Medical name: Celecoxib, Celebrex, Celebra, Onsenal

IUPAC- name: 4-[5-(4-Methylphenyl)-3- (trifluoromethyl) pyrazol- 1-yl]benzenesulfonamide

Formula: C17H14F3N3O2S (molar mass: 381,373 g/mol)

Celecoxib, also known as Celebrex, is a non-steroidal anti-inflammatory drug (NSAID). It is used as long-term treatment of physical illnesses like , chronic polyarthritis and Morbus Bechterew. The drug was developed by the US- American pharmacologist Philip Needleman and fielded by a pharmaceutical company called Pfizer.

History:

As vice president and manager of all chemical actions of the pharmaceutical and biotechnological company Pharmacia, Philip Needleman supervised the study of the experimental research of the 2 (COX-2). The enzyme already was discovered by the Birmingham Young University in 1991. Its function is transmitting signals to the brain. Needleman’s ambition was to find a substance which is capable to inhibit the enzyme. On December, 31 in 1998 the research study lead to the NSAID drug Celecoxib. , a similar drug which is able to inhibit COX-2 as well, has been taken off the market due to the fact that the drug caused strokes and heart attacks. As a consequence, an excessive demand for Celecoxib arose, despite of analogical adverse effects. Primary, the drug was created as a pain reliever for a long-term treatment with improved effects to the gastrointestinal passage compared to other NSAIDs. It is effective likewise and .

Celecoxib supposedly is “better in protecting the from serious complications than other drugs”. The company Pharmacia and the concern Pfizer based their advertisement for Celecoxib on this statement. After years it was revealed that they only made the results of the first six months of a clinical trial public, although the trial went on for years. Even though the warning that the drug can cause heart attacks and strokes has been strengthened, Celecoxib nowadays can be acquired under the trade name “Celebrex” and it is one of Pfizer’s best-selling drugs.

Synthesis:

Structure:

COX-1 and COX-2 are both composed of aminoacids. COX-1 persists out of 576 aminoacids, forming a chain of peptid-bonding, while COX-2 consists out of 587. Due to the fact, that both enzymes work in a similar way, their structure is very similar. Nevertheless, they differ in some points from each other, e.g. their length. Selective COX-2 inhibitors, such as Celecoxib, try to use these differences between the enzymes. The essential difference for the selectivity of Celecoxib seems to be the aminoacid at position 523. In COX-2, this position is occupied by valine, while COX-1 shows isoleucin there.

Isoleucin L-Valin D-Valin

Celecoxib, which acts as a to complex the COX enzyme, contains sulfonamidegroup in its structure. This group is destabilized by the delta-methyl- group of the Isoleucin. As a result, Celecoxib can only form stable complexes with COX-2. Crystal structures of COX-2 complexes with Celecoxib or its derivates are known, and may be found at the RCSB Protein Data Bank, however, there is no complex of COX-1 with a comparable ligand such as Celecoxib. For COX-1 complexes, the medicament „“ has the highest relevance.

Effects:

Major task of the enzyme cyclooxygenase-2 (COX-2) is the oxidation of to H2. is a tissue , which is used to synthesize other -causing and relieving , e.g. I2, E2. According to this, there is a direct relation between the Arachidonic acid and , as long as the metabolism is proceeded by the COX-2 enzyme.

Arachidonic acid Prostaglandin H2

The function of COX-2 inhibiting medicals, such as Celecoxib is to stop the systhesis of the inflammation- and pain-causing Prostaglandin H2, by blocking the COX-2 enzyme. Selective COX-2 inhibitors show less adverse effects than non-selective NSAIDs (inhibition of COX-1 and COX-2), because the inhibition of COX-1 may precedes to a defective gastric juice balance, which causes stomach bleeding. COX1 can be found in the whole human body, whereas COX-2 can only be found in certain areas, such as the kidneys. As a selective COX-2 inhibitor, Celecoxib shows pain- relieving effects.

If Celecoxib is taken simoultaneously with anticoagulants (blood clotting inhibitors), there is a higher risk of bleeding. Furthermore, Celecoxib is lowering the impact of antihypertensive drugs (blood presure lowering drugs) and (water flushing drugs). Therefore these anti-indications should be considered when a patient is treated with Celecoxib.

The most frequent adverse effects of Celecoxib are insomnia, vertigo and infections of the upper respiratory tract. Scarce adverse effects might be anemia, tinnitus, urticaria, ataxia, intestinal perforations, gastric ulcer and alopecia. The named adverse effects of the gastroenterological sector seem to have a relation to the selective inhibition. As mentioned above, Celecoxib is a selective COX-2 inhibitor. Nevertheless, it also inhibits the COX-1 enzyme, but to a minor degree. Therefore, the mentioned adverse effects of COX-1 inhibitors are clearly reduced, though still might occur. Moreover, COX-2 inhibitors show some adverse effects to the cardiovascular system, and increase the risk of a cardiovascular incidence, wherefore certain drugs already have been taken off the market (such as: Rofecoxib). The reason therefor seems to be the production of antagonistic . COX-2 systhesizes (Prostaglandin I2) which is opponent to Thromboxan (TXA2), a hormone synthesized by COX-1. If the inhibitor is selective, only one of the two opponent hormones will be synthesized, therefore the balance between them is defective. A higher risk of heart attacks is a result of this disordered hormone balance.

Celecoxib obtains its maximal effect after 2 – 3 hours. The half-value period is 8 – 12 hours. The active blood-concentration is 3%.

Cancer treatment:

In the USA, Celecoxib is a medical treatment for familial adenomatous polyposis (FAP). Patients diseased with FAP start to form polyps in colon and rectum in juvenile age, and mainly show cancer in these areas in age of 40 – 50. The reason for this is a mutation of the adenomatous polyposis coli gene, a tumor-suppressing gene. Placebocontrolled phase-III-researches proved the polyps-supressing effect of Celecoxib. The reason therefor might be the abilitiy of Celecoxib to form complexes with the protein Cadherin-11 (CDH11), which seems to be a essential for tumor progression and is overexprimed in 15% of breast-cancers, in many glioblastomas , and also contributes to pancreatic cancer . Furthermore, COX-2 seems to be affected in multiple steps of cancer-formation. It has the ability to synthesize cancerogenes out of procancerogenes, such as benzpyrene. As one can se, the COX-2 inhibiting effect of Celecoxib also seems to be reason for its cancer-suppressing impacts. Multiple reasearches (pro- and retrospectives) shows, that the taking of NSAIDs over a time period of 10 years half the risk of bowel cancer. The first hint for cancerresearches with NSAIDs and Celecoxib was a patient with rectal cancer, treated with Indometacin und against his pain. As a result, the cancer completely vanished.

Nevertheless, for a medical like Celecoxib, it is really unlikely that it will be used as a single agent in cancer treatment, because the dose rate that would be necessary to impair CDH11 would be too toxic. A molecule, which is related to Celecoxib, is working the same way, but is less toxic, could be a possible cancer treatment.

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