Yes, CORTICOID is a Scrabble word!

Letter values in Scrabble US: C 3, O 1, R 1, T 1, I 1, C 3, O 1, I 1, D 2.

Is it a valid word?

CORTICOID is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a steroid hormone produced by the adrenal cortex or synthesized; administered as drugs they reduce swelling and decrease the body's immune response

Also: adrenal cortical steroid.