Loxoprofen is an anti-inflammatory prodrug (NSAID) and a non-selective COX inhibitor with IC50 values of 6.5 and 13.5 μM for COX-1 and COX-2, respectively, in human whole blood assays [1]. Loxoprofen (LOX) is a non-selective cyclooxygenase inhibitor frequently used to research pain and inflammation in chronic and transitory disorders. Its alcohol metabolite is produced by carbonyl reductase (CR) and comprises of active trans-LOX and inactive cis-LOX. In addition, LOX can also be transformed into inactive hydroxylated metabolites (OH-LOXs) by cytochrome P450 (CYP) [2].

By lowering inflammation, loxoprofen sodium (4 mg/kg/day; PO; 1 or 8 weeks) lowers atherosclerosis in mice [3]. By blocking VEGF, loxoprofen sodium (60 μg/mL; oral; 24 days) prevents tumor growth in mice [4].

Animal/Disease Models: ApoE-/- mice (C57BL/6J-Apoetm1Unc), 8 to 16 weeks old, high-fat diet (0.2% cholesterol, 21% saturated fat) [3]
Doses: 4 mg/kg/day, given in drinking water Medication method: Oral administration at 8 to 16 weeks of age or 15 to 16 weeks of age.
Experimental Results: Inhibition of platelet thromboxane production and platelet aggregation. Reduce the extent of atherosclerosis. Inhibits the production of PGE2, TxB2 and PGI2.

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Animal/Disease Models: 6weeks old male C57BL/6 and BDF1 mice, 100 μL suspension of LLC cells and KLN205 cells (2×106 cells/mL) were subcutaneously (sc) (sc) injected into C57BL/6 and BDF1 mice respectively [4].
Doses: 60 μg/mL
Route of Administration: Orally administered daily for 24 days
Experimental Results: Inhibited tumor growth and angiogenesis in LLC tumor mice, inhibited VEGF expression, and inhibited HUVEC tube formation.

Absorption, Distribution and Excretion
Loxoprofen is rapidly and completely absorbed from the GI tract with a bioavailability of 95%. The absorption phase of the medication occurs in the first 4-6 hours after ingestion. Food ingestion with the medication causes a slight decrease in the rate of loxoprofen absorption.
50% renal excretion. This drug is 20% - 30% excreted in the stool.
Loxoprofen has a volume of distribution of 0.16 L/kg.
Most of the drug as unchanged loxoprofen, 6-0-desmethyl loxoprofen (less than 1%) and glucuronide or other conjugates (66-92%). In patients with renal failure, metabolites may accumulate.

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Metabolism / Metabolites
Loxoprofen is a prodrug that is rapidly converted to its active trans-alcohol metabolite by carbonyl reductase in the liver. This same process also results in a cis-alcohol metabolite, though this isomer carries little pharmacological activity. The parent drug has also been observed to undergo oxidation via CYP3A4/5 to two hydroxylated metabolites (M3 and M4) and glucuronidation by UGT2B7 to two glucuronide metabolites (M5 and M6). The alcohol metabolites of loxoprofen also undergo glucuronide conjugation via UGT2B7 to two glucuronide metabolites (M7 and M8) prior to excretion. When applied in topical formulations, loxoprofen is metabolized to its active trans-alcohol form by carbonyl reductase in the skin.

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Biological Half-Life
The elimination half-life of Loxoprofen is approximately 15 hours. Steady concentration is achieved after 2-3 doses.

Protein Binding
99% albumin-bound. At doses of loxoprofen greater than 500 mg/day, clearance of the drug increases as saturation of plasma protein binding occurs at higher doses.

[1]. Evaluation of loxoprofen and its alcohol metabolites for potency and selectivity of inhibition of cyclooxygenase-2. Bioorg Med Chem Lett. 2004;14(5):1201-1203.

[2]. Assessing Drug Interaction and Pharmacokinetics of Loxoprofen in Mice Treated with CYP3A Modulators. Pharmaceutics. 2019;11(9):479. Published 2019 Sep 16.

[3]. Loxoprofen Sodium, a Non-Selective NSAID, Reduces Atherosclerosis in Mice by Reducing Inflammation. J Clin Biochem Nutr. 2010 Sep;47(2):138-47.

[4]. Loxoprofen sodium suppresses mouse tumor growth by inhibiting vascular endothelial growth factor. Acta Oncol. 2003;42(1):62-70.

Loxoprofen is a monocarboxylic acid that is propionic acid in which one of the hydrogens at position 2 is substituted by a 4-[(2-oxocyclopentyl)methyl]phenyl group. A prodrug that is rapidly converted into its active trans-alcohol metabolite following oral administration. It has a role as a non-steroidal anti-inflammatory drug, a non-narcotic analgesic, an antipyretic, an EC 1.14.99.1 (prostaglandin-endoperoxide synthase) inhibitor and a prodrug. It is a monocarboxylic acid and a member of cyclopentanones. It is functionally related to a propionic acid. It is a conjugate acid of a loxoprofen(1-).
Loxoprofen is a propionic acid derivative non-steroidal anti-inflammatory drug. It is marketed under the trade name Loxonin in Brazil, Mexico and Japan by Sankyo, as Loxomac in India, and as Oxeno in Argentina. A transdermal preparation was approved for use in Japan in January 2006.

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Drug Indication
Loxoprofen is non-steroidal anti-inflammatory medication (NSAID) indicated for pain and inflammation related to musculoskeletal and joint disorders. In addition to its effects on pain, it is an antipyretic and anti-inflammatory medication.

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Mechanism of Action
Loxoprofen itself is a prodrug and carries little-to-no pharmacological activity - it is rapidly metabolized to its trans-alcohol form, which is a potent and non-selective inhibitor of cyclooxygenase. Cyclooxygenase (COX) is present in 2 forms, COX-1 and COX-2, with each serving different functions. COX-1 is present in human cells and is constitutively released, performing cellular housekeeping functions such as mucus production and platelet aggregation. COX-2 is induced in human cells post-injury or due to other stimuli, is triggered to appear in large quantities at the sites of injury/stimuli, and is ultimately responsible for the mediation of inflammation and pain. Loxoprofen's active metabolite inhibits both COX isoforms, resulting in reduced expression of several mediators of pain, inflammation, and fever (e.g. prostaglandins, prostacyclin, thromboxane, etc).

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Pharmacodynamics
Loxoprofen is a non-selective inhibitor of cyclooxygenase enzymes, which are responsible for the formation of various biologically active pain, fever, and inflammatory mediators. These include prostaglandins, prostacyclin, thromboxane, and arachidonic acid.

C15H18O3

246.3016

246.125

68767-14-6

Loxoprofen sodium;80382-23-6;Loxoprofen sodium (dihydrate);226721-96-6;Loxoprofen-d4

3965

White to off-white solid powder

1.2±0.1 g/cm3

417.9±20.0 °C at 760 mmHg

108.5 - 111ºC

220.7±18.3 °C

0.0±1.0 mmHg at 25°C

1.568

1.87

1

3

4

18

316

0

YMBXTVYHTMGZDW-UHFFFAOYSA-N

InChI=1S/C15H18O3/c1-10(15(17)18)12-7-5-11(6-8-12)9-13-3-2-4-14(13)16/h5-8,10,13H,2-4,9H2,1H3,(H,17,18)

2-[4-[(2-oxocyclopentyl)methyl]phenyl]propanoic acid

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 (~406.01 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (10.15 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% 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 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.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (10.15 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 3: ≥ 2.5 mg/mL (10.15 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.)