Cyclooxygenase-1 (COX-1): IC50 = 0.0027 μmol/L in human polymorphonuclear leukocytes (intact cells); IC50 = 0.48 μmol/L in guinea pig whole blood; IC50 = 0.002 μmol/L in purified ram seminal vesicles [1]
Cyclooxygenase-2 (COX-2): IC50 = 0.0025 μmol/L in lipopolysaccharide-stimulated human monocytes; IC50 = 0.47 μmol/L in guinea pig whole blood; IC50 = 0.48 μmol/L in purified sheep placenta [1]

(S)-Flurbiprofen (10–7 M) completely transcribes the dye's basal and induced PGE2 release [2].

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In guinea pig whole blood, Esflurbiprofen inhibited lipopolysaccharide-induced PGE2 production (COX-2) with an IC50 of 0.47 ± 0.14 μmol/L. At 1 μmol/L, it caused 70-80% inhibition of COX-2 activity. The compound also inhibited thromboxane B2 production (COX-1) in clotting guinea pig whole blood with an IC50 of 0.48 ± 0.31 μmol/L. The stereoselectivity ratio (R/S IC50) for COX-2 inhibition in this model was 123. [1]
In lipopolysaccharide-stimulated human monocytes, Esflurbiprofen potently inhibited PGE2 synthesis with an IC50 of 0.0025 ± 0.002 μmol/L. The R-enantiomer was much less active (IC50 = 1.4 ± 0.45 μmol/L), giving an R/S IC50 ratio of 560. Esflurbiprofen inhibited COX-2 in this intact cell model with enantioselectivity comparable to that observed for COX-1 inhibition. [1]
In human polymorphonuclear leukocytes stimulated with calcium ionophore A23187, Esflurbiprofen inhibited thromboxane B2 production (COX-1) with an IC50 of 0.0027 ± 0.0003 μmol/L, while the R-enantiomer had an IC50 of 0.40 ± 0.16 μmol/L (R/S ratio = 148). The S-enantiomer of flurbiprofen inhibited COX-1 activity with equal or higher potency than COX-2 in these intact cell models. [1]
In purified enzyme preparations, Esflurbiprofen inhibited COX-2 from sheep placenta with an IC50 of 0.48 ± 0.03 μmol/L, whereas the R-enantiomer was essentially inactive (IC50 > 100 μmol/L, R/S > 200). For COX-1 from ram seminal vesicles, Esflurbiprofen had an IC50 of 0.002 ± 0.001 μmol/L, and the R-enantiomer had an IC50 of 22 ± 11 μmol/L (R/S = 11000). The enantioselectivity observed for COX-2 inhibition was comparable to that for COX-1, though NSAIDs inhibited isolated COX-1 to a much higher degree than COX-2. [1]

The activity of purified COX-1 (from ram seminal vesicles) and COX-2 (from sheep placenta) was measured by monitoring the conversion of radiolabeled arachidonic acid to prostaglandins. Enzyme units (10 units) were suspended in 0.5 mL of Tris-HCl buffer (50 mmol/L, pH 8.0) containing glutathione (5 mmol/L), epinephrine (5 mmol/L), and hematin (1 μmol/L) as cofactors. The reaction mixture was preincubated with the test compound for 2 minutes at 37°C. Then, radiolabeled arachidonic acid (6.6 μmol/L, 300,000 dpm) was added and the mixture was incubated for an additional 2 minutes at 37°C. The reaction was terminated by adding 2 mL of n-hexane/ethyl acetate (2:1, v/v), followed by centrifugation at 2,000 × g for 10 minutes. This extraction procedure was repeated twice. Then, 1 mL of ethanol was added to the aqueous phase, and the preparation was centrifuged again at 2,000 × g for 10 minutes. Prostaglandins remained in the aqueous phase, while free arachidonic acid partitioned into the organic phase. Radioactivity in both phases was determined by scintillation counting. The inhibitory effect of Esflurbiprofen was assessed at various concentrations, and IC50 values were calculated. [1]

For human polymorphonuclear leukocytes (HPMNL), cells were isolated from leukocyte concentrates obtained from blood collection centers. The concentrate was mixed with an equal volume of 6% dextran in a buffered solution (Hank's balanced salt solution without Ca2+ and Mg2+, containing 2.5 mmol/L HEPES and 5 g/L BSA, pH 7.4) and incubated for 1 hour at 37°C to sediment erythrocytes. The supernatant containing leukocytes was centrifuged at 1,800 × g for 10 minutes at 4°C. Residual erythrocytes were lysed by resuspending the pellet in distilled water, and the cells were washed in the buffered solution. Leukocytes were further purified by centrifugation over Ficoll. The final HPMNL pellet (viability >95%) was resuspended in phosphate-buffered saline (PBS: 135 mmol/L NaCl, 4.1 mmol/L KCl, 1 mmol/L CaCl2, 0.5 mmol/L MgCl2, 9.6 mmol/L NaH2PO4, 9.6 mmol/L Na2HPO4, pH 7.4) at 2 × 10^7 cells/mL. Aliquots (1 × 10^7 cells/mL) were incubated at 37°C for 30 minutes with Esflurbiprofen or vehicle (DMSO). Stimulation was initiated by adding calcium ionophore A23187 (5 μmol/L). After 10 minutes, the incubation was stopped by adding EDTA and centrifugation at 1,800 × g for 5 minutes at 4°C. Thromboxane B2 concentrations in the supernatant were measured by specific enzyme immunoassay. Blanks and vehicle controls were included in each experiment, and all tests were performed in triplicate. [1]
For COX-2 induction in human monocytes, mononuclear cells were separated from buffy coats using Ficoll-Paque centrifugation (400 × g for 40 minutes at room temperature). The mononuclear cell layer was collected, washed three times, and resuspended in complete DMEM (DMEM buffered with 0.05 mol/L HEPES, pH 7.4, supplemented with 0.5% heat-inactivated fetal calf serum and 4 mmol/L L-glutamine). Aliquots (10 mL) were seeded into plastic Petri dishes and incubated at 37°C in a 5% CO2 humidified atmosphere for 60 minutes. Adherent cells (mainly monocytes, >90%) were recovered by gentle scraping, resuspended in complete DMEM at 3 × 10^6 cells/mL (viability >96%). Isolated monocytes were incubated for 24 hours at 37°C in 5% CO2 with or without lipopolysaccharide (10 μg/mL) in the presence of various concentrations of Esflurbiprofen. After incubation, the supernatant was separated by centrifugation (1,000 × g for 10 minutes) and kept at -80°C until assayed for PGE2 by specific enzyme immunoassay. Blanks and vehicle controls were included, and all tests were performed in triplicate. [1]

Metabolism / Metabolites
The known metabolites of (s)-flurbiprofen include 4-hydroxy-S-flurbiprofen.

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[1]. Stereoselective Inhibition of Inducible Cyclooxygenase by Chiral Nonsteroidal Antiinflammatory Drugs. J Clin Pharmacol. 1996 Jun;36(6):505-12.

[2]. Inflammatory Mediators Do Not Stimulate CGRP Release if Prostaglandin Synthesis Is Blocked by S(+)-flurbiprofen in Isolated Rat Skin. Inflamm Res. 2003 Dec;52(12):519-23.

(S)-Flurbiprofen is a flurbiprofen. It is the enantiomer of (R)-Flurbiprofen. Eflurbiprofen is being investigated in the clinical trial NCT03434197 (Safety and efficacy of SFPP in the treatment of knee osteoarthritis).

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Flurbiprofen is a chiral NSAID of the 2-arylpropionic acid class, and its antiinflammatory and analgesic activities reside primarily in the S-enantiomer (Esflurbiprofen). This study investigated the stereoselective inhibition of both COX-1 and COX-2 by Esflurbiprofen in various biological systems, including guinea pig whole blood, human intact cells (polymorphonuclear leukocytes and LPS-stimulated monocytes), and purified enzymes from ram seminal vesicles (COX-1) and sheep placenta (COX-2). The results demonstrate that Esflurbiprofen inhibits both isoenzymes with high stereoselectivity, and that the inhibition of COX-2 observed for racemic flurbiprofen is almost exclusively due to the S-enantiomer. The R-enantiomer showed minimal activity (IC50 ≥ 50 μmol/L in whole blood and ≥ 1.4 μmol/L in cell models), which may be attributed to contamination with approximately 0.5% of the S-enantiomer. Esflurbiprofen was found to be a potent inhibitor of COX-1 in human polymorphonuclear leukocytes (IC50 = 0.0027 μmol/L) and of COX-2 in LPS-stimulated monocytes (IC50 = 0.0025 μmol/L). In purified enzyme assays, Esflurbiprofen was highly active on COX-1 (IC50 = 0.002 μmol/L) but less potent on COX-2 (IC50 = 0.48 μmol/L), consistent with the known selectivity profile of NSAIDs for COX-1 over COX-2 in cell-free systems. The study concludes that chiral NSAIDs like flurbiprofen inhibit both COX isoforms with comparable stereoselectivity, and that the R-enantiomers are essentially inactive as COX inhibitors. [1]

C15H13FO2

244.2654

244.089

51543-39-6

72099

White to off-white solid powder

1.2±0.1 g/cm3

376.2±30.0 °C at 760 mmHg

109-110ºC(lit.)

181.3±24.6 °C

0.0±0.9 mmHg at 25°C

1.568

4.11

1

3

3

18

286

1

C[C@@H](C1=CC(=C(C=C1)C2=CC=CC=C2)F)C(=O)O

SYTBZMRGLBWNTM-JTQLQIEISA-N

InChI=1S/C15H13FO2/c1-10(15(17)18)12-7-8-13(14(16)9-12)11-5-3-2-4-6-11/h2-10H,1H3,(H,17,18)/t10-/m0/s1

(2S)-2-(3-fluoro-4-phenylphenyl)propanoic acid

BTS-24332; TT 063; BTS24332; TT063; SFPP; BTS 24332; TT-063; Trade name: Loqoa

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~409.40 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (10.23 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (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 25.0 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.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (10.23 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 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)