Therapeutic effects of eperisone on pulmonary fibrosis via preferential suppression of fibroblast activity.

Although the exact pathogenesis of idiopathic pulmonary fibrosis (IPF) is still unknown, the transdifferentiation of fibroblasts into myofibroblasts and the production of extracellular matrix components such as collagen, triggered by alveolar epithelial cell injury, are important mechanisms of IPF development. In the lungs of IPF patients, apoptosis is less likely to be induced in fibroblasts than in alveolar epithelial cells, and this process is involved in the pathogenesis of IPF. We used a library containing approved drugs to screen for drugs that preferentially reduce cell viability in LL29 cells (lung fibroblasts from an IPF patient) compared with A549 cells (human alveolar epithelial cell line). After screening, we selected eperisone, a central muscle relaxant used in clinical practice. Eperisone showed little toxicity in A549 cells and preferentially reduced the percentage of viable LL29 cells, while pirfenidone and nintedanib did not have this effect. Eperisone also significantly inhibited transforming growth factor-ß1-dependent transdifferentiation of LL29 cells into myofibroblasts. In an in vivo study using ICR mice, eperisone inhibited bleomycin (BLM)-induced pulmonary fibrosis, respiratory dysfunction, and fibroblast activation. In contrast, pirfenidone and nintedanib were less effective than eperisone in inhibiting BLM-induced pulmonary fibrosis under this experimental condition. Finally, we showed that eperisone did not induce adverse effects in the liver and gastrointestinal tract in the BLM-induced pulmonary fibrosis model. Considering these results, we propose that eperisone may be safer and more therapeutically beneficial for IPF patients than current therapies.

A2B adenosine receptor inhibition by the dihydropyridine calcium channel blocker nifedipine involves colonic fluid secretion.

The adenosine A2B receptor is a critical protein in intestinal water secretion. In the present study, we screened compound libraries to identify inhibitors of the A2B receptor and evaluated their effect on adenosine-induced intestinal fluid secretion. The screening identified the dihydropyridine calcium antagonists nifedipine and nisoldipine. Their respective affinities for the A2B receptor (Ki value) were 886 and 1,399 nM. Nifedipine and nisoldipine, but not amlodipine or nitrendipine, inhibited both calcium mobilization and adenosine-induced cAMP accumulation in cell lines. Moreover, adenosine injection into the lumen significantly increased fluid volume in the colonic loop of wild-type mice but not A2B receptor-deficient mice. PSB-1115, a selective A2B receptor antagonist, and nifedipine prevented elevated adenosine-stimulated fluid secretion in mice. Our results may provide useful insights into the structure-activity relationship of dihydropyridines for A2B receptor. As colonic fluid secretion by adenosine seems to rely predominantly on the A2B receptor, nifedipine could be a therapeutic candidate for diarrhoea-related diseases.

Chemical modification-mediated optimisation of bronchodilatory activity of mepenzolate, a muscarinic receptor antagonist with anti-inflammatory activity.

The treatment for patients with chronic obstructive pulmonary disease (COPD) usually involves a combination of anti-inflammatory and bronchodilatory drugs. We recently found that mepenzolate bromide (1) and its derivative, 3-(2-hydroxy-2, 2-diphenylacetoxy)-1-(3-phenoxypropyl)-1-azoniabicyclo[2.2.2]octane bromide (5), have both anti-inflammatory and bronchodilatory activities. We chemically modified 5 with a view to obtain derivatives with both anti-inflammatory and longer-lasting bronchodilatory activities. Among the synthesized compounds, (R)-(-)-12 ((R)-3-(2-hydroxy-2,2-diphenylacetoxy)-1-(3-phenylpropyl)-1-azoniabicyclo[2.2.2]octane bromide) showed the highest affinity in vitro for the human muscarinic M3 receptor (hM3R). Compared to 1 and 5, (R)-(-)-12 exhibited longer-lasting bronchodilatory activity and equivalent anti-inflammatory effect in mice. The long-term intratracheal administration of (R)-(-)-12 suppressed porcine pancreatic elastase-induced pulmonary emphysema in mice, whereas the same procedure with a long-acting muscarinic antagonist used clinically (tiotropium bromide) did not. These results suggest that (R)-(-)-12 might be therapeutically beneficial for use with COPD patients given the improved effects seen against both inflammatory pulmonary emphysema and airflow limitation in this animal model.

Antinociception by fluoro-loxoprofen, a novel non-steroidal anti-inflammatory drug with less ulcerogenic effects, in rat models of inflammatory pain.

The use of non-steroidal anti-inflammatory drugs (NSAIDs) for the treatment of inflammatory pain is limited by gastrointestinal complications. The rapid action of NSAIDs is associated with better pain relief. Previously, we demonstrated that fluoro-loxoprofen, a novel NSAID, has less ulcerogenic potential than other NSAIDs, attributable to its gastroprotective properties. The aim of this study was to investigate and compare the effects of fluoro-loxoprofen on inflammatory pain in rats with those of other NSAIDs. Oral administration of fluoro-loxoprofen, loxoprofen, and celecoxib resulted in equivalent analgesic action against yeast-induced inflammatory pain. The antinociceptive effect of fluoro-loxoprofen was maximized within 1 h after administration, which is less time than that observed for loxoprofen (2 h) and celecoxib (3 h). We confirmed that both fluoro-loxoprofen and loxoprofen suppressed the increases in prostaglandin E2 in inflamed paws. In addition to yeast-induced pain, fluoro-loxoprofen produced a similar effect against adjuvant-induced inflammatory pain, with faster peak analgesic effects than those observed for loxoprofen and celecoxib. Taken together, these results suggest that the analgesic effect of fluoro-loxoprofen is equivalent to that of loxoprofen and celecoxib. Moreover, the analgesic effect of fluoro-loxoprofen against inflammatory pain was more rapid than that of other NSAIDs, and this may be associated with its rapid absorption property.

Identification of Mepenzolate Derivatives With Long-Acting Bronchodilatory Activity.

The standard treatment for chronic obstructive pulmonary disease is a combination of anti-inflammatory drugs and bronchodilators. We recently found that mepenzolate bromide (MP), an antagonist for human muscarinic M3 receptor (hM3R), has both anti-inflammatory and short-acting bronchodilatory activities. To obtain MP derivatives with longer-lasting bronchodilatory activity, we synthesized hybrid compounds based on MP and two other muscarinic antagonists with long-acting bronchodilatory activity glycopyrronium bromide (GC) and aclidinium bromide (AD). Of these three synthesized hybrid compounds (MP-GC, GC-MP, MP-AD) and MP, MP-AD showed the highest affinity for hM3R and had the longest lasting bronchodilatory activity, which was equivalent to that of GC and AD. Both MP-GC and MP-AD exhibited an anti-inflammatory effect equivalent to that of MP, whereas, in line with GC and AD, GC-MP did not show this effect. We also confirmed that administration of MP-AD suppressed elastase-induced pulmonary emphysema in a mouse model. These findings provide important information about the structure-activity relationship of MP for both bronchodilatory and anti-inflammatory activities.

Crystal face identification by Raman microscopy for assessment of crystal habit of a drug.

Crystal habit is one of the key crystallographic characteristics of active pharmaceutical ingredients (APIs), especially those that are poorly soluble. X-ray powder diffraction has commonly been used to assess crystal habit; however, it can only provide macro-information regarding crystal habit for a whole powder sample, not for individual crystals. We describe an approach that uses Raman microscopy for the identification of crystal faces to assess crystal habit at the individual particle level. An antiepileptic agent, phenytoin, was used as the model substance. Phenytoin crystals form a primitive orthorhombic cell. Raman microscopy was used to identify three different patterns of Raman spectra, corresponding to the crystallographic axis that was parallel to the polarization direction of the excitation laser. Thus, a combination of Raman spectra, in which the polarization direction was horizontal and vertical to the morphologically long axis of the crystal, characterized the crystal face. Phenytoin crystals were prepared under various conditions, and the horizontal/vertical combinations of Raman spectra were recorded for individual crystals. The dominantly exposed crystal faces for each condition were identified. This analytical method enables micro-view assessments of crystal habit, which are helpful for identifying the habits of APIs alone and in formulations.

Synthesis and biological comparison of enantiomers of mepenzolate bromide, a muscarinic receptor antagonist with bronchodilatory and anti-inflammatory activities.

Chronic obstructive pulmonary disease (COPD) is characterized by abnormal inflammatory responses and airflow limitations. We recently proposed that the muscarinic antagonist mepenzolate bromide (mepenzolate) would be therapeutically effective against COPD due to its muscarinic receptor-dependent bronchodilatory activity as well as anti-inflammatory properties. Mepenzolate has an asymmetric carbon atom, thus providing us with the opportunity to synthesize both of its enantiomers ((R)- and (S)-mepenzolate) and to examine their biochemical and pharmacological activities. (R)- or (S)-mepenzolate was synthesized by condensation of benzilic acid with (R)- or (S)-alcohol, respectively, followed by quaternization of the tertiary amine. As predicted by computational simulation, a filter-binding assay in vitro revealed that (R)-mepenzolate showed a higher affinity for the muscarinic M3 receptor than (S)-mepenzolate. In vivo, the bronchodilatory activity of (R)-mepenzolate was superior to that of (S)-mepenzolate, whereas anti-inflammatory activity was indistinguishable between the two enantiomers. We confirmed that each mepenzolate maintained its original stereochemistry in the lung when administered intratracheally. These results suggest that (R)-mepenzolate may have superior properties to (S)-mepenzolate as a drug to treat COPD patients given that the former has more potent bronchodilatory activity than the latter.

Structure-activity relationship of celecoxib and rofecoxib for the membrane permeabilizing activity.

Non-steroidal anti-inflammatory drugs (NSAIDs) achieve their anti-inflammatory effect by inhibiting cyclooxygenase activity. We previously suggested that in addition to cyclooxygenase-inhibition at the gastric mucosa, NSAID-induced gastric mucosal cell death is required for the formation of NSAID-induced gastric lesions in vivo. We showed that celecoxib exhibited the most potent membrane permeabilizing activity among the NSAIDs tested. In contrast, we have found that the NSAID rofecoxib has very weak membrane permeabilizing activity. To understand the membrane permeabilizing activity of coxibs in terms of their structure-activity relationship, we separated the structures of celecoxib and rofecoxib into three parts, synthesized hybrid compounds by substitution of each of the parts, and examined the membrane permeabilizing activities of these hybrids. The results suggest that the sulfonamidophenyl subgroup of celecoxib or the methanesulfonylphenyl subgroup of rofecoxib is important for their potent or weak membrane permeabilizing activity, respectively. These findings provide important information for design and synthesis of new coxibs with lower membrane permeabilizing activity.

Superiority of pulmonary administration of mepenzolate bromide over other routes as treatment for chronic obstructive pulmonary disease.

We recently proposed that mepenzolate bromide (mepenzolate) would be therapeutically effective against chronic obstructive pulmonary disease (COPD) due to its both anti-inflammatory and bronchodilatory activities. In this study, we examined the benefits and adverse effects associated with different routes of mepenzolate administration in mice. Oral administration of mepenzolate caused not only bronchodilation but also decreased the severity of elastase-induced pulmonary emphysema; however, compared with the intratracheal route of administration, about 5000 times higher dose was required to achieve this effect. Intravenously or intrarectally administered mepenzolate also showed these pharmacological effects. The intratracheal route of mepenzolate administration, but not other routes, resulted in protective effects against elastase-induced pulmonary damage and bronchodilation at a much lower dose than that which affected defecation and heart rate. These results suggest that the pulmonary route of mepenzolate administration may be superior to other routes (oral, intravenous or intrarectal) to treat COPD patients.

Mepenzolate bromide displays beneficial effects in a mouse model of chronic obstructive pulmonary disease.

The clinical treatment of chronic obstructive pulmonary disease (COPD) requires not only an improvement of airflow by bronchodilation but also the suppression of emphysema by controlling inflammation. Here we screen a compound library consisting of clinically used drugs for their ability to prevent elastase-induced airspace enlargement in mice. We show that intratracheal administration or inhalation of mepenzolate bromide, a muscarinic antagonist used to treat gastrointestinal disorders, decreases the severity of elastase-induced airspace enlargement and respiratory dysfunction. Although mepenzolate bromide shows bronchodilatory activity, most other muscarinic antagonists do not improve elastase-induced pulmonary disorders. Apart from suppressing elastase-induced pulmonary inflammatory responses and the production of superoxide anions, mepenzolate bromide reduces the level of cigarette smoke-induced airspace enlargement and respiratory dysfunction. Based on these results, we propose that mepenzolate bromide may be an effective therapeutic for the treatment of COPD due to its anti-inflammatory and bronchodilatory activities.

Suppression of Alzheimer's disease-related phenotypes by geranylgeranylacetone in mice.

Amyloid-ß peptide (Aß) plays an important role in the pathogenesis of Alzheimer's disease (AD). Aß is generated by the secretase-mediated proteolysis of ß-amyloid precursor protein (APP), and cleared by enzyme-mediated degradation and phagocytosis. Transforming growth factor (TGF)-ß1 stimulates this phagocytosis. We recently reported that the APP23 mouse model for AD showed fewer AD-related phenotypes when these animals were crossed with transgenic mice expressing heat shock protein (HSP) 70. We here examined the effect of geranylgeranylacetone, an inducer of HSP70 expression, on the AD-related phenotypes. Repeated oral administration of geranylgeranylacetone to APP23 mice for 9 months not only improved cognitive function but also decreased levels of Aß, Aß plaque deposition and synaptic loss. The treatment also up-regulated the expression of an Aß-degrading enzyme and TGF-ß1 but did not affect the maturation of APP and secretase activities. These outcomes were similar to those observed in APP23 mice genetically modified to overexpress HSP70. Although the repeated oral administration of geranylgeranylacetone did not increase the level of HSP70 in the brain, a single oral administration of geranylgeranylacetone significantly increased the level of HSP70 when Aß was concomitantly injected directly into the hippocampus. Since geranylgeranylacetone has already been approved for use as an anti-ulcer drug and its safety in humans has been confirmed, we propose that this drug be considered as a candidate drug for the prevention of AD.

Prostaglandin E1 -containing nanoparticles improve walking activity in an experimental rat model of intermittent claudication.

OBJECTIVES: Due to the low stability of lipid emulsions, a lipid emulsion of prostaglandin E1 (Lipo-PGE1 ) necessitates daily intravenous drip infusions. To overcome this issue, we developed nanoparticles containing PGE1 (Nano-PGE1 ). Nano-PGE1 showed a good sustained-release profile of PGE1 from the nanoparticles in vitro, which may permit a longer-lasting therapeutic effect to be achieved. We here examined the pharmacological activity of Nano-PGE1 in a rat experimental model of intermittent claudication induced by femoral artery ligation. METHODS: The walking activity of the rat was tested on a rodent treadmill. Tissue levels of PGE1 were determined by enzyme immunoassay, and skeletal muscle angiogenesis (capillary growth) was monitored by immunohistochemical analysis. KEY FINDINGS: PGE1 could be detected in the lesion site one day after the intravenous administration of Nano-PGE1 but not of Lipo-PGE1 . An increased accumulation of Nano-PGE1 in the lesion site compared with control (unlesioned) site was also observed. The ligation procedure reduced the walking activity, which in turn was improved by a single administration of Nano-PGE1 but not of Lipo-PGE1 . The single administration of Nano-PGE1 also stimulated angiogenesis in the skeletal muscle around the ligated artery. CONCLUSIONS: The findings of this study suggest that Nano-PGE1 improves the walking activity of femoral artery-ligated rats through the accumulation and sustained release of PGE1 .

Comparison of pharmacokinetics between loxoprofen and its derivative with lower ulcerogenic activity, fluoro-loxoprofen.

  We recently reported that, compared to loxoprofen (LOX, an non-steroidal anti-inflammatory drug), the LOX derivative fluoro-loxoprofen (F-LOX) is less ulcerogenic but has similar anti-inflammatory activity. Our previous in vitro studies suggested that both LOX and F-LOX are pro-drugs, the active metabolites of which are their trans-alcohol forms. In this study, we compared the pharmacokinetics of F-LOX and LOX in rats. Overall, the pharmacokinetic characteristics of F-LOX, including the formation of metabolites in vivo and in vitro, were comparable to those of LOX. However, F-LOX disappeared from the plasma more rapidly than LOX, which could potentially explain its lower ulcerogenicity. However, we showed that F-LOX produced fewer gastric lesions than LOX, even when a higher plasma concentration of F-LOX was maintained. Similar to LOX, F-LOX was readily metabolized to its trans- and cis-alcohol forms, with a higher level of the trans-alcohol form being observed after oral or intravenous administration of the drug. The preferential formation of the trans-alcohol form was also observed after incubation of F-LOX with rat liver homogenates in vitro. These results suggest that, similar to LOX, F-LOX acts as a pro-drug and that there is a metabolic system that selectively produces its active metabolite.

Suppression of UV-induced wrinkle formation by induction of HSP70 expression in mice.

UV-induced wrinkle formation owing to the degeneration of the extracellular matrix (ECM) is a major dermatological problem in which abnormal activation of matrix metalloproteinases (MMPs) and elastases have important roles. Heat shock protein 70 (HSP70) has cytoprotective and anti-inflammatory activities. In this study, we examined the effect of HSP70 expression on UV-induced wrinkle formation. Mild heat treatment (exposure to heated water at 42 °C) of the dorsal skin of hairless mice induced the expression of HSP70. The long-term repeated exposure to UV induced epidermal hyperplasia, decreased skin elasticity, degeneration of ECM, and wrinkle formation, which could be suppressed in mice concomitantly subjected to this heat treatment. The UV-induced epidermal hyperplasia, decreased skin elasticity, and degeneration of ECM were less apparent in transgenic mice expressing HSP70 than in wild-type mice. UV-induced fibroblast cell death, infiltration of inflammatory cells, and activation of MMPs and elastase in the skin were also suppressed in the transgenic mice. This study provides evidence for an inhibitory effect of HSP70 on UV-induced wrinkle formation. The results suggest that this effect is mediated by various properties of HSP70, including its cytoprotective and anti-inflammatory activities. We propose that HSP70 inducers used in a clinical context could prove beneficial for the prevention of UV-induced wrinkle formation.

Identification of a unique nsaid, fluoro-loxoprofen with gastroprotective activity.

We previously proposed that direct cytotoxicity of NSAIDs due to their membrane permeabilization activity, together with their ability to decrease gastric prostaglandin E(2), contributes to production of gastric lesions. Compared to loxoprofen (LOX), fluoro-loxoprofen (F-LOX) has much lower membrane permeabilization and gastric ulcerogenic activities but similar anti-inflammatory activity. In this study, we examined the mechanism for this low ulcerogenic activity in rats. Compared to LOX, the level of gastric mucosal cell death was lower following administration of F-LOX. However, the gastric level of prostaglandin E(2) was similar in response to treatment with the two NSAIDs. Oral pre-administration of F-LOX conferred protection against the formation of gastric lesions produced by subsequent administration of LOX and orally administered F-LOX resulted in a higher gastric pH value and mucus content. In the presence of a stimulant of gastric acid secretion, the difference in the ulcerogenic activity of F-LOX and LOX was less apparent. Furthermore, an increase in the mucus was observed in gastric cells cultured in the presence of F-LOX in a manner dependent of increase in the cellular level of cAMP. These results suggest that low ulcerogenic activity of F-LOX involves its both low direct cytotoxicity and protective effect against the development of gastric lesions. This protective effect seems to be mediated through an increase in a protective factor (mucus) and a decrease in an aggressive factor (acid).

Expression of 150-kDa oxygen-regulated protein (ORP150) stimulates bleomycin-induced pulmonary fibrosis and dysfunction in mice.

Idiopathic pulmonary fibrosis (IPF) involves pulmonary injury associated with inflammatory responses, fibrosis and dysfunction. Myofibroblasts and transforming growth factor (TGF)-ß1 play major roles in the pathogenesis of this disease. Endoplasmic reticulum (ER) stress response is induced in the lungs of IPF patients. One of ER chaperones, the 150-kDa oxygen-regulated protein (ORP150), is essential for the maintenance of cellular viability under stress conditions. In this study, we used heterozygous ORP150-deficient mice (ORP150(+/-) mice) to examine the role of ORP150 in bleomycin-induced pulmonary fibrosis. Treatment of mice with bleomycin induced the expression of ORP150 in the lung. Bleomycin-induced inflammatory responses were slightly exacerbated in ORP150(+/-) mice compared to wild-type mice. On the other hand, bleomycin-induced pulmonary fibrosis, alteration of lung mechanics and respiratory dysfunction was clearly ameliorated in the ORP150(+/-) mice. Bleomycin-induced increases in pulmonary levels of both active TGF-ß1 and myofibroblasts were suppressed in ORP150(+/-) mice. These results suggest that although ORP150 is protective against bleomycin-induced lung injury, this protein could stimulate bleomycin-induced pulmonary fibrosis by increasing pulmonary levels of TGF-ß1 and myofibroblasts.

Synthesis and biological evaluation of derivatives of 2-{2-fluoro-4-[(2-oxocyclopentyl)methyl]phenyl}propanoic acid: nonsteroidal anti-inflammatory drugs with low gastric ulcerogenic activity.

We previously reported that 2-fluoroloxoprofen has lower gastric ulcerogenic activity than loxoprofen, a nonsteroidal anti-inflammatory drug (NSAID) without selectivity for COX-2. We synthesized derivatives of 2-fluoroloxoprofen and studied their properties. Compared to 2-fluoroloxoprofen, one derivative, 11a, exhibited higher anti-inflammatory activity and an equivalent ulcerogenic effect. These results suggest that 11a could be therapeutically beneficial for use as an NSAID.

Synthesis and biological evaluation of loxoprofen derivatives.

Non-steroidal anti-inflammatory drugs (NSAIDs) achieve their anti-inflammatory actions through an inhibitory effect on cyclooxygenase (COX). Two COX subtypes, COX-1 and COX-2, are responsible for the majority of COX activity at the gastrointestinal mucosa and in tissues with inflammation, respectively. We previously suggested that both gastric mucosal cell death due to the membrane permeabilization activity of NSAIDs and COX-inhibition at the gastric mucosa are involved in NSAID-induced gastric lesions. We have also reported that loxoprofen has the lowest membrane permeabilization activity among the NSAIDs we tested. In this study, we synthesized a series of loxoprofen derivatives and examined their membrane permeabilization activities and inhibitory effects on COX-1 and COX-2. Among these derivatives, 2-{4'-hydroxy-5-[(2-oxocyclopentyl)methyl]biphenyl-2-yl}propanoate 31 has a specificity for COX-2 over COX-1. Compared to loxoprofen, oral administration of 31 to rats produced fewer gastric lesions but showed an equivalent anti-inflammatory effect. These results suggest that 31 is likely to be a therapeutically beneficial and safer NSAID.

Acetaminophen-induced differentiation of human breast cancer stem cells and inhibition of tumor xenograft growth in mice.

It is now believed that cancer stem cells (CSCs) that are resistant to chemotherapy due to their undifferentiated nature drive tumor growth, metastasis and relapse, so development of drugs that induce differentiation of CSCs should have a profound impact on cancer eradication. In this study, we screened medicines that are already in clinical use for drugs that induce differentiation of CSCs. We used MDA-MB-231, a human breast cancer cell line that contains cancer stem cell-like cells. We found that acetaminophen, an anti-inflammatory, antipyretic and analgesic drug, induces differentiation of MDA-MB-231 cells. Differentiation was assessed by observing alterations in cell shape and expression of differentiated and undifferentiated cell markers, a decrease in cell invasion activity and an increase in susceptibility to anti-tumor drugs. This increased susceptibility seems to involve suppression of expression of multidrug efflux pumps. We also suggest that this induction of differentiation is mediated by inhibition of a Wnt/ß-catenin canonical signaling pathway. Treatment of MDA-MB-231 cells with acetaminophen in vitro resulted in the loss of their tumorigenic ability in nude mice. Furthermore, administration of acetaminophen inhibited the growth of tumor xenografts of MDA-MB-231 cells in both the presence and absence of simultaneous administration of doxorubicine, a typical anti-tumor drug for breast cancer. Analysis with various acetaminophen derivatives revealed that o-acetamidophenol has a similar differentiation-inducing activity and a similar inhibitory effect on tumor xenograft growth. These results suggest that acetaminophen may be beneficial for breast cancer chemotherapy by inducing the differentiation of CSCs.

Properties and synthesis of 2-{2-fluoro (or bromo)-4-[(2-oxocyclopentyl)methyl]phenyl}propanoic acid: nonsteroidal anti-inflammatory drugs with low membrane permeabilizing and gastric lesion-producing activities.

We previously proposed that membrane permeabilization activity of NSAIDs is involved in NSAID-induced gastric lesions. We here synthesized derivatives of loxoprofen that have lower membrane permeabilization activity than other NSAIDs. Compared to loxoprofen, the derivatives 10a and 10b have lower membrane permeabilization activity and their oral administration produced fewer gastric lesions but showed an equivalent anti-inflammatory effect. These results suggest that 10a and 10b are likely to be therapeutically beneficial as safer NSAIDs.