Yes, HEPARIN is a Scrabble word!

Letter values in Scrabble US: H 4, E 1, P 3, A 1, R 1, I 1, N 1.

Is it a valid word?

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

a polysaccharide produced in basophils (especially in the lung and liver) and that inhibits the activity of thrombin in coagulation of the blood; it (trade names Lipo-Hepin and Liquaemin) is used as an anticoagulant in the treatment of thrombosis and in heart surgery

Also: lipo-hepin.

Not playable in Scrabble US: LIQUAEMIN.