A sensitive detection method for measuring the free acid form of latanoprost. It also detects the isopropyl ester form of latanoprost, but with less sensitivity.

• Assay 24 samples in triplicate or 36 samples in duplicate
• Measure latanoprost levels down to 15.5 pg/ml
• Read: Colorimetric at 405 to 420 nm

Latanoprost is 13,14-dihydro-17-phenyl-18,19,20-trinor prostaglandin F₂α isopropyl ester (13,14-dihydro-17-phenyl-18,19,20-trinor PGF₂α isopropyl ester), an F-series prostaglandin analog which has been approved for use as an ocular hypotensive drug.

Prostaglandin esters and other similar derivatives act as prodrugs which are converted to the active free acid form by an esterase/amidase activity in ocular tissues. The free acid form of latanoprost (latanoprost free acid (Lat-FA), or PhXA 85) is 200 times more potent than the isopropyl ester as an FP receptor ligand tested using the recombinant human FP receptor.

Although the exact mechanism of the intraocular hypotensive effect of prostaglandins is unknown, it correlates very closely with the FP receptor ligand binding affinity of FP receptor agonists.

Latanoprost ELISA is a sensitive detection method for measuring the free acid form of Latanoprost. It also detects the isopropyl ester form of Latanoprost, but with less sensitivity. The assay is most appropriate for use when only one of the two forms is present. Samples containing mixtures of both the isopropyl ester and free acid should be purified and the two compounds separated prior to ELISA analysis.