-ic : A suffix signifying, in general, relating to, or characteristic of; as, historic, hygienic, telegraphic, etc.

-ic : A suffix, denoting that the element indicated enters into certain compounds with its highest valence, or with a valence relatively higher than in compounds where the name of the element ends in -ous; as, ferric, sulphuric. It is also used in the general sense of pertaining to; as, hydric, sodic, calcic.

Example:
what is the difference between ic sertraline hcl and regular sertraline?

Taxonomy
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Defination from the web: