Oxaceprol, a structural analog of hydroxyproline, has been used for several years for the treatment of osteoarthritis and rheumatoid arthritis, showing good gastrointestinal safety, particularly in comparison with NSAIDs. It was shown that oxaceprol does not inhibit the synthesis of prostaglandins in vitro, but acts predominantly by inhibiting leukocyte adhesion and migration, thus inhibiting inflammation at an early stage and helps in pain relief.

Firocoxib is a selective COX-2 inhibitor which was approved by FDA and EMEA for the treatment of osteoarthritis and postoperative pain in dogs (Previcox trade name) and horses (Equioxx trade name). The drug is not for human use.

DIMETHYL SULFONE is a compound that contains sulfur. It is a naturally occurring organosulfur compound utilized as a complementary and alternative medicine (CAM) under a variety of names including dimethyl sulfone, methyl sulfone, sulfonylbismethane, organic sulfur, or crystalline dimethyl sulfoxide. Its most common use is as anti-inflammatory agent. DIMETHYL SULFONE has been claimed to relieve stress, relieve pain, treat parasitic infections, increase energy, boost metabolism, enhance circulation, and improve wound healing, but there is little supporting scientific evidence. Due to its enhanced ability to penetrate membranes and permeate throughout the body, the full mechanistic function of MSM may involve a collection of cell types and is therefore difficult to elucidate. DIMETHYL SULFONE is recognized as safe by the FDA, but efficacy has yet to be proven. In rats, no adverse events were observed after daily doses of 2 g MSM per kg of body weight. Published clinical trials of DIMETHYL SULFONE did not report any serious side effects, but long-term effects are unknown.

Aspartame (l-aspartyl-l-phenylalanine methyl ester) known to the public as NutraSweet has been the subject of controversy since it first became an ingredient in food products. The perceived sweetness of aspartame in humans is due to its binding of the heterodimer G-protein coupled receptor formed by the proteins TAS1R2 and TAS1R3. Aspartame was used in experiments on animals to study its role in delays of osteoarthritis. It was shown, that aspartame improved bone cortical density and muscle mass, and might contribute to a better quality of life for these diseased animals. In addition, was investigated the effect in patients with sickle cell anemia. It was revealed, that oral administration of aspartame lead inhibition of sickle cells. That effect was explained by binding aspartame with two human Bence Jones proteins: Mcg and Sea. Thus was suggested, that aspartame could interfere with sickle hemoglobin fibril formation. Then several studies showed that aspartame had no effect on the polymerization of sickle hemoglobin.

Acemetacin is a non-steroidal anti-inflammatory drug used for the treatment of osteoarthritis, rheumatoid arthritis, lower back pain, and relieving post-operative pain. It is manufactured by Merck KGaA under the tradename Emflex and is available in the UK as a prescription-only drug. Other brand names for acemetacin include Rheutrop (Austria), Acemetadoc, Acephlogont, Azeat, Rantudil (Germany, Hungary, Mexico, Portugal, Turkey), Gamespir (Greece), Oldan, Reudol (Spain), Tilur (Switzerland), Ost-map (Egypt). Acemetacin is a glycolic acid ester of indomethacin. The pharmacological activity resulting from acemetacin administration in man is derived from the presence of both acemetacin and indomethacin. The precise pharmacological mode of action of acemetacin is not known. However, unlike other NSAIDs, acemetacin is only a relatively weak inhibitor of prostaglandin synthetase. Prostaglandins are known to have an antisecretory and cytoprotective effect on the gastric mucosa. Acemetacin shows activity in many of the established in vitro tests of anti-inflammatory activity including inhibition of the release of a number of mediators of inflammation. Acemetacin is well absorbed after oral administration. Its major metabolite is indomethacin, which, after repeated administration is present at levels in excess of those of acemetacin. Acemetacin is bound to plasma protein to a slightly lesser extent than indomethacin and has a relatively short plasma elimination half-life. It is eliminated by both hepatic and renal mechanisms. The pharmacokinetics appear to be linear at recommended therapeutic doses, unaffected by moderate renal or hepatic impairment, and unchanged in the elderly.

Azapropazone is a non-steroidal anti-inflammatory drug. It is indicated for use in the treatment of rheumatoid arthritis, osteo-arthritis and gout. Gastro-intestinal disturbances, allergic skin rashes and photosensitivity, headache, vertigo, oedema and kidney impairment may occur. Gastro-intestinal bleeding and angioedema have been reported. Pre-treatment with this drug failed to modify plasma concentrations of phenobarbitone. Brain levels of imipramine or desmethyl imipramine were unaffected 60 minutes after oral administration of imipramine.

Lumiracoxib is a COX-2 selective inhibitor non-steroidal anti-inflammatory drug. On August 11, 2007, Australia's Therapeutic Goods Administration (TGA, the Australian equivalent of the FDA) cancelled the registration of lumiracoxib in Australia due to concerns that it may cause liver failure. New Zealand and Canada have also followed suit in recalling the drug. It has never been approved for use in the United States. Lumiracoxib has a different structure from the standard COX-2 inhibitors (e.g. celecoxib). It more closely resembles the structure of diclofenac (one chlorine substituted by fluorine, the phenylacetic acid has another methyl group in meta position), making it a member of the arylalkanoic acid family of NSAIDs. It binds to a different site on the COX-2 receptor than the standard COX-2 inhibitors. It displays extremely high COX-2 selectivity. The mechanism of action of lumiracoxib is due to inhibition of prostaglandin synthesis via inhibition of cyclooygenase-2 (COX-2). Lumiracoxib does not inhibit COX-1 at therapeutic concentrations. Lumiracoxib is used for the acute and chronic treatment of the signs and symptoms of osteoarthritis of the knee in adults.

Acetyl-11-keto-beta-boswellic acid (AKBA), a pentacyclic triterpene, is a component of gum resin of Boswellia serrata. It inhibits 5-lipoxygenase in a selective, enzyme directed, non-redox, and noncompetitive manner. In addition, AKBA inhibited topoisomerase I. It induces apoptosis and exerts antineoplastic properties. 5-LOXIN, a dietary supplement ingredient (Boswellia serrata extract enriched with 30% 3-O-acetyl-11-keto-beta-boswellic acid) is effective in reducing pain and improving physical functioning in osteoarthritis patients.

(R)-Sulindac is the (R)-enantiomer of nonsteroidal anti-inflammatory drug (NSAID) Sulindac, that is marketed in the U.S. by Merck as Clinoril. Sulindac is a prodrug, derived from sulfinylindene, that is converted in vivo to an active sulfide compound by liver methionine sulfoxide reductases (Msr). The (Msr) family of enzymes includes two major classes, MsrA and MsrB, that specifically reduce the S- and R-epimers of Sulindac. Reduction of (R)-Sulindac to Sulindac Sulfide catalyzed by methionine sulfoxide reductase (Msr)-B. The oxidation of both epimers to sulindac sulfone is catalyzed primarily by the microsomal cytochrome P450 (P450) system. (S)-Sulindac increases the activity of the P450 system better than (R)-sulindac, but both epimers increase primarily the enzymes that oxidize (R)-sulindac. Both epimers can protect normal lung cells against oxidative damage and enhance the killing of lung cancer cells exposed to oxidative stress.

(S)-Sulindac is the (S)-enantiomer of nonsteroidal anti-inflammatory drug (NSAID) Sulindac, that is marketed in the U.S. by Merck as Clinoril. Sulindac is a prodrug, derived from sulfinyl-indene, that is converted in vivo to an active sulfide compound by liver methionine sulfoxide reductases (Msr). The (Msr) family of enzymes includes two major classes, MsrA and MsrB, that specifically reduce the S- and R-epimers of Sulindac. Reduction of (S)-Sulindac to Sulindac Sulfide catalyzed by methionine sulfoxide reductase (Msr)-A. The oxidation of both epimers to sulindac sulfone is catalyzed primarily by the microsomal cytochrome P450 (P450) system. (S)-Sulindac increases the activity of the P450 system better than (R)-sulindac, but both epimers increase primarily the enzymes that oxidize (R)-sulindac. Both epimers can protect normal lung cells against oxidative damage and enhance the killing of lung cancer cells exposed to oxidative stress.