polymyxin vs antibiotic drug

polymyxin and antibiotic drug both are nouns.

Word	Noun	Adjective	Verb	Adverb
polymyxin	Yes	No	No	No
antibiotic drug	Yes	No	No	No

As nouns, antibiotic drug is a hypernym of polymyxin; that is, antibiotic drug is a word with a broader meaning than polymyxin:

polymyxin: any of several toxic antibiotics obtained from a particular soil bacterium
antibiotic drug: a chemical substance derivable from a mold or bacterium that can kill microorganisms and cure bacterial infections

Other hypernyms of polymyxin include antibiotic.

polymyxin (noun)	antibiotic drug (noun)
any of several toxic antibiotics obtained from a particular soil bacterium	a chemical substance derivable from a mold or bacterium that can kill microorganisms and cure bacterial infections