Pyrrolizine/indolizine-bearing (un)substituted isoindole moiety: design, synthesis, antiproliferative and MDR reversal activities, and in silico studies.

Two new series of pyrrolizine/indolizine derivative-bearing (un)substituted isoindole moiety were designed and synthesized. The anticancer potential of the new compounds was evaluated against hepatocellular carcinoma (HepG-2), colorectal carcinoma, colon cancer (HCT-116), and breast cancer (MCF-7) cell lines. Compounds 6d and 6o were the most potent derivatives with IC50 values ranging from 6.02 to 13.87 µM against HePG-2, HCT-116, and MCF-7 cell lines. Moreover, methyl analog of the fluoro-substituted indolizine derivative 6m revealed significant antiproliferative activity against HePG-2, HCT-116, and MCF-7 cancer cell lines with IC50 values of 11.97, 28.37, and 19.87 µM, respectively. The most active anticancer analogs, 6d, 6m, and 6o, were inspected for their putative mechanism of action by estimating their epidermal growth factor receptor (EGFR) and cyclin-dependent kinase (CDK 2) inhibitory activities. Thus, compound 6o displayed the most inhibitory activity against EGFR and CDK 2 with IC50 values of 62 and 118 nM, respectively. Additionally, the quantitative real-time PCR analysis for the P-glycoprotein effect of compounds 6d, 6m, and 6o was performed, in which compound 6o illustrated significant down-regulation of P-gp against the HepG-2 cell line by 0.2732 fold. Mechanistic studies for the most active compounds involving the reversal doxorubicin (DOX) effect of compounds 6d, 6m, and 6o were performed, which illustrated cytotoxic activity with IC50 22.27, 3.88, and 8.79 µM, respectively. Moreover, the apoptotic activity of the most active derivative 6o on HCT-116 cancer cells showed accumulation in the G1 and S phases of the cell cycle.

Determination of Gemcitabine and Sorafenib in Spiked Human Plasma Using Multivariate Model Update Chemometric Methods.

BACKGROUND: Gemcitabine (GEM), a pyrimidine nucleoside, has been used as a first-line treatment in non-small-cell lung cancer (NSCLC). Sorafenib (SOR), a nonselective multi-kinase inhibitor, is used as a chemotherapeutic agent in different types of cancers including NSCLC in preclinical studies. Co-administration of GEM and SOR was found to be effective and well-tolerated in the treatment of NSCLC. OBJECTIVE: The aim of the present work is to determine the studied drugs in spiked human plasma simultaneously through resolving the overlapping spectra and removing the interference of the plasma matrix. METHOD: Two updated chemometric models were developed using UV absorbance of the drugs, which named principal component regression (PCR) and partial least-squares (PLS) for determination of GEM and SOR in the ranges of 5-25 and 2-22 µg/mL, respectively. RESULTS: Validation of the two updated models has been achieved in accordance with US Food and Drug Administration (FDA) guidelines, and the results were satisfactory. The two methods had the advantages of high predictive ability of the studied drugs with high precision and accuracy. Moreover, there was no significant difference obtained when statistical comparison was done between the developed and reported methods, showing good validity of the suggested methods. CONCLUSIONS: The two updated models have the advantages of being rapid, accurate, sensitive, and cost-effective for the determination of GEM and SOR in quality control laboratories without any need for initial separation procedures. HIGHLIGHTS: Two updated chemometric methods, PCR and PLS, were developed for the estimation of GEM and SOR in spiked human plasma using their UV absorbance data.

Determination of Bendamustine, Gemcitabine and Vinorelbine (BEGEV) regimen in spiked human plasma using multivariate model update chemometric methods.

Combination of bendamustine (BEN), gemcitabine (GEM), and vinorelbine (VIB), (BEGEV) regimen, has been proved to be a tolerable, safe and effective regimen in relapsed/refractory classical hodgkin lymphoma (R/R cHL). Two chemometric models named principal component regression (PCR) and partial least squares (PLS) were established for determination and quantification of BEN, GEM and VIB simultaneously in the ranges of 5-25 µg/mL for each of BEN and VIB, while in the range of 10 -30 µg/mL for GEM in pure and spiked plasma using their UV absorbance. The updated methods have been proven their ability to predict the concentrations of the studied drugs and validated according to FDA guidelines showing good results. There was no significant difference between the developed methods and the reported LC-MS/MS method upon statistical comparison was applied. Furthermore, the updated chemometric methods have advantages of being sensitive, accurate and cost effective for estimation of BEN, GEM and VIB and monitoring their concentration.

Development of certain aminoquinazoline scaffolds as potential multitarget anticancer agents with apoptotic and anti-proliferative effects: Design, synthesis and biological evaluation.

Newly designed 4 - aminoquinazoline derivatives (5a-f, 6a, b, 7, 8, 9, 10a-c, 11a, b, 12a, b and 13a, b) have been synthesized and evaluated for their potential multitarget anticancer activities, apoptotic and anti-proliferative effects. Thereupon, in vitro cytotoxic activities of all the synthesized compounds were screened against NCI 60 human cancer cell lines (nine subpanels) at NCI, USA. Successfully, 2-morpholino-N-(quinazolin-4-yl) acetohydrazide 5e was granted an NSC code, owing to its significant potency and broad spectrum of activity against various cancer cell lines; leukemia K-562, non-small cell lung cancer NCI-H522 cells, colon cancer SW-620, melanoma LOX IMVI, MALME-3M, renal cancer RXF 393, ACHN and breast cancer MDA-MB231/ATCC (GI% = 99.6, 161, 126.03, 90.22, 174.47, 139.7, 191 and 97, respectively). Compound 5e showed the best inhibitory activity (GI50 = 1.3 µM) against melanoma LOX IMVI, when tested at five doses against NCI 60 cell lines. Furthermore, compound 5e showed comparable EGFR and CDK2 inhibitory activity results (IC50 = 0.093 ± 0.006 µM and 0.143 ± 0.008 µM, respectively) to those of lapatinib and ribociclib (IC50 = 0.03 ± 0.002 µM and 0.067 ± 0.004 µM, respectively). Western blotting analysis of compound 5e against melanoma LOX IMVI marked out significant reduced EGFR and CDK2 protein expression percentages, up to 32.97% and 34.09%, respectively, if compared to lapatinib (31.18%) and ribociclib (29.66%). Moreover, compound 5e caused clear cell cycle arrests at S phase of renal UO-31 cells and at G1 phase of both breast cancer MCF7 and ovarian cancer IGROV1, associated with remarkable increase of DNA content of the controls. In accordance, it demonstrated promising anti- proliferative and apoptotic activities, showing a significant increase in total apoptotic percentages of renal cancer UO-31, breast cancer MCF7 and ovarian IGROV1 cancer cell lines, if compared to the control untreated cells (from 1.79% to 46.72%, 2.19% to 39.02% and 1.66 to 42.51%, respectively). Molecular modelling and dynamic simulation study results supported the main objectives of the present work.

Ecofriendly LC-MS/MS and TLC-densitometric methods for simultaneous quantitative assay and monitoring of BEGEV regimen, in vivo pharmacokinetic study application.

To date no analytical method has been developed for the determination of the BEGEV regimen and no study has investigated the kinetic interaction between the drugs, to give us priorities for further clinical study, so two rapid, accurate, sensitive and ecofriendly chromatographic methods were developed for the simultaneous determination of bendamustine (BEN), gemcitabine (GEM) and vinorelbine (VIB) using sildenafil (SIL) as an internal standard (IS) for the purpose of an in vivo pharmacokinetics study in rats. Firstly, the LC-MS/MS method was performed using a mixture of methanol and a 0.1% aqueous solution of formic acid as the mobile phase on a ZORBAX Eclipse Plus C18 (4.6 mm × 150 mm, 5 µm) column as the stationary phase. BEN, GEM and VIB were ionized by positive ions and detected in the multi-reaction monitoring (MRM) mode using precursor → products of m/z 358.20 → 228.25 for BEN, m/z 264.05 → 112.15 for GEM, m/z 779.55 → 122.20 for VIB and m/z 475.00 → 58.35 for SIL. Secondly, TLC-densitometry was applied on TLC silica gel plates using methanol : ethyl acetate (8 : 2, v/v) as the developing system when the separated peaks were scanned at 280 nm. FDA guidelines were followed for validation of the proposed methods, which presented acceptable ranges; then they were applied for an in vivo study in rats with a quantitative determination of each drug after single or combined administration for an investigation of any suspected drug-drug interaction, and all pharmacokinetic parameters were calculated for therapeutic drug monitoring of those drugs. Green analytical chemistry principles were considered during all the procedural steps to ensure the greenness and the safety of the methods, which were evaluated using four assessment tools, eco-scale assessment, the national environmental method index (NEMI), the green analytical procedure index (GAPI) and the analytical greenness metric approach (AGREE), and the results were satisfactory.

Design, synthesis, biological assessment, and in-Silico studies of 1,2,4-triazolo[1,5-a]pyrimidine derivatives as tubulin polymerization inhibitors.

A series of 1,2,4-triazolo[1,5-a]pyrimidine derivatives have been designed and synthesized as combretastatin CA-4 analogs. They were screened for anticancer and tubulin polymerization inhibition activities. The trimethoxyphenyl 1,2,4-triazolo[1,5-a]pyrimidine derivative 4c showed significant antiproliferative activity in which it exhibited IC50 = 0.53 µM against HCT-116 cancer cell line. It was further tested as a tubulin polymerization inhibitor showing an IC50 = 3.84 µM if compared to combretastatin IC50 = 1.10 µM. Further mechanism studies revealed that compound 4c could obviously inhibit the proliferation of HCT-116 cancer cells by inducing apoptosis and arresting the cell cycle at the G2/M phase. Furthermore, docking studies showed that compound 4c illustrated good fitting to the colchicine binding site of tubulin. Thus, it is considered an anticancer lead compound worthy of further development as a tubulin polymerization inhibitor.

Design, synthesis and mechanistic study of novel diarylpyrazole derivatives as anti-inflammatory agents with reduced cardiovascular side effects.

Novel diarylpyrazole (5a-d, 6a-e, 12, 13, 14, 15a-c and 11a-g) derivatives were designed, synthesized and evaluated for their dual COX-2/sEH inhibitory activities via recombinant enzyme assays to explore their anti-inflammatory activities and cardiovascular safety profiles. Comprehensively, the structures of the synthesized compounds were established via spectral and elemental analyses, followed by the assessment of both their in vitro COX inhibitory and in vivo anti-inflammatory activities. The most active compounds as COX inhibitors were further evaluated for their in vitro 5-LOX and sEH inhibitory activities, alongside with their in vivo analgesic and ulcerogenic effects. Compounds 6d and 11f showed excellent inhibitory activities against both COX-2 and sEH (COX-2 IC50 = 0.043 and 0.048 µM; sEH IC50 = 83.58 and 83.52 µM, respectively). Moreover, the compounds demonstrated promising results as anti-inflammatory and analgesic agents with considerable ED50 values and gastric safety profiles. Remarkably, the most active COX inhibitors 6d and 11f possessed improved cardiovascular safety profiles, if compared to celecoxib, as shown by the laboratory evaluation of both essential cardiac biochemical parameters (troponin-1, prostacyclin, tumor necrosis factor-α, lactate dehydrogenase, reduced glutathione and creatine kinase-M) and histopathological studies. On the other hand, docking simulations confirmed that the newly synthesized compounds displayed sufficient structural features required for binding to the target COX-2 and sEH enzymes. Also, in silico ADME studies prediction and drug-like properties of the compounds revealed favorable oral bioavailability results. Collectively, the present work could be featured as a promising future approach towards novel selective COX-2 inhibitors with declined cardiovascular risks.

Five spectrophotometric methods for simultaneous determination of Amlodipine besylate and celecoxib in presence of its toxic impurity.

Five simple, selective and accurate spectrophotometric methods have been applied and developed for first time for simultaneous determination of amlodipine besylate (AML) and celecoxib (CEL) in presence of one harmful impurity, 4-methylacetophenone (MAP), in their ternary mixture without prior separation. Those spectrophotometric methods were developed and called: dual wave length in ratio spectra (DWRS), successive ratio-derivative spectra (SDR), modified absorption factor method (MAFM), modified amplitude center method (MACM) and first derivative -zero crossing coupled with amplitude factor method (FDAF). These methods include various steps using zero /or ratio /or derivative spectra and some mathematical techniques. Linear calibration curves were constructed over the concentration range of 2-100, 10-200 and 0.5-20 µg/mL for AML, CEL and MAP, respectively. High sensitivity with low LOD values 0.583, 3.118 and 0.147 for AML, CEL and MAP, respectively were obtained. Moreover, validation of the proposed methods was achieved according to ICH guidelines and satisfactory results were obtained indicating that the developed methods can be used for quality control analysis of AML and CEL concerning its impurity. No significant difference was observed when the obtained results of the developed methods were statistically compared with the reported HPLC method.

Validated green chromatographic methods for determination of amlodipine and celecoxib in presence of methylacetophenone.

Aim: Green, accurate and rapid methods, namely LC-MS/MS and thin layer chromatography-densitometric methods, were developed for determination of amlodipine besylate and celecoxib in presence of its process-related impurities, 4-methylacetophenone in pure and formulated tablets. Results: LC-MS/MS was achieved on ZORBAX Eclipse Plus C18 column using methanol:aqueous solution of 5 mM formic acid (95:5 v/v). High sensitivity with low limit of detection values 0.00028, 0.00027 and 0.0003 for amlodipine, celecoxib and 4-methylacetophenone, respectively were obtained. While, thin layer chromatography-densitometric was established using methanol:water:ammonia (70:25:1.5, by volume). Good linearity was obtained in the range of 0.1-10 µg/band, 1-150 µg/band and 0.01-2 µg/band for amlodipine, celecoxib and 4-methylacetophenone, respectively. Conclusion: The proposed method validation was achieved according to ICH guidelines. Those methods possess advantages of being ecofriendly methods which permit their application in quality control laboratories.

Discovery of novel urea-diarylpyrazole hybrids as dual COX-2/sEH inhibitors with improved anti-inflammatory activity and highly reduced cardiovascular risks.

Herein we describe our efforts to develop novel anti-inflammatory/analgesic agents devoid of known cardiovascular drawbacks. In doing so, two 1,5-diarylpyrazole series of urea linked (9a-f) and amide linked (11a-f) compounds were synthesized and evaluated in vitro as dual COX-2/sEH inhibitors using recombinant enzyme assays. The in vivo anti-inflammatory and analgesic activities were then examined using reported animal models. Compounds 9b and 9c showed the highest inhibitory activities against both COX-2 and sEH (IC50 of COX-2 = 1.85 and 1.24 µM; sEH = 0.55 and 0.40 nM, respectively), besides showing the best activity as anti-inflammatory agents. Interestingly, the cardiovascular profile of the two compounds 9b and 9c was evaluated through measuring some biochemical parameters such as prostacyclin (PGI2), lactate dehydrogenase (LDH), troponin-1 (Tn-1), tumor necrosis factor- α (TNF-α), creatine kinase-M (CK-M) and reduced glutathione (GSH) in addition to a histo-pathological study to investigate the changes in the heart muscle. The results confirmed that compounds 9b and 9c have a more favorable cardio-profile than celecoxib with much less cardiovascular risks associated with the common selective COX-2 inhibitors. Finally, the current work provided a promising approach that can be optimized to serve as a lead project to overcome the cardiovascular toxicity related to the traditional selective COX-2 inhibitors.

New substituted pyrazole derivatives targeting COXs as potential safe anti-inflammatory agents.

Aim: Everyday studies prove the increasing need for newer and safer agents to control cellular inflammatory response, an underlying cause for the pathophysiology of many other clinical cases. Results: Two newly designed sets of schiff 5a-h and chlacone 6a-f substituted pyrazoles were synthesized and evaluated for their in vivo/vitro anti-inflammatory activities. Most potent representatives were chosen for investigation of ulcerogenic and molecular docking properties. Conclusion: The synthesized compounds showed considerable edema inhibition percentage range if compared with celecoxib (13-93% and 58-93%, respectively) at different time intervals. Compound 6e showed the best screening results if compared with celecoxib (inhibition % = 93.62 and 93.51% at 5 h, COX-1/COX-2 selectivity index SI = 215.44 and 308.16 and ulcer index = 7.25 and 8, respectively).

Anti-inflammatory indomethacin analogs endowed with preferential COX-2 inhibitory activity.

Aim: The undeniable indomethacin potency has always suffered serious obstacles such as gastric damage. Continuous attempts to develop potent yet safe indomethacin analogs have never ceased. Results: Herein are new indole derivatives 4a-h and 5a-c, which were synthesized via Fisher indole reaction, evaluated for both their in vivo anti-inflammatory activities using rat paw edema method and their in vitro cyclooxygenase inhibitory activities. Then ulcerogenic liability, physicochemical parameters and molecular docking modeling were performed for the most potent ones. Conclusion: Promising results were obtained, where compound 4f was the best anti-inflammatory agent and preferential COX-2/COX-1 inhibitor (90.5% edema inhibition, selective index = 65.71, ulcer index = 7.3), if compared with indomethacin (86.7% edema inhibition, selective index = 0.079, ulcer index = 20.20).

Design, synthesis and anticancer evaluation of novel spirobenzo[h]chromene and spirochromane derivatives with dual EGFR and B-RAF inhibitory activities.

A novel series of spirobenzo[h]chromene and spirochromane derivatives was designed, synthesized and evaluated as potential anticancer agents against MCF-7 (human breast carcinoma), HT-29 (human colorectal adenocarcinoma) and A549 (human lung carcinoma) cell lines using MTT assay. Eight compounds 7, 8e, 13a-e and 16 showed a better anticancer activity than that of sorafenib, the multi-kinase inhibitor with IC50 values between 1.78 and 5.47 µM or erlotinib with IC50 values over 20 µM. Representative compounds 8e, 13c and 16 were selected for further mechanistic investigation via EGFR, B-RAF and tubulin polymerization assays. Compound 16 was the most potent EGFR inhibitor (IC50 = 1.2 µM), yet compounds 8e, 13c and 16 displayed moderate tubulin polymerization inhibition effects. Molecular docking studies of those compounds revealed their possible binding modes into the active sites of both EGFR and B-RAF kinases. The newly developed compounds represent a therapeutically promising approach for the treatment of different types of cancer.

Quantitative Determination of Synthesized Genotoxic Impurities in Nifuroxazide Capsules by Validated Chromatographic Methods.

Two accurate, selective, and precise chromatographic methods, namely TLC-densitometric and reversed-phase (RP)-HPLC, were developed and validated for the simultaneous determination of nifuroxazide (NIF) and its four synthesized impurities, which are also reported to be its related substances in the range of 10-100 µg/band and 10-100 µg/mL for NIF in the TLC and RP-HPLC methods, respectively. The developed TLC-densitometric method depended on the separation and quantitation of the studied components on silica gel 60 F254 TLC plates. Ethyl acetate-acetone-methanol-ammonia (85 + 25 + 5 + 0.5, v/v/v/v) was used as the developing system, and the separated bands were UV-scanned at 230 nm. On the other hand, the developed RP-HPLC method depended on chromatographic separation using a C8 column at 25°C and an aqueous solution of 0.1% sodium lauryl sulfate-acetonitrile as the mobile phase delivered according to the gradient elution program. Factors affecting the developed methods were studied and optimized. Also, method validation was carried out according to International Conference on Harmonization guidelines. The proposed methods were successfully applied for the determination of the studied drug in its bulk powder and in its pharmaceutical formulation. The developed methods showed no significant difference when compared with the reported RP-HPLC one. Their advantage is being the first stability-indicating methods for NIF and its genotoxic impurities.

Novel diphenylthiazole derivatives with multi-target mechanism: Synthesis, docking study, anticancer and anti-inflammatory activities.

Over the last few decades, a growing body of studies addressed the anticancer activity of NSAIDs, particularly selective COX-2 inhibitors. However, their exact molecular mechanism is still unclear and is not fully investigated. In this regard, a novel series of compounds bearing a COXs privilege scaffold, diphenyl thiazole, was synthesized and evaluated for their anticancer activity against a panel of cancer cell lines. The most active compounds 10b, 14a,b, 16a, 17a,b and 18b were evaluated in vitro for COX-1/COX-2 inhibitory activity. These compounds were suggested to exert their anticancer activity through a multi-target mechanism based on their structural features. Thus, compounds 10b and 17b with the least IC50 values in MTT assay were tested against three known anticancer targets; EGFR, BRAF and tubulin. Compounds 10b and 17b showed remarkable activity against EGFR with IC50 values of 0.4 and 0.2µM, respectively and good activity against BRAF with IC50 values of 1.3 and 1.7µM, respectively. In contrast, they showed weak activity in tubulin polymerization assay. The in vivo anti-inflammatory potential was assessed and interestingly, compound 17b was the most potent compound. Together, this study offers some important insights into the correlation between COXs inhibition and cancer treatment. Additionally, the results demonstrated the promising activity of these compounds with a multi-target mechanism as good candidates for further development into potential anticancer agents.

Design, synthesis and analgesic/anti-inflammatory evaluation of novel diarylthiazole and diarylimidazole derivatives towards selective COX-1 inhibitors with better gastric profile.

The inhibition of gastric cyclooxygenase 1 (COX-1) enzyme was believed to be the major cause of non-steroidal anti-inflammatory drugs (NSAIDs)-induced gastric ulcer. Recent studies disproved this belief and showed that the gastric tissues vulnerability is not solely connected to COX-1 inhibition. This work aimed at exploring and rationalizing the differential analgesic and anti-inflammatory activities of novel selective COX-1 inhibitors with improved gastric profile. Two novel series of 4,5-diarylthiazole and diarylimidazole were designed, synthesized in analogy to selective COX-1 inhibitors (mofezolac and FR122047) which lack gastric damaging effects. The new compounds were evaluated in vitro for their COXs inhibitory activity and in vivo for their anti-inflammatory and analgesic potentials. Four compounds; diphenylthiazole glycine derivatives (15a, 15b) and diphenylimidazolo acetic acid derivatives (19a, 19b), which possess carboxylic acid group exhibited significant activity and selectivity against COX-1 over COX-2. Of these compounds, (4,5-bis(4-methoxyphenyl)thiazol-2-yl)glycine 15b was the most potent compound against COX-1 with an inhibitory half maximal concentration (IC50) of 0.32µM and a selectivity index (COX-2 IC50/COX-1 IC50) of 28.84. Furthermore, an ulcerogenicity study was performed where the tested compounds demonstrated a significant gastric tolerance. Interestingly, the most selective COX-1 inhibitor showed higher analgesic activity in vivo as expected compared to their moderate anti-inflammatory activity. This study underscores the need for further design and development of novel analgesic agents with low tendency to cause gastric damage based on improving their COX-1 affinity and selectivity profile.

Novel pyrazolopyrimidine derivatives targeting COXs and iNOS enzymes; design, synthesis and biological evaluation as potential anti-inflammatory agents.

A novel set of 4-substituted-1-phenyl-pyrazolo[3,4-d]pyrimidine and 5-substituted-1-phenyl-pyrazolo[3,4-d]pyrimidin-4-one derivatives were synthesized and evaluated as potential anti-inflammatory agents. The newly prepared compounds were assessed through the examination of their in vitro inhibition of four targets; cyclooxygenases subtypes (COX-1 and COX-2), inducible nitric oxide synthase (iNOS) and nuclear factor kappa B (NF-κB). Compounds 8a, 10c and 13c were the most potent and selective ligands against COX-2 with inhibition percentages of 79.6%, 78.7% and 78.9% at a concentration of 2 µM respectively, while compound 13c significantly inhibited both COX subtypes. On the other hand, fourteen compounds showed high iNOS inhibitory activities with IC50 values in the range of 0.22-8.5µM where the urea derivative 11 was the most active compound with IC50 value of 0.22 µM. Most of the tested compounds were found to be devoid of inhibitory activity against NF-kB. Moreover, almost all compounds were not cytotoxic, (up to 25 µg/ml), against a panel of normal and cancer cell lines. The in silico docking results were in agreement with the in vitro inhibitory activities against COXs and iNOS enzymes. The results of in vivo anti-inflammatory and antinociceptive studies were consistent with that of in vitro studies which confirmed that compounds 8a, 10c and 13c have significant anti-inflammatory and analgesic activities comparable to that of the control, ketorolac. Taken together, dual inhibition of COXs and iNOS with novel pyrazolopyrimidine derivatives is a valid strategy for the development of anti-inflammatory/analgesic agents with the probability of fewer side effects.

Synthesis, anti-inflammatory and ulcerogenicity studies of some substituted pyrimido[1,6-a]azepine derivatives.

New series of pyrimido[1,6-a]azepines were prepared through reaction of the key amino compound 4 with various reagents to give a variety of 3-N-substituted amino derivatives 5-13. The synthesized compounds included the Mannich bases 5a-c, the formimidic acid ester 6, the phenylformamidines 7a-c, the benzylidine amino derivatives 8a-c, the acetic acid derivatives 9, 10a-c and 11, the carbamoylformates 12a,b and the amides 13a,b. All compounds were screened for their anti-inflammatory activity using the carrageenan-induced paw oedema in rats using diclofenac sodium as reference drug. In addition, ulcer indices for the most active compounds were calculated. Compounds 3, 4, 8a,c, 11 and 12a,b showed activity similar to or higher than diclofenac sodium with no or minimal gastric ulceration. The most active compound with no ulcerogenic effect is the amino derivative 4 (IC 50 = 6.61 mmol/kg).