(biochemistry) The sugar alcohol (2R,3s,4S)-pentane-1,2,3,4,5-pentol formed by the reduction of ribose

(transitive) To purify; reduce to a fine, unmixed, or pure state; to free from impurities. / (intransitive) To become pure; to be cleared of impure matter.

(pharmacology) A gonadotropin-releasing hormone agonist.

plural of Orbach