Toxicophylaxin is a rather complex term to spell, but its pronunciation is even more challenging. The word contains a few difficult sounds that require the use of the International Phonetic Alphabet (IPA) for proper representation. First, the "x" is pronounced as a voiceless velar fricative sound /k͡s/. Then, the "ph" is not pronounced as an "f," but as an aspirated "p" sound /pʰ/. Additionally, the "o" is pronounced as a short "u" sound /ʌ/. Overall, the word is spelled as it is pronounced, although its complexity may make it challenging to get it right the first time!
An antitoxic phylaxin, a defensive protein which destroys or neutralizes a toxin or other poisonous bacterial product.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.