Dear Dr. P,
Thank you for reaching out and thank you for reading our articles! The type of packaging and PCM used in temperature-controlled shipping is dependent on the profile of the products being transported. And because this is also dependent on the temperature requirements for the particular products, I can't give specific advice; it really changes from case to case (i.e. whether your product storage specifications are CRT, +2…+8°C, or < -15 … etc.). Packaging and PCM are selected by the organizations that are part of the distribution chain, e.g. by production, packaging, distribution managers, clinical trial center personnel or quality personnel. After selecting the appropriate packaging and materials, both the transportation package and distribution chain should be validated by using e.g. trial shipments that mimic the actual shipment. Then, the temperature within the package should be monitored throughout the distribution chain with data loggers or other temperature monitoring products.
I'm sorry to tell you that I'm not aware of any published guides or regulations that instruct on the type of packaging and PCM to be used. But the most important item here is to select the type of materials that ensure that the required distribution/storage temperature is maintained throughout the whole chain and the temperature data for this chain exists. In this way, we are able to guarantee that temperature sensitive products have not altered or perished during the distribution chain.
Regarding your question about paraffin-based PCM's that are flammable when liquefied, there are several documents in this area that you can take into account (e.g. certificates of trusted partner/company, warning markings…). This question is out of my knowledge area but I have listed here some Organizations, Associations and their publications where you are able to find more information about using PCM's in air or ground transport:
Also, a quick search on academic documents on Phase Change Materials generated these articles. (Some are for purchase.) Note - I haven't read them so I can't speak to the accuracy or credibility of the articles, but offer them only for your consideration.
I hope this is somewhat helpful! We have four other articles that touch briefly on cold chain guidance and recommendations from USP, ISTA, PDA and FDA/ICH .
Thanks again for contacting us! Please email me if you have other questions!
Regulations Expert, Vaisala Life Science