Taprenepag isopropyl (foremrly PF-04217329 or PF-4217329) is a prodrug of CP-544326 (Taprenepag) which is a potent and selective agonist of EP2 (prostaglandin EP receptor 2) with IC50 of 10 nM and EC50 of 2.8 nM. The compound, when dosed as the isopropyl ester prodrug PF-04217329, significantly increased both its ocular bioavailability and corneal permeability. In a clinical study involving patients with primary open angle glaucoma, PF-04217329 (Taprenepag isopropyl), a prodrug of CP-544326 (active acid metabolite), a potent and selective EP(2) receptor agonist, was successfully evaluated for its ocular hypotensive activity. In preclinical species, topical ocular dosing of PF-04217329 resulted in an elevation of cAMP in aqueous humor/iris-ciliary body, indicating in vivo activation of EP(2) target receptors. The treatment was well tolerated. CP-544326 was exposed to the eyes at doses higher than the EC(50) for the EP(2) receptor when PF-04217329 was applied topically. After administering PF-04217329 once daily, normotensive Dutch-belted rabbits, normotensive dogs, and laser-induced ocular hypertensive cynomolgus monkeys showed reductions in IOP of between 30 and 50% in single-day studies, and between 20 and 40% in multiple-day studies when compared to eyes that were dosed with a vehicle. One topical dose resulted in an IOP reduction that lasted for six to twenty-four hours straight. Finally, preclinical data collected thus far seem to favor PF-04217329's clinical development as a novel glaucoma treatment drug.

Physicochemical Properties

Molecular Formula	C27H28N4O5S
Molecular Weight	520.60
Exact Mass	520.178
Elemental Analysis	C, 62.29; H, 5.42; N, 10.76; O, 15.37; S, 6.16
CAS #	1005549-94-9
Related CAS #	Taprenepag; 752187-80-7
PubChem CID	23729077
Appearance	White to off-white solid powder
LogP	5.069
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	8
Rotatable Bond Count	12
Heavy Atom Count	37
Complexity	812
Defined Atom Stereocenter Count	0
SMILES	S(C1C=NC=CC=1)(N(CC1C=CC=C(C=1)OCC(=O)OC(C)C)CC1C=CC(=CC=1)N1C=CC=N1)(=O)=O
InChi Key	NVPXUFQLKWKBHK-UHFFFAOYSA-N
InChi Code	InChI=1S/C27H28N4O5S/c1-21(2)36-27(32)20-35-25-7-3-6-23(16-25)19-30(37(33,34)26-8-4-13-28-17-26)18-22-9-11-24(12-10-22)31-15-5-14-29-31/h3-17,21H,18-20H2,1-2H3
Chemical Name	propan-2-yl 2-[3-[[(4-pyrazol-1-ylphenyl)methyl-pyridin-3-ylsulfonylamino]methyl]phenoxy]acetate
Synonyms	Taprenepag isopropyl; PF-4217329; PF 4217329; PF4217329; PF-04217329; PF04217329; PF 04217329
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	EP2
ln Vitro	In vitro activity: Tappenepag isopropyl is a very selective EP2 receptor agonist. When the left eye receives a vehicle dosage, its intraocular pressure (IOP) usually stays within normal limits. In the right (Taprenepag isopropyl-dosed) eye, IOP is reduced in all dose groups. On Days 22 and 29, the IOP in the high-dose group is so low that it is not measurable (<4mm Hg). With Taprenepag isopropyl administration, there are no clinical signs or changes in body weight observed at any dose, and animals in the low-dose group (0.75 mg/day) do not exhibit any ocular findings[1].
ln Vivo
Enzyme Assay	CP-544326 is a novel, selective and potent EP2 agonist. CP-544326 is at least 270 times more selective for the human EP2 subtype than the other human EP subtypes, 1, 3, and 4, with an IC50 for human EP2 equal to 10 nM (average of two independent experiments; 9 and 11 nM). cAMP levels increased in a dose- and time-dependent manner, yielding an average EC50 of 1.9 nM (1.5 and 2.4 nM; from two independent experiments), according to the cell-based efficacy data using rat EP2-HEP293 cells. The EC50 of 2.8 nM (2.5 and 3.1 nM; from two independent experiments) for CP-544326-mediated cAMP production in human EP2-HEK293 cells was comparable to that of PGE2 (EC50 = 2.6 nM).
Animal Protocol	In this study, three-year-old male cynomolgus monkeys weighing between 2.6 and 5.0 kg are employed. For 28 days, animals receive two daily doses of Taprenepag isopropyl (0.75, 12, or 36 mg/day) in the right eye, and an equivalent volume of vehicle (containing BAC, EDTA, boric acid, and cremophor) in the left eye. To monitor recovery over a 28-day period, 2 more monkeys are added to the high-dose group. The evaluation of clinical signs, body weight, ophthalmic examination, pupillary diameter, corneal staining, pachymetry, and noncontact specular microscopy are the main factors that determine the toxicity outcomes. On Days 1, 8, 15, 22, and 29 of the dosing phase, IOP is measured once during the predose phase and prior to dosing. Thereafter, it is measured once every week for the duration of the recovery period[1].
References	[1]. Investigation of ocular events associated with taprenepag isopropyl, a topical EP2 agonist in development for treatment of glaucoma. J Ocul Pharmacol Ther. 2014 Jun;30(5):429-39.

Solubility Data

Solubility (In Vitro)

DMSO: ≥ 31 mg/mL Water: <1 mg/mL Ethanol: <1 mg/mL

Solubility (In Vivo)

Solubility in Formulation 1: 5 mg/mL (9.60 mM) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 50.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: 5 mg/mL (9.60 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 50.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 5 mg/mL (9.60 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 50.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	1.9209 mL	9.6043 mL	19.2086 mL
	5 mM	0.3842 mL	1.9209 mL	3.8417 mL
	10 mM	0.1921 mL	0.9604 mL	1.9209 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.