Latanoprost (free acid)-d4

Latanoprost (free acid)-d4 (Lat-FA-d4) contains four deuterium atoms at the 3, 3, 4, and 4 positions. It is intended for use as an internal standard for the quantification of Lat-FA by GC- or LC-mass spectrometry. Latanoprost is an F-series prostaglandin (PG) analog which has been approved for use as an ocular hypotensive drug.{1107} It is the isopropyl ester of a PGF2a analog containing an aromatic group (17-phenyl) in the w-chain. As an isopropyl ester, latanoprost acts as a prodrug which is converted to Lat-FA by endogenous esterase enzymes. Lat-FA is a potent FP receptor agonist with an EC50 value of 3.6 nM for human FP receptors, which is twice the potency of PGF2a and more than 200 times more potent latanoprost.{8322} The efficacy of PG analog esters for the treatment of glaucoma correlates closely with the FP receptor binding affinity of the free acid.{3802} However, Lat-FA is more irritating and less effective than the prodrug latanoprost when applied directly to the eyes of human glaucoma patients.{5358}