 18562-2) testing is most relevant when the inhaler is removed from its packaging. The situation will change after it has been in someone’s pocket for a few days. The gas testing (ISO 18562-3 Test for emissions of volatile organic compounds (VOCs)). Is again most relevant on a new device, but the profile may change over its lifetime. Finally, leachate testing (ISO18562-4) applies only if there is an aqueous fluid path from the device to the patient. This is probably not the case for inhalers. Dry powder inhalers clearly no, gas propelled inhalers if they have a fluid connection it is not aqueous. But, ISO 10993 does come into play here. There is transient mucosal membrane contact when the inhaler or expansion chamber touch the patient’s lips. This should not require specific testing as long as the materials used meet the toxicity requirements of a Biological Evaluation Plan (BEP) and chemical characterisation. There is cumulative contact but if the transfer of materials of concern is negligible to zero with each contact it remains negligible over time.
The conclusion is that MDIs require as a minimum both particulate and VOC testing.