Bioequivalence study of two oral formulations of irbesartan 300 mg in healthy volunteers.

A bioequivalence study of 2 irbesartan (CAS 138402-11-6) film-coated tablet formulations was carried out in 40 healthy volunteers according to an open label, randomized, 2-period, 2-sequence, crossover, single dose and fasting conditions design. The test and reference formulations were administered in 2 treatment days, separated by a washout period of 7 days. Blood samples were drawn up to 96 h following drug administration. Plasma concentrations of irbesartan were obtained by a validated HPLC method using MS/MS detection. Log-transformed AUC0-t and Cmax values were tested for bioequivalence based on the ratios of the geometric LSmeans (test/reference). tmax was analysed nonparametrically. The 90% confidence intervals of the geometric LSmean values for the test/reference ratios for AUC0-t (98.06-109.48%, point estimator 103.61%) and Cmax (88.93-100.87%, point estimator 94.72%) were within the bioequivalence acceptance range of 80-125%. According to the European Guideline on the Investigation of Bioequivalence it may be therefore concluded that test formulation of irbesartan 300 mg film-coated tablet is bioequivalent to the reference formulation. Overall, it was judged that the study was conducted with a good tolerance of the subjects to both study drugs.

Bioequivalence studies for 2 different strengths of irbesartan/hydrochlorothiazide combination in healthy volunteers: 300/25 mg and 300/12.5 mg film-coated tablets.

Two bioequivalence studies of irbesartan (CAS 138402-11-6) and hydrochlorothiazide (CAS 58-93-5) combination at 300/12.5 mg and 300/25 mg strengths were carried out in order to assess the bioequivalence of these film-coated tablet formulations in comparison with the marketed reference formulations.Both studies were performed with 30 healthy volunteers according to an open label, randomized, 2-period, 2-sequence, crossover, single dose and fasting conditions design. In each study, test and reference formulations were administered in 2 treatment days, separated by a washout period of 7 days. Blood samples were drawn up to 72 h following drug administration in case of irbesartan and up to 24 h in case of hydrochlorothiazide. Plasma concentrations of both analytes were obtained by a validated HPLC method using MS/MS detection. Log-transformed AUC0-t and Cmax values were tested for bioequivalence based on the ratios of the geometric LSmeans (test/reference).For both studies, the 90% confidence intervals of the geometric LSmean values for the test/reference ratios for AUC0-t [(irbesartan: 300/12.5 mgstrength: 95.33-111.74%. 300/25 mg strength: 91.27-103.93%) (hydrochlorothiazide: 300/12.5 mg strength: 99.63-107.50%. 300/25 mg strength: 95.72-102.24%)] and Cmax [(irbesartan: 300/12.5 mg strength: 98.73-115.03%. 300/25 mg strength: 97.27-112.12%) (hydrochlorothiazide: 300/12.5 mg strength: 97.34-112.06%. 300/25 mg strength: 93.29-106.38%)] were within the bio-equivalence acceptance range of 80-125%.According to the European Guideline on the Investigation of Bioequivalence it may be therefore concluded that both test formulations are bioequivalent to the corresponding reference formulations. Overall, it was judged that both studies were conducted with a good tolerance of the subjects to study drugs.

Bioequivalence study of 2 orodispersible formulations of zolmitriptan 5 mg in healthy volunteers.

A bioequivalence study of 2 zolmitriptan (CAS 139264-17-8) orodispersible tablet formulations was carried out in 26 healthy volunteers according to an open label, randomized, 2-period, 2-sequence, crossover, single dose and fasting conditions design. The test and reference formulations were administered in 2 treatment days, separated by a washout period of 7 days. Plasma concentrations of zolmitriptan and its active metabolite (N-desmethyl-zolmitriptan) were obtained by LC/MS/MS method. Log-transformed AUCs and Cmax values were tested for bioequivalence based on the ratios of the geometric means (test/reference). Tmax was analysed nonparametrically. The 90% confidence intervals of the geometric mean values for the test/reference ratios for AUC0-t and Cmax were within the bioequivalence acceptance range of 80-125%. According to the European Guideline 1 it may be therefore concluded that test formulation of zolmitriptan 5 mg orodispersible tablet is bioequivalent to the reference formulation.

Bioequivalence study of 2 orodispersible formulations of ondansetron 8 mg in healthy volunteers.

This study was designed to compare the rate and extent of absorption of 2 oral formulations of ondansetron (CAS 99614-02-5) 8 mg orodispersible tablets in healthy volunteers. 22 subjects were administered ondansetron orodispersible tablets of test and reference formulation in a single-dose, 2-period, 2-sequence, fasting, open-label, crossover and randomised study. Plasma concentrations were determined by LC/MS/MS. Log-transformed AUCs and Cmax values were tested for bioequivalence based on the ratios of the geometric means (test/reference). Tmax was analysed nonparametrically. The 90% confidence intervals of the geometric mean values for the test/reference ratios for AUC0-t and Cmax were within the bioequivalence acceptance range of 80-125%. According to the European Guideline [1] it may be therefore concluded that test formulation of ondansetron 8 mg orodispersible tablet is bioequivalent to the reference formulation.

Disección anatómica de la musculatura mímica facial: revisión iconográfica de apoyo a los tratamientos complementarios en rejuvenecimiento facial / Anatomical dissection of the mimic facial musculature: iconographic review as a support to the complementary treatments in facial rejuvenation

A la hora de valorar las múltiples técnicas empleadas en el rejuvenecimiento facial y centrándonos de manera particular en aquellos procedimientos mínimamente invasivos complementarios a las intervenciones habituales en Cirugía Plástica-Estética, cobra especial relevancia el conocimiento exhaustivo de las estructuras musculares implicadas en la mímica facial. A tal efecto, se ha realizado un estudio anatómico en cadáveres frescos, en los que se han disecado las principales estructuras referidas. Se presenta un resumen iconográfico de los músculos faciales implicados, haciendo hincapié en su anatomía descriptiva y funcional, así como un recuerdo de las principales áreas problemáticas por alguna circunstancia especial (presencia de un nervio sensitivo o motor) (AU)

To value the multiple technologies involved in facial rejuvenation and focusing in those minimally invasive complementary procedures to the usual Plastic and Aesthetic Surgeries, it´s very important the exhaustive knowledge of the muscular structures involved in the facial movements. To such an effect, an anatomical study has been realized in fresh corpses, dissecting the principal above-mentioned structures. We present an iconographic summary of the facial implied muscles, emphasizing in his descriptive and functional anatomy, as well as a recollection of the principal problematic areas for some special circumstance (presence of a sensory or motornerve) (AU)

Bioequivalence evaluation of two strengths of risperidone tablet formulations in healthy volunteers.

OBJECTIVE: The objective of the study was to evaluate bioequivalence of two strengths (1 and 2 mg) of oral risperidone tablet formulations (test product manufactured by Vita-Invest, S.A., Barcelona, Spain, reference product manufactured by Janssen-Cilag Ltd., UK). SUBJECTS AND METHODS: In each of the 2 studies, 30 healthy volunteers were administered 1 or 2 mg, respectively, of test or reference formulation under fasting conditions in an open, two-way crossover, controlled, randomized and single-site fashion. Blood withdrawal was performed prior to dosing as well as 15 min, 30 min, 1 h, 1.5 h, 2 h, 3 h, 5 h, 8 h, 12 h, 16 h, 24 h, 48 h, 72 h, and 96 h after drug administration. Plasma concentrations of risperidone and its metabolite 9-hydroxy-risperidone were analyzed using LC/MS/MS. Descriptive data of AUC0-t, AUC0- yen, Cmax, and Cmax/AUC0- yen were log-transformed to evaluate bioequivalence based on the ratios of the geometric means of test and reference formulations. tmax was analyzed using nonparametric methods. RESULTS: The results show that in both studies, 1 and 2 mg formulations, the 90% confidence intervals for the geometric means ratios of the test and reference products for both the parent compound risperidone and its metabolite 9-hydroxy-risperidone were all within the bioequivalence acceptance criteria of 0.80 - 1.25 of the European CPMP and the US FDA guidelines, with the exception of tmax for risperidone parent compound in the 2 mg formulation, which was slightly suprabioequivalent for test formulation. CONCLUSION: This study demonstrated the bioequivalence between the test and the reference product of risperidone of both 1 and 2 mg formulations. Both formulations of each strength may, therefore, be prescribed interchangeably.

Gastric toxicity of racemic ketoprofen and its enantiomers in rat: oxygen radical generation and COX-expression.

OBJECTIVE AND DESIGN: The gastric toxicity of racemic-ketoprofen and its enantiomers (S(+)- and R(-)-ketoprofen), oxygen free radical generation and neutrophil infiltration in response to damage were evaluated in rats. Changes in prostaglandin synthesis, cyclooxygenase expression and glutathione metabolism were also studied. MATERIALS AND METHODS: Studies were performed in Wistar rats. Drugs were given by oral administration: racemic-ketoprofen (100, 50 and 25 mg/kg body weight); S(+) and R(-)-ketoprofen (50, 25 and 12.5 mg/kg body weight). Determinations were made of gastric mucosal injury, lipid peroxidation, xanthine oxidase, myeloperoxidase and superoxide dismutase activities, glutathione levels, glutathione peroxidase and glutathione reductase activities, gastric prostaglandin synthesis (PGE2 levels) and COX-expression. RESULTS: Racemic-ketoprofen dose-dependently exhibited the highest toxicity. In contrast, S(+)-ketoprofen at half the dose of the racemic compound proved to be less ulcerogenic. R(-)-ketoprofen was also less ulcerogenic, but when administered as the racemate exacerbated gastric ulceration caused by S(+)-ketoprofen. Drug administration produced significant increases in lipid peroxidation levels and xanthine-oxidase and a decrease in superoxide dismutase activity. Nevertheless the racemate induced the highest disturbances in oxidative metabolism. No changes in myeloperoxidase values and glutathione metabolism were found. Cyclooxygenase-1 immunoreactivity was observed and did not differ from that in control rats. Cyclooxygenase-2 could also be expressed after treatments. CONCLUSIONS: R(-)-ketoprofen and S(+)-ketoprofen have a comparable gastric toxicity and they both have a better gastric toxicity profile as compared to the racemate. In addition to inhibition of prostaglandin synthesis, damage resulted in an increase of cyclooxygenase-2 protein expression. Oxygen radicals, including superoxide anions, could also be implicated.

Estimation of acute flurbiprofen and ketoprofen toxicity in rat gastric mucosa at therapy-relevant doses.

OBJECTIVE: Since assessment of the acute gastrotoxicity of nonsteroidal antiinflammatory drugs (NSAIDs) in rats requires high doses of the drugs, we sought to establish an experimental model with which this adverse NSAID effect can be estimated at therapy-relevant doses. METHODS: The study was performed with racemic flurbiprofen-trometamol (R/S-FBP), its pure enantiomers S-FBP and R-FBP, and racemic ketoprofen-trometamol (R/S-KP). Two hours after administration of FBP or KP to Sprague-Dawley rats, HCl (0.5 M, 10 ml/kg) was given intragastrically (IG), and the haemorrhagic lesion area in the gastric mucosa quantified 1 h post-HCI. RESULTS: FBP amplified gastric acid injury in a dose-related manner, the rank order of potency being S-FBP > R/S-FBP >> R-FBP. While less than 1 micromol/kg S-FBP and R/S-FBP aggravated acid injury, doses up to 50 micromol/kg failed to cause appreciable damage without subsequent HCl challenge. Similar observations were made with R/S-KP which at doses of > or = 1 micromol/kg aggravated gastric acid injury. There was no significant difference in the gastrotoxicity of FBP when the drug was administered subcutaneously or IG, whereas subcutaneously injected R/S-KP was slightly more toxic than IG R/S-KP. CONCLUSIONS: These data show that FBP- and KP-induced amplification of acid injury in the rat gastric mucosa is a sensitive assay whereby, with single drug dosing, the gastrotoxic potential of these and other NSAIDs may be estimated at therapy-relevant doses that in humans threaten mucosal integrity only following chronic use.

Intestinal toxicity of ketoprofen-trometamol vs its enantiomers in rat. Role of oxidative stress.

OBJECTIVE: Gastrointestinal damage and bleeding are the major side effects of non-steroidal anti-inflammatory drugs (NSAID), however the mechanisms of this ulcerogenic action are not fully understood. It has recently been proposed that neutrophil-and oxygen radical-dependent microvascular injuries may be important prime events that lead to mucosal injury. In addition, other factors like bile flow, intact bacterial flora or feeding conditions may contribute to the formation of lesions. Ketoprofen is a NSAID that exists as a pair of R(-) and S (+) enantiomers; like other 2-arylpropionic acids, its anti-inflammatory effects resides almost exclusively in the S (+) isomer. The present study was undertaken to explore the role of oxidative stress in the pathogenesis of intestinal injury induced by oral administration of racemic ketoprofen and its enantiomers given as their water soluble tromethamine salts. MATERIAL AND METHODS: Evaluation of intestinal damage and activities of oxidative stress related enzymes such as myeloperoxidase (MPO), xanthine-oxidase (XO) and superoxide dismutase (SOD) were studied in an experimental animal model using refed rats. RESULTS: After the oral treatment followed by a refeeding period of 24 h, ketoprofen (100, 50, 25 mg/Kg b.w.) dose-dependently caused longitudinal ulcers on the mesenteric side of the middle and lower intestine lumen. The intestinal toxicity caused by S(+)-ketoprofen was significantly lower than the effect observed after racemate and R(-) enantiomer treatments (P <0.001), though the bioinversion of R(-)-ketoprofen to S(+)-enantiomer that occurs in the rat has to be considered. XO activity was unaffected by the studied drugs. Enhanced enteropathy by the racemate and its R (-)-enantiomer was correlated with a significant increase of MPO activity as an index of neutrophil infiltration, and a decrease in SOD activity (p<0.05 Vs control). S(+)-ketoprofen did not significantly change these parameters. CONCLUSIONS: These results suggest that reactive oxygen metabolites can contribute significantly to the development of intestinal lesions, and that R(-)-ketoprofen present in racemic preparations can enhance the toxic intestinal effects of S (+)-enantiomer via modification of neutrophil migration and oxidative stress.

Synthesis and pharmacological evaluation of new 4-2-(7-heterocyclemethoxynaftalen-2-ylmethoxy)ethylbenzoic acids as LTD(4)-antagonists.

A group of new 4-[2-(7-heterocyclemethoxynaftalen-2-ylmethoxy)ethyl]benzoic acids have been synthesized and pharmacologically evaluated as LTD(4)-antagonists. Thiazole derivatives, especially 4-[2-[7-(4-cyclobutylthiazole-2-ylmethoxyl)naphthalen- 2-ylmetho-xy]et hyl]benzoic acid, present considerable activity and improved pharmacokinetic profiles in comparison with our quinoline containing lead molecule confirming the interest of our compounds as potentially oral antiasthmatics and that the 4-alkylthiazole system can be considered as bioisosteric of the quinoline ring at least in our series of compounds.

Derivation of pharmacophore and CoMFA models for leukotriene D(4) receptor antagonists of the quinolinyl(bridged)aryl series.

The present work focuses on the study of the three-dimensional (3D) structural requirements for the leukotriene D(4) (LTD(4)) antagonistic activity of compounds having the basic quinolinyl(bridged)aryl framework. An approach combining pharmacophore mapping, molecule alignment, and CoMFA models was used to derive a hypothesis for a series of LTD(4) antagonists having the basic diaryl-bridged framework. In this compound series, the produced pharmacophore hypotheses have shown to yield molecule alignments suitable to derive valuable CoMFA models. Model selection focused on (1) obtention of coherent modeling results, (2) consistency with the available SAR data, and (3) ability to predict the activity of an independent set of congeneric molecules. This approach resulted in a combined pharmacophore and CoMFA model that can generally represent the antagonistic activity within a log unit of the measured value for compounds of the series. The resulting pharmacophore (model C) consists of an acidic or negative ionizable function (AC), a hydrogen-bond acceptor (HBA), and three hydrophobic regions (HY) and produces chemically meaningful alignments with the most active compounds of the series mapping the pharmacophore in a extended energetically favorable conformation.

Analysis of antinociceptive effects of flurbiprofen enantiomers in a rat model of arthritic pain.

The potential antinociceptive effects of the S(+)- and R(-)-enantiomers of flurbiprofen (SFB and RFB, respectively) were investigated when given intravenously to rats using the pain-induced functional impairment model in the rat (PIFIR), an animal model of arthritic pain. Groups of 6 rats received either vehicle or the enantiomer in turn and antinociception was determined by evaluating the dose-response curves over time. Although SFB and RFB produced dose-dependent effects with similar efficacy (SFB: 277.4 +/- 29.9 au and RFB: 293.5 +/- 20.1 au), the R(-)-enantiomer was unable to produce any antinociceptive action when assessed at the same dose ranges as SFB. It was necessary to increase the dose of RFB by 100 times to produce similar antinociception. Accordingly, S(+)-flurbiprofen was 100-fold more potent (ED50 = 0.33 +/- 0.13 mg/kg) than its antipode R(-)-(ED50 = 30.0 +/- 1.7 mg/kg). SFB generated from metabolic inversion (> 1%) after i.v. dosage of RFB, as well as impurities of SFB present in RFB preparations, tend to confirm the hypothesis that the efficacy of RFB achieved at 100 mg/kg, similar to that observed with 1 mg/kg of SFB, is attributable to SFB.

Detection of COX-1 and COX-2 isoforms in synovial fluid cells from inflammatory joint diseases.

OBJECTIVE: To investigate the expression of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in cells from synovial fluid (SF) of patients with acute or chronic arthritis. METHODS: SF was obtained from eight patients with acute crystal-induced arthritis, nine with rheumatoid arthritis and four with psoriatic arthritis. COX-1 and COX-2 gene expression was studied by reverse transcriptase-polymerase chain reaction (RT-PCR). Protein expression was detected by Western blotting and immunocytochemistry. RESULTS: There was expression of COX-1 mRNA in all and COX-2 mRNA in most of the SF samples from acute or chronic arthritis. By immunocytochemistry, both COX-1 and COX-2 immunoreactivity was restricted to a variable fraction of mononuclear cells. COX-1 staining was observed in 10-fold more cells than COX-2. By Western blotting, COX-1 protein was detected in 60% of the SF samples and COX-2 in none. There were no differences in the pattern of COX-1 and COX-2 expression between chronic and acute SF samples. CONCLUSION: In arthritis, both COX-1 and COX-2 isoforms are expressed by SF cells. COX-1 is the most abundant isoform. Since the strong COX-1 immunostaining observed in a fraction of mononuclear SF cells is not observed in peripheral blood leucocytes, it may be the result of either the activation or recruitment of a subset of mononuclear cells with a high COX-1 expression level.

Analgesic, antiinflammatory, and antipyretic effects of S(+)-ketoprofen in vivo.

Many studies indicate that the S-enantiomers of arylpropionic (APA) nonsteroidal antiinflammatory drugs (NSAIDs) are the pharmacologically active enantiomers. S(+)-ketoprofen (dexketoprofen) stereoselectively inhibits cyclooxygenase (COX) in vitro but very little is known about the differential activity of ketoprofen enantiomers in vivo. We examined the analgesic, antiinflammatory, and antipyretic activities of S(+)-ketoprofen in rats and mice. First, we measured the antinociceptive action of S(+)-ketoprofen in abdominal pain models. After intravenous administration. 0.5 mg/kg S(+)-ketoprofen inhibited 92.1+/-2.2% of writhing in mice. Stereoselectivity in the activity was detected; intravenous administration of the R(-)-enantiomer resulted in no statistically significant activity in a dose range of 0.15-1 mg/kg. Similar results were obtained after oral administration in mice. In the rat, S(+)-ketoprofen was a more potent analgesic than diclofenac by both intravenous and oral administration. There was no significant difference between the analgesic effect of S(+)-ketoprofen treatment and the twofold dose of the racemic form in both the mouse and rat models. Second, we measured the antiinflammatory activity of S(+)-ketoprofen using a carrageenan-induced paw edema model in the rat. Intravenous administration of 5 mg/kg of S(+)-ketoprofen almost completely inhibited edema formation. After oral administration, S(+)-ketoprofen is both more potent and effective than diclofenac. Third, we measured antipyretic activity. S(+)-ketoprofen showed a marked antipyretic action (ED50 = 1.6 mg/kg) and was the most potent of the NSAIDs tested. S(+)-ketoprofen is a potent antiinflammatory, analgesic, and antipyretic agent in vivo, consistent with its potent anti-COX activity.

Antinociceptive effects of S(+)-ketoprofen and other analgesic drugs in a rat model of pain induced by uric acid.

We investigated the antinociceptive properties of dexketoprofen trometamol [S(+)-ketoprofen tromethamine salt; SKP], a new analgesic, antiinflammatory drug, using the pain-induced functional impairment model in the rat (PIFIR), an animal model of arthritic pain. SKP was compared with racemic ketoprofen tromethamine salt (rac-KP), R(-)-ketoprofen tromethamine salt (RKP), ketorolac (KET), and morphine (MOR). We also assessed the effects of flurbiprofen (rac-FB) and its enantiomers (SFB and RFB) in the same model. Groups of six rats received either vehicle or analgesic drug and antinociception was evaluated by evaluating the dose-response curves over time. SKP was an effective antinociceptive drug in this model and was almost equally potent by either oral or intracerebroventricular administration. The oral potency of SKP was similar to that of oral KET and greater than that of oral MOR. No significant differences were observed between racemic ketoprofen and its enantiomers when administered orally. In the rat, significant bioinversion of RKP to SKP occurs when RKP is given orally. After oral administration of RKP, SKP was detectable in 30 min and surpassed the concentration of RKP after 3 h. Nevertheless, when the compounds were given intracerebroventricularly, some stereoselectivity in favor of SKP was observed. Stereoselectivity was observed with flurbiprofen, an analogue of ketoprofen that does not undergo significant metabolic inversion. Whereas SFB was an effective antinociceptive, RFB had no antinociceptive effect at the doses tested when given either orally or intracerebroventricularly.

Intestinal ulcerogenic effect of S(+)-ketoprofen in the rat.

Nonsteroidal antiinflammatory drugs (NSAIDs) inhibit prostaglandin synthesis in the gastrointestinal mucosa, which can lead not only to stomach ulcers but also ulcers in the small and large intestines. Ulcers of the small intestine are less common than those of the stomach, but intestinal lesions are more life threatening. Although the R(-)-enantiomers of the arylpropionic acid (APA) class of NSAIDs are assumed to lack the toxic effects of cyclooxygenase inhibition, they may contribute to the ulcerogenicity of racemates. We have examined the intestinal ulcerogenic effects of single oral doses of S(+)-ketoprofen compared with racemic ketoprofen in the small intestine and cecum of rats. The toxicity in the small intestine was measured as the weight ratio between portions of intestine showing lesions and the total weight of the tissue. Toxicity in the cecum was evaluated by measuring the size of the ulcers. S(+)-ketoprofen had no significant ulcerogenic effect at 10 or 20 mg/kg. However, racemic ketoprofen was clearly ulcerogenic in the small intestine and cecum at the 40 mg dose. R(-)-ketoprofen at 20 mg/kg does not show any effect in the cecum and only limited ulcerogenesis in the small intestine: The latter effect may be the result of racemic inversion. Therefore, the ulcerogenic action of racemic ketoprofen can be interpreted as a synergism between S(+)- and R(-)-ketoprofen. The mechanism of this synergism is not well understood but may be a general feature of APA NSAIDs.

Stereoselective inhibition of rat brain cyclooxygenase by dexketoprofen.

Although it has been assumed that the effects of nonsteroidal antiinflammatory drugs (NSAIDs) are mainly the result of their action on local synthesis of prostaglandins, there is growing evidence to suggest that they may also exert a central analgesic action. Some authors have suggested that inhibition of prostaglandin synthesis in the brain could contribute to the analgesic action. The effect of dexketoprofen trometamol (tromethamine salt of the enantiomer (+)-S-ketoprofen) on prostaglandin synthesis was investigated in rat brain fragments and in cyclooxygenase preparations from rat brain microsomes. Effects of the (-)-R-enantiomer and the racemic mixture were also evaluated. Significant levels of prostaglandin F2 alpha (PGF2 alpha) were synthesized in rat brain fragments after 10 min of incubation at 37 degrees C. Dexketoprofen was found to be a potent inhibitor of this PGF2 alpha production in rat brain (IC50 = 6.2 nM), and it completely suppressed PGF2 alpha production at 1 microM concentration. In addition, inhibition of PGF2 alpha synthesis by dexketoprofen was highly stereoselective since the enantiomer (-)-R-ketoprofen was significantly less potent (IC50 = 294 nM); with this enantiomer, even at high concentrations such as 1 microM, less than 60% inhibition was achieved. These results correlated with those obtained in the study of racemic ketoprofen and its enantiomers on cyclooxygenase activity of rat brain microsomes, where dexketoprofen also inhibited enzymatic activity stereoselectively. IC50 values obtained for dexketoprofen, (-)-R-ketoprofen, and rac-ketoprofen were 3.5 microM, 45.3 microM, and 5.8 microM, respectively. The above results could be related to the potent analgesic effect of dexketoprofen observed in vivo, which was also stereoselective. Taken together, these findings suggest that prostaglandin synthesis inhibition in rat brain by dexketoprofen could be associated, at least in part, with the analgesic effect of this NSAID.

Differential effect of alkyl chain-modified ether lipids on protein kinase C autophosphorylation and histone phosphorylation.

Analogues of 1-O-octadecyl-2-O-methyl-rac-glycerol-3-phosphocholine (ET-18-OMe), containing a carbonyl group at different positions in the alkyl chain and/or a pentylammonium group in sn-3 of glycerol, were evaluated as inhibitors of protein kinase C (PKC; EC 2.7.1.37). The presence of a carbonyl group in the alkyl chain of Et-18-OMe had a dual role in decreasing the inhibitory effect on histone phosphorylation and activating this reaction at low concentrations of compound. The optimal stimulatory effect was observed with the compound having the carbonyl function in C-7 of the alkyl chain. In contrast, all of these compounds were only inhibitors of PKC autophosphorylation, its potency decreasing progressively with the distance between the carbonyl group and the sn-1 position of glycerol. Replacement of the phosphocholine group of ET-18-OMe by a pentamethylene trimethylammonium group maintained the inhibitory effect on histone phosphorylation and autophosphorylation of PKC, and the simultaneous introduction of a ketone group in C-7 of the alkyl chain did not decrease any of these effects. The effects of all these analogues on PKC autophosphorylation, but not on histone phosphorylation, correlated quite well with their known antiproliferative activity on human tumor cell lines and membranolytic activity.

Stereoselective inhibition of inducible cyclooxygenase by chiral nonsteroidal antiinflammatory drugs.

The stereoselective inhibition of inducible cyclooxygenase (COX-2) by chiral nonsteroidal antiinflammatory drugs (NSAIDs)--ketoprofen, flurbiprofen, and ketorolac--has been investigated. The activity and inhibition of COX-2 was assessed in three different in vitro systems: guinea pig whole blood, lipopolysaccharide (LPS)-stimulated human monocytes, and purified preparations of COX-2 from sheep placenta. The results were compared with the inhibition of constitutive cyclooxygenase (COX-1) in three parallel in vitro models: clotting guinea pig blood, human polymorphonuclear leukocytes, and purified COX-1 from ram seminal vesicles. In the whole blood model, both isoenzymes were inhibited by S-enantiomers with equal potency but S-ketoprofen was the most active on COX-2 (IC50 = 0.024 mumol/L). In contrast, both isoenzymes were inhibited less than 40% by all three R-enantiomers at high concentration (> 1 mumol/L). The inhibition of COX by the R-enantiomers may be attributed to contamination with the S-enantiomers (approximately 0.5%). A significant degree of enantioselectivity in COX-2 inhibition was also observed in intact cells. The S-enantiomers inhibited COX-2 from monocytes with IC50 values in the range of 2 to 25 nmol/L, being 100 to 500-fold more potent than the corresponding R-enantiomers. Finally, S-ketoprofen inhibited COX-2 from sheep placenta (IC50 = 5.3 mumol/L) with slightly less potency than S-ketorolac (IC50 = 0.9 mumol/L) and S-flurbiprofen (IC50 = 0.48 mumol/L), whereas the R-enantiomers were found to be essentially inactive (IC50 > or = 80 mumol/L). It is concluded that the chiral NSAIDs studied here inhibit with comparable stereoselectivity both COX-2 and COX-1 isoenzymes, and that the inhibition of COX-2 previously observed for racemic NSAIDs should be attributed almost exclusively to their S-enantiomers.

Effect of manoalide on human 5-lipoxygenase activity.

The marine natural product manoalide (MLD) has been described to inactivate phospholipase A2 (PLA2) from several sources as well as to inhibit synthesis of eicosanoids in human polymorphonuclear leukocytes (HPMNL). MLD also reduces chemically-induced inflammation in vivo. In this investigation we have examined the effect of MLD on A23187-induced generation of leukotriene B4 (LTB4) and thromboxane B2 (TXB2) in HPMNL as well as 5-lipoxygenase (5-LO) activity from HPMNL sonicated preparations. In the intact cell system, MLD inhibited with similar potency biosynthesis of LTB4 and TXB2 (IC50 1.7 and 1.4 microM, respectively). In order to discern if inhibition of 5-LO is involved in the effect of MLD, we examined the action of this compound on 5-LO activity from 10,000 x g and 100,000 x g supernatants of sonicated HPMNL homogenates. The enzymatic activity was not affected at concentrations of MLD up to 50 microM. These data indicate that MLD is not a direct inhibitor of 5-LO activity from HPMNL and support the hypothesis that its anti-inflammatory action could be related with a reduction of eicosanoid biosynthesis via inhibition of PLA2.