Flunoxaprofen

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Flunoxaprofen
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Clinical data
ATC code
Identifiers
  • (2S)-2-[2-(4-fluorophenyl)-1,3-benzoxazol-5-yl]propanoic acid
CAS Number
PubChem CID
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
Chemical and physical data
Formula C16H12FNO3
Molar mass 285.274 g·mol−1
3D model (JSmol)
  • C[C@@H](c1ccc2c(c1)nc(o2)c3ccc(cc3)F)C(=O)O
  • InChI=1S/C16H12FNO3/c1-9(16(19)20)11-4-7-14-13(8-11)18-15(21-14)10-2-5-12(17)6-3-10/h2-9H,1H3,(H,19,20)/t9-/m0/s1 X mark.svgN
  • Key:ARPYQKTVRGFPIS-VIFPVBQESA-N X mark.svgN
 X mark.svgNYes check.svgY  (what is this?)    (verify)

Flunoxaprofen, also known as Priaxim, is a chiral nonsteroidal anti-inflammatory drug (NSAID). It is closely related to naproxen, which is also an NSAID. Flunoxaprofen has been shown to significantly improve the symptoms of osteoarthritis and rheumatoid arthritis. The clinical use of flunoxaprofen has ceased due to concerns of potential hepatotoxicity.

Contents

Structure

Flunoxaprofen is a two-ring heterocyclic compound derived from benzoxazole. It also contains a fluorine atom and a propanoyl group.

Synthesis and preparation

Synthesis of flunoxaprofen can be seen here [ citation needed ]

Because flunoxaprofen has limited water-solubility, additional steps must be taken in order to prepare syrups, creams, suppositories, etc. In order to make flunoxaprofen water-soluble, yet still active and efficient, it must be mixed with lysine and then suspended in an organic solvent that is soluble in water. A salt will crystallize upon cooling. The salt must then be filtered out and dried. Pharmacological testing of this now water-soluble compound has shown that it has anti-inflammatory properties equal to flunoxaprofen by itself. [1]

Pharmacokinetics

The efficacy and safety of flunoxaprofen has been compared with those of Naproxen in rheumatoid arthritis patients to show that the two drugs have equivalent therapeutical effects. Both drugs significantly relieve spontaneous pain which occurs both during the day and at night. Both drugs also significantly relieve the pain associated with active and passive motion and aid in relieving morning stiffness. The study also showed both drugs to be equally effective at improving grip strength. [2]

Flunoxaprofen is administered as racemate. The absorption and disposition of both enantiomers were studied in 1988. No significant differences between stereoisomers were detected with respect to their absorption and elimination half-lives. [3] However, further studies have shown that the S-enantiomer is the pharmacologically active form of the drug and does not undergo stereoinversion, while R-Flunoxaprofen is pharmacologically activated through biotransformation to the S-enantiomer. [4] This stereospecific chiral inversion is mediated by the FLX-S-Acyl-CoA thioester. [5] Pharmacokinetic studies with stereoselective bioassays have been carried out in different species after racemate dosage (and flunoxaprofen enantiomer derivatives have also been used as chiral fluorescent derivatizing agents to determine the enantiomers of other drug enantiomers in plasma). [6]

It has been shown that the dextrorotatory form is particularly active and has a much higher therapeutic index than some other anti-inflammatories, including indomethacin and diclofenac. [1] It has also been shown that flunoxaprofen inhibits leukotriene rather than prostaglandin synthesis. This is similar to benoxaprofen. Flunoxaprofen and benoxaprofen have been shown to have similar absorption characteristics. However, the distribution and elimination of flunoxaprofen has been shown to be much faster than benoxaprofen. [7]

Adverse effects

A structural analog of flunoxaprofen is benoxaprofen. The two drugs are carboxylic acid analogs that form reactive acyl glucuronides. Benoxaprofen has been shown to be involved in rare hepatotoxicity. Because of this, benoxaprofen has been removed from the market. In response to this the clinical use of flunoxaprofen has also stopped, even though studies have shown that flunoxaprofen is less toxic than benoxaprofen.

The toxicity of these nonsteroidal anti-inflammatory drugs may be related to the covalent modification of proteins in response to the drugs' reactive acyl glucuronides. The reactivity of the acyl glucuronides appears to co-determine the extent of protein binding, [8] as initially proposed by the research group of Benet et al. in 1993.

Related Research Articles

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Ketoprofen is one of the propionic acid class of nonsteroidal anti-inflammatory drugs (NSAID) with analgesic and antipyretic effects. It acts by inhibiting the body's production of prostaglandin.

<span class="mw-page-title-main">Nonsteroidal anti-inflammatory drug</span> Class of therapeutic drug for relieving pain and inflammation

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<span class="mw-page-title-main">Enantiomer</span> Stereoisomers that are nonsuperposable mirror images of each other

In chemistry, an enantiomer – also called optical isomer, antipode, or optical antipode – is one of two stereoisomers that are nonsuperposable onto their own mirror image. Enantiomers are much like one's right and left hands; without mirroring one of them, hands cannot be superposed onto each other. No amount of reorientation in three spatial dimensions will allow the four unique groups on the chiral carbon to line up exactly. The number of stereoisomers a molecule has can be determined by the number of chiral carbons it has.

<span class="mw-page-title-main">Naproxen</span> Nonsteroidal anti-inflammatory drug (NSAID) used to treat pain

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<span class="mw-page-title-main">Dexibuprofen</span> Chemical compound

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An enantiopure drug is a pharmaceutical that is available in one specific enantiomeric form. Most biological molecules are present in only one of many chiral forms, so different enantiomers of a chiral drug molecule bind differently to target receptors. Chirality can be observed when the geometric properties of an object is not superimposable with its mirror image. Two forms of a molecule are formed from a chiral carbon, these two forms are called enantiomers. One enantiomer of a drug may have a desired beneficial effect while the other may cause serious and undesired side effects, or sometimes even beneficial but entirely different effects. The desired enantiomer is known as an eutomer while the undesired enantiomer is known as the distomer. When equal amounts of both enantiomers are found in a mixture, the mixture is known as a racemic mixture. If a mixture for a drug does not have a 1:1 ratio of its enantiomers it is a candidate for an enantiopure drug. Advances in industrial chemical processes have made it economical for pharmaceutical manufacturers to take drugs that were originally marketed as a racemic mixture and market the individual enantiomers, either by specifically manufacturing the desired enantiomer or by resolving a racemic mixture. On a case-by-case basis, the U.S. Food and Drug Administration (FDA) has allowed single enantiomers of certain drugs to be marketed under a different name than the racemic mixture. Also case-by-case, the United States Patent Office has granted patents for single enantiomers of certain drugs. The regulatory review for marketing approval and for patenting is independent, and differs country by country.

<span class="mw-page-title-main">Fakhreddin Jamali</span> Iranian-Canadian pharmacist

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Chemical compounds that come as mirror-image pairs are referred to by chemists as chiral or handed molecules. Each twin is called an enantiomer. Drugs that exhibit handedness are referred to as chiral drugs. Chiral drugs that are equimolar (1:1) mixture of enantiomers are called racemic drugs and these are obviously devoid of optical rotation. The most commonly encountered stereogenic unit, that confers chirality to drug molecules are stereogenic center. Stereogenic center can be due to the presence of tetrahedral tetra coordinate atoms (C,N,P) and pyramidal tricoordinate atoms (N,S). The word chiral describes the three-dimensional architecture of the molecule and does not reveal the stereochemical composition. Hence "chiral drug" does not say whether the drug is racemic, single enantiomer or some other combination of stereoisomers. To resolve this issue Joseph Gal introduced a new term called unichiral. Unichiral indicates that the stereochemical composition of a chiral drug is homogenous consisting of a single enantiomer.

Chiral inversion is the process of conversion of one enantiomer of a chiral molecule to its mirror-image version with no other change in the molecule.

Chiral analysis refers to the quantification of component enantiomers of racemic drug substances or pharmaceutical compounds. Other synonyms commonly used include enantiomer analysis, enantiomeric analysis, and enantioselective analysis. Chiral analysis includes all analytical procedures focused on the characterization of the properties of chiral drugs. Chiral analysis is usually performed with chiral separation methods where the enantiomers are separated on an analytical scale and simultaneously assayed for each enantiomer.

<span class="mw-page-title-main">Profen (drug class)</span>

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References

  1. 1 2 "Preparation process for making water-soluble lysine salts of (+)2-(4-fluorophenyl)-alpha-methyl-5-benzoxazole acetic acid" U.S. patent 5,120,851
  2. Fioravanti A, Giordano N, Megale F, Jovane D, Franci A, Marcolongo R (1989). "[Efficacy and tolerability of flunoxaprofen in the treatment of rheumatoid arthritis. A cross-over clinical study using naproxen]". La Clinica Terapeutica (in Italian). 131 (2): 83–91. PMID   2533024.
  3. Palatini P, Montanari G, Perosa A, Forgione A, Pedrazzini S, Furlanut M (1988). "Stereospecific disposition of flunoxaprofen enantiomers in human beings". International Journal of Clinical Pharmacology Research. 8 (3): 161–7. PMID   3403103.
  4. Pedrazzini S, De Angelis M, Muciaccia WZ, Sacchi C, Forgione A (1988). "Stereochemical pharmacokinetics of the 2-arylpropionic acid non-steroidal antiinflammatory drug flunoxaprofen in rats and in man". Arzneimittel-Forschung. 38 (8): 1170–5. PMID   3196413.
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  6. Martin E, Quinke K, Spahn H, Mutschler E (1989). "(−)-(S)-flunoxaprofen and (−)-(S)-naproxen isocyanate: two new fluorescent chiral derivatizing agents for an enantiospecific determination of primary and secondary amines". Chirality. 1 (3): 223–34. doi:10.1002/chir.530010308. PMID   2642051.
  7. Furlanut M, Montanari G, Perosa A, Velussi C, Forgione A, Palatini P (1985). "Absorption and disposition kinetics of flunoxaprofen and benoxaprofen in healthy volunteers". International Journal of Clinical Pharmacology Research. 5 (3): 165–70. PMID   4018949.
  8. Dong JQ, Liu J, Smith PC (2005). "Role of benoxaprofen and flunoxaprofen acyl glucuronides in covalent binding to rat plasma and liver proteins in vivo". Biochemical Pharmacology . 70 (6): 937–48. doi:10.1016/j.bcp.2005.05.026. PMID   16046212.