1. An acidic glycosaminoglycan found especially in lung and liver tissue and having the ability to slow the clotting of blood, used as a drug in the treatment of thrombosis. Also called unfractionated heparin.
2. Any of several anticoagulants, such as enoxaparin, that are derived from this compound by depolymerization and have a lower molecular weight and somewhat different pharmacological properties. Also called low-molecular-weight heparin.
[Late Latin hēpar, liver (from Greek; see ykw in the Appendix of Indo-European roots) + -IN.]
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