Motrin
Physical aspects of dexibuprofen and racemic ibuprofen.

Leising G, Resel R, Stelzer F, Tasch S, Lanziner A, Hantich G.

Institut fur Festkorperphysik, Technische Universitat Graz, Austria.

This article presents a comparative study of ibuprofen materials in their solid state. Ibuprofen crystallizes into two different structures for the S(+) enantiomer (dexibuprofen) and racemic ibuprofen. The crystal structure of ibuprofen, its optical absorption and photoluminescence, and the thermodynamic results (melting point and heat of fusion) are discussed. From these physicochemical properties, the authors conclude that dexibuprofen, which is the most active species pharmaceutically, and racemic ibuprofen are inherently different solid-state materials.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9013377&dopt=Abstract ibuprofen Motrin



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Nonsteroidal antiinflammatory drug modulation of behavioral responses to intrathecal N-methyl-D-aspartate, but not to substance P and amino-methyl-isoxazole-propionic acid in the rat.

Bjorkman R, Hallman KM, Hedner J, Hedner T, Henning M.

Division of Clinical Pharmacology, University of Gothenburg, Sweden.

Antinociception by nonsteroidal antiinflammatory drugs, notably diclofenac and S(+)-ibuprofen, has traditionally been attributed to peripheral tissue cyclooxygenase inhibition. This study investigates the potential role of the nitric oxide system for the central antinociceptive effects of diclofenac, S(+)-, and R(-)-ibuprofen. Diclofenac and S(+)- but not R(-)-ibuprofen inhibited the behavioral response dose dependently, "biting, scratching, and licking (BSL)," induced by the spinal application of N-methyl-D-aspartate, but not that of amino-methylisoxazole-propionic acid or substance P. Diclofenac and S(+)-ibuprofen induced a parallel shift in the number of BSL responses and in the duration of the response in the behavioral model at their approximate median effective doses (diclofenac 1 mumol and S(+)-ibuprofen 5 mumol). Pretreatment with L-arginine, the natural substrate for the nitric oxide synthetase, antagonized diclofenac, and S(+)-ibuprofen-induced suppression of the biting, scratching, and licking response evoked by intrathecal N-methyl-D-aspartate. D-arginine did not antagonize the diclofenac- and S(+)-ibuprofen-induced antinociception. The study results indicate that analgesia after diclofenac and S(+)-ibuprofen involves a central mechanism which may add to the peripheral antinociceptive effect of these agents. The central action of diclofenac and S(+)-ibuprofen is partly mediated by an interaction with the N-methyl-D-aspartate receptor and nitric oxide-generating mechanisms.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9013380&dopt=Abstract ibuprofen Motrin



Motrin
Ibuprofen enantiomers and lipid metabolism.

Mayer JM.

Institute of Medical Chemistry, School of Pharmacy, University of Lausanne, Switzerland.

Recent findings concerning the mechanism of the chiral inversion of "profens" have given a better understanding of the ways in which profens interact with lipid biochemistry. This study presents investigations and findings concerning the influence of coenzyme-A (CoA) levels on the chiral inversion of ibuprofen. Measurement of intracellular coenzyme-A levels in isolated rat hepatocytes revealed that R-ibuprofen transiently reduced coenzyme-A levels, whereas S-ibuprofen had no effect. Other experiments were performed with rat hepatocyte suspensions, including tests with various concentrations of clofibric acid added to incubates. Results showed that both clofibric acid pretreatment and its presence in the perfusion medium increases the chiral inversion of R-ibuprofen. These results confirm a metabolic interaction between ibuprofen and clofibric acid. Clinical studies are continuing to determine whether this metabolic interaction has toxicologic consequences.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9013381&dopt=Abstract ibuprofen Motrin



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Mechanistic studies on metabolic chiral inversion of 4-(4-methylphenyl)-2-methylthiomethyl-4-oxobutanoic acid (KE-748), an active metabolite of the new anti-rheumatic agent 2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid (KE-298), in rats.

Yoshida H, Kohno Y, Endo H, Yamaguchi J, Fukushima K, Suwa T, Hayashi M.

Department of Drug Metabolism, Taisho Pharmaceutical Co., Ltd., Saitama, Japan.

The chiral inversion properties of 4-(4-methylphenyl)-2-methylthiomethyl-4-oxobutanoic acid (KE-748), an active metabolite of 2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid (KE-298), were compared with those of ibuprofen in rats. After administration of R(-)-[2 alpha-2H]KE-748, S(+)-KE-748 was present in the rat plasma, and the deuterium atoms of the S(+)-enantiomer were almost all replaced by hydrogen atoms. After administration of S(+)-[2 alpha-2H]KE-748, the deuterium content of S(+)-KE-748 in the plasma remained intact. In the in vitro study, using a cell-free system and rat liver homogenates, the chiral inversion of ibuprofen was apparent when both CoA and ATP were present; however, KE-748 was not inverted. In the study on isolated rat hepatocytes, the unidirectional chiral inversion from R(-)-to S(+)-enantiomer was observed for both ibuprofen and KE-748. When R(-)-ibuprofen was incubated with medium and long chain fatty acids (carbon chain length C6 to C16), using isolated hepatocytes, the chiral inversion decreased significantly. On the other hand, when R(-)-KE-748 was incubated with short and medium chain fatty acids (carbon chain length C3 to C8), chiral inversion was inhibited markedly. To induce hepatic microsomal long chain fatty acid CoA ligase, rats were treated with clofibric acid (CF rats). In both in vitro and in vivo experiments on CF rats, chiral inversion from R(-)-to S(+)-ibuprofen was enhanced significantly compared with that in controls, whereas the enhancement was not observed in the case of R(-)-KE-748. There was no influence of benzoic acid, a typical substrate on medium chain fatty acid CoA ligase in the mitochondrial matrix, on chiral inversion of R(-)-ibuprofen, using, isolated hepatocytes. In contrast, the chiral inversion from R(-)-to S(+)-KE-748 was strongly inhibited in the presence of benzoic acid. These results indicate that chiral inversion of R(-)-KE-748 may proceed via formation of the CoA-thioester intermediate with loss of the 2 alpha-methine proton, in a manner similar to that seem with R(-)-ibuprofen. However, the enzymes needed to form CoA-thioester of R(-)-KE-748 differ from those for R(-)-ibuprofen.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9037250&dopt=Abstract ibuprofen Motrin



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Ibuprofen inhibits the metabolism of the endogenous cannabimimetic agent anandamide.

Fowler CJ, Stenstrom A, Tiger G.

Department of Pharmacology, University of Umea, Sweden.

A measure of the metabolism of anandamide, an endogenous cannabimimetic agent, by rat cerebellar membrane preparations was obtained by following the time-dependent reduction in potency of this compound towards inhibition of binding of the high-affinity cannabinoid agonist ligand [3H]WIN 55212-2 to cannabinoid receptors. Thus for example, incubation of the membranes with 100 nM anandamide for 0, 10 and 30 min. prior to addition of [3H]WIN 55212-2 and phenylmethylsulphonyl fluoride (to inhibit the activity of anandamide amidase, thereby blocking further anandamide metabolism during the binding assay) produced 57 +/- 3, 38 +/- 5 and 19 +/- 7% inhibition, respectively, of [3H]WIN 55212-2 binding. This time-dependent effect was blocked by ibuprofen but not by acetyl salicylic acid, sulindac, acetaminophen or to any significant extent by ketoprofen and naproxen. Preliminary experiments using a direct assay of anandamide amidase with [14C]anandamide as ligand gave an IC50 value for ibuprofen of approximately 400 microM. The potency of ibuprofen as an inhibitor of anandamide metabolism was of the same order of magnitude as required for inhibition of cyclooxygenase-2 in cell-free systems and of the peak plasma concentrations of this drug following a 2 x 200 mg dose regimen. It is concluded that following therapeutic doses of ibuprofen, the metabolism of anandamide may be affected.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9060042&dopt=Abstract ibuprofen Motrin



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Effects of ibuprofen on the in vitro invasiveness of a human transitional cell carcinoma.

Cook GP, Hampton JA.

Department of Urology, Medical College of Ohio Toledo 43614, USA.

Non-steroidal anti-inflammatory drugs, such as ibuprofen, have demonstrated significant anti-cancer activity in both animals and humans. We examined the anti-invasive effects of ibuprofen on the human UM-UC urinary bladder carcinoma cell line using a rapid in vitro tumor cell invasion assay. The inhibitory effects of ibuprofen on the invasiveness and motility of the human UM-UC transitional cell carcinoma (TCC) cell line were evaluated using Matrigel coated polycarbonate filters (8 microns pore size) from Transwell cluster plates. In addition, the potential role of prostaglandin E2 in this process was examined. Ibuprofen exposure at non-cytotoxic concentrations resulted in a significant (p < 0.05) dose-dependent reduction of invasion when compared to vehicle exposed controls. Even at the highest concentration, ibuprofen had no effect on the rate of tumor cell division. Similarly, the highest concentration of ibuprofen did not alter tumor cell motility through uncoated 8 microns-pore polycarbonate filters. Addition of both prostaglandin E2 and ibuprofen to the culture medium restored tumor cell invasiveness through Matrigel-coated membranes to levels nearly identical to vehicle exposed controls (DMSO-no ibuprofen). The results indicate that ibuprofen is effective in preventing tumor cell invasion in this in vitro model. Prostaglandin E2 reverses the anti-invasive effects of ibuprofen. The anti-invasive effect of ibuprofen warrants further study alone or in combination with other therapies used in the treatment of early stage transitional cell carcinoma of the urinary bladder.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9066678&dopt=Abstract ibuprofen Motrin



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Regulation of prostanoid vasomotor effects and receptors in choroidal vessels of newborn pigs.

Abran D, Varma DR, Chemtob S.

Centre de Recherche de l'Hopital Sainte-Justine, Department of Pediatrics, Montreal, Quebec, Canada.

This study was conducted to determine if high perinatal prostaglandin (PG) and thromboxane (TxA2) levels modified their choroidal vasomotor effects and receptor levels. Both nonperfused (eyecup preparations) and perfused choroidal vessels from saline- or ibuprofen-treated 1-day-old pigs and tissues from adult pigs were used; all prostanoids produced similar vasomotor effects on both preparations. Choroidal PGF2alpha, TxA2, PGI2, and PGD2 levels were higher in the newborn than in adult pigs; injections of ibuprofen (40 mg/kg every 4 h for 48 h) into newborn pigs significantly decreased choroidal levels of all these prostanoids. PGF2alpha and the TxA2 mimetic U-46619 caused less choroidal vasoconstriction and production of inositol 1,4,5-trisphosphate (IP3) in the newborn than in adult pigs. Ibuprofen treatment increased choroidal PGF2alpha vasoconstrictor effects, IP3 production, and receptors, but did not modify response to U-46619. Carbaprostacyclin (PGI2 analog) caused a greater choroidal vasodilatation and adenosine adenosine 3',5'-cyclic monophosphate (cAMP) production in the newborn than in adult pigs; these effects were not modified by ibuprofen. PGD2 did not increase cAMP but caused greater dilatation and nitrite [oxidation product of nitric oxide (NO)] production in the choroid of newborn than of adult pigs, which were decreased to adult levels by ibuprofen and the NO synthase inhibitor N(omega)-nitro-L-arginine. These data suggest that high perinatal PG levels downregulate PGF2alpha receptors and vascular effects but do not modify choroidal responses to TxA2 and PGI2; NO seems to contribute to the vasodilator effects of PGD2.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9087666&dopt=Abstract ibuprofen Motrin



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The synergistic analgesic interactions between hydrocodone and ibuprofen.

Kolesnikov YA, Wilson RS, Pasternak GW.

Department of Anesthesiology and Critical Care, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.

The practice of combining opioids with nonsteroidal antiinflammatory drugs is widespread in the clinical management of acute and chronic pain. Using the mouse radiant heat tail-flick nociception model, we observed potent analgesia with hydrocodone. In contrast, ibuprofen as a single drug was inactive in this model of moderate to severe pain, perhaps reflecting its limited analgesic potential. Despite the inactivity of ibuprofen alone in this model, the inclusion of ibuprofen with hydrocodone markedly enhanced the analgesic response. Dose-response studies revealed an 50% effective dose for hydrocodone alone in mice of 11 mg/kg, SC. Inclusion of a fixed ibuprofen dose with the various hydrocodone doses shifted the 50% effective dose value almost seven-fold to the left to 1.6 mg/kg, SC, despite the lack of effect of ibuprofen alone in this model. Using a fixed hydrocodone:ibuprofen ratio (1:40) also revealed a marked four-fold shift to 2.6 mg/kg, SC. These findings suggest a synergistic interaction between ibuprofen and hydrocodone in a noninflammatory pain model. IMPLICATIONS: Opioids are frequently used in combination with nonsteroidal antiinflammatory drugs clinically. These studies demonstrate strong interactions between ibuprofen and hydrocodone, implying synergy between the two drugs, which may help explain their utility when given together.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14633549&dopt=Abstract ibuprofen Motrin