Prostaglandin F2αethyl amide (PGF2α-NEt), a PGF2α analog featuring an N-ethyl amide modification at the C-1 carboxyl group, possesses ocular hypotensive activity similar to PG esters. Introduced as alternative prostaglandin ocular hypotensive prodrugs, PGF2α-NEt and other PG N-ethyl amides, contrary to claims of not converting to free acids in vivo, have been demonstrated by our laboratory studies to undergo conversion by bovine and human corneal tissue into the respective free acids at a rate of approximately 2.5 µg/g corneal tissue/hr. This suggests PGF2α-NEt is expected to elicit typical PGF2α free acid intraocular effects, albeit with slower hydrolysis kinetics characteristic of PG N-amides.