Latanoprost acid is the biologically active carboxylic acid form of latanoprost, a prostaglandin F2α analog. It is primarily used as a reference standard, analytical reagent, or intermediate in the pharmaceutical synthesis of latanoprost, which is employed in the treatment of glaucoma and ocular hypertension. Latanoprost acid reduces intraocular pressure by enhancing the outflow of aqueous humor from the eye, helping to prevent optic nerve damage and vision loss. Unlike the isopropyl ester prodrug (latanoprost), the free acid form is not directly administered topically but serves key roles in research, quality control, and drug development.