ANSWER
Firstly, we need to know about the ingredient content of the particular salt inhaler. Next, we need to know the purpose of using this salt inhaler:
i.e. Does it carry any medicinal purpose that will be interfering with the normal operation of the physiological function or alleviating a pathological condition & symptoms of a disease?
Hence, we would suggest for you to submit for classification with the National Pharmaceutical Regulatory Agency (NPRA) first before looking into the anti-caking agents.
Please feel free to contact us should you need further assistance. We also offer services in terms of aiding and submitting product classification to the National Pharmaceutical Regulatory Agency (NPRA).
Reference
National Pharmaceutical Regulatory Division. (2019). Drug Registration Guidance Document (DRGD).