macròlida o macròlid?

La denominació correcta en català és macròlid, tal com trobem en el Diccionari.cat i altres obres de referència. En anglès s’anomena macrolide, on la terminació –ide és la mateixa que trobem en noms com oxide (òxid), peptide (pèptid) i molts altres, tal com s’explica a l’Oxford English Dictionary:

Originally, added to the stem of the name of an element to form names of simple compounds of that element with another element or a radical, as oxide, chloride, nitride, phosphide, sulphide (and thence in more complex formations, as hydroxide, oxychloride, and with numerical prefixes, as dioxide, trisulphide, tetrachloride). Later, added to stems representing compounds or groups to form names of simple derivatives, as acetylide, anilide, cyanide, and spec. in names of glycosides formed from sugars, as furanoside, galactoside. Also used more widely (esp. in organic chemistry) in generic names of various types of compound, as amide, anhydride, imide, peptide, proteid, saccharide.

With binary compounds, following the model of oxide, the suffix –ide is conventionally attached to the (contracted) name of the more electronegative of the two elements: thus a compound of nitrogen and oxygen is called a nitrogen oxide rather than an oxygen nitride, whereas a compound of fluorine and oxygen is called an oxygen fluoride rather than a fluorine oxide. So, following the electronegativity criterion, we have chlorine oxide but sodium chloride, carbon disulphide but tungsten carbide, hydrogen bromide but nickel hydride.

En alguns noms amb aquesta terminació, el gènere del terme català és femení i, per tant, acabat en –ida (com amida), cosa que explica la vacil·lació en el cas de macròlid/macròlida.