Design, synthesis and anti-inflammatory assessment of certain substituted 1,2,4-triazoles bearing tetrahydroisoquinoline scaffold as COX 1/2-inhibitors.

Aiming to discover effective and safe non-steroidal anti-inflammatory agents, a new set of 1,2,4-triazole tetrahydroisoquinoline hybrids 9a-g, 11a-g and 12a-g was synthesized and evaluated as inhibitors of COX-1 and COX-2. In order to overcome the adverse effects of highly selective COX-2 and non-selective COX-2 inhibitors, the compounds of this study were designed with the goal of obtaining moderately selective COX-2 inhibitors. In this study compounds 9e, 9g and 11f are the most effective derivatives against COX-2 with IC50 values 0.87, 1.27 and 0.58 µM, respectively which are better than or comparable to the standard drug celecoxib (IC50 = 0.82 µM) but with lower selectivity indices as required by our goal design. The results of the in vivo anti-inflammatory inhibition test revealed that compounds 9e, 9g and 11f displayed a higher significant anti-inflammatory activity than celecoxib at all-time intervals. In addition, these compounds significantly decreased the production of inflammatory mediators PGE-2, TNF-ɑ and IL-6. Compounds 9e, 9g and 11f had a safe gastric profile compared to indomethacin, also compound 11f (ulcerogenic index = 1.33) was less ulcerous than the safe celecoxib (ulcerogenic index = 3). Moreover, histopathological investigations revealed a normal architecture of both paw skin and gastric mucosa after oral treatment of rats with compound 11f. Furthermore, molecular docking studies were performed on COX-1 and COX-2 to study the binding pattern of compounds 9e, 9g and 11f on both isoenzymes.

Experimental design optimization of simultaneous enantiomeric separation of atenolol and chlorthalidone binary mixture by high-performance liquid chromatography using polysaccharide-based stationary phases.

In this work, enantiomeric separation of a drug combination of two chiral drugs, namely, atenolol and chlorthalidone, is described. Prior investigation of the effect of different variables on the resolution of the enantiomers' peaks and the total run time represented by the retention time of the last eluted peak was conducted using face-centered composite design. Twenty-two experiments were carried out by varying the chiral stationary phase type as a categorical factor and mobile phase composition including the percentage of ethanol and percentage of diethylamine as continuous factors. According to the optimization process, a mobile phase consisting of hexane:ethanol:DEA:TFA (60:40:0.2:0.1%, v/v/v/v) pumped at flow rate 1 ml min-1 onto Lux-Cellulose 2 stationary phase was applied for the chiral separation and quantification of the drug combination at 230 nm. Application of the developed method to the pharmaceutical formulation of this combination was successfully performed, and satisfactory percentage of recoveries was obtained. The method was also fully validated following International Conference on Harmonization (ICH) guidelines. This method could be of high value and relevance for application in quality control laboratories.

Synthesis, molecular modeling studies, and anticonvulsant evaluation of novel 1-((2-hydroxyethyl)(aryl)amino)-N-substituted cycloalkanecarboxamides and their acetate esters.

A series of 1-((2-hydroxyethyl)(aryl)amino)-N-substituted cycloalkanecarboxamides IXa-l and their acetate esters Xa-l were designed and synthesized as new anticovulsant agents. The evaluation of the anticonvulsant effect was performed in vivo by subcutaneous pentylenetetrazole (scPTZ) and maximal electroshock (MES) tests in mice. Further, neurotoxicity, hepatotoxicity, and acute toxicity were determined. All the new candidates displayed 100% anticonvulsant activity in the scPTZ screen in the dose range of 0.0057-0.283 mmol/kg. The most potent compounds in the scPTZ screen were Xh (ED50 = 0.0012 mmol/kg), Xd (ED50 = 0.002 mmol/kg), Xf (ED50 = 0.004 mmol/kg), IXj (ED50 = 0.0047 mmol/kg), Xl (ED50 = 0.0076 mmol/kg), and Xi (ED50 = 0.008 mmol/kg). They exhibited higher fold activity in the anticonvulsant potential than the gold standards, phenobarbital and ethosuximide. Compound Xf was active in both scPTZ and MES screens. It showed ED50 of 0.016 mmol/kg in MES screen. In the neurotoxicity screens, none of the test compounds displayed any minimal motor impairment at the maximum administered dose. The 3D pharmacophore model using Biova 1 Discovery Studio 2016 programs exhibited high fit value. The anticonvulsant evaluation results were compatible with the molecular modeling study.

Structure-retention relationship for enantioseparation of selected fluoroquinolones.

Fluoroquinolones are popular class of antibiotics with distinct chemical functionality. Most of them are ampholytes with one chiral center. Stereogeneic center is located either in the side ring of Gatifloxacin (GFLX) or in the quinolone core of Ofloxacin (OFLX). These two amphoteric fluoroquinolones have terminal amino groups in common. The unusual Nadifloxacin (NFLX) is an acidic fluoroquinolone with a core chiral center. Owing to chirality and functionality differences among GFLX, OFLX, and NFLX, we mapped these enantiomers onto structure-retention relationship. Amount of acetic acid modifier was studied in screened mobile phase and cellulose tris(3-chloro-4-methyl phenyl carbamate) (Lux cellulose-2) stationary phase. Experimental design of acetic acid% along with column temperature have been applied. Resolution and enantioselectivity have been related to structural features of the studied enantiomers. High amount of acid (0.4%) was optimum for the separation of either side chirality with a proximate amino group (GFLX) or core chirality without basic functionality (NFLX), while low amount (0.2%) is optimum for core chiral center with distal amino group (OFLX). Temperature has no significant effect on resolution and retention of enantiomers except for OFLX. Enantio-retention explains possible chiral selective and nonselective interactions. The proposed methods have been validated for pharmaceutical analyses.

Enantioseparation of Substituted 1, 3-Diazaspiro [4.5]Decan-4-Ones: HPLC Comparative Study on Different Polysaccharide Type Chiral Stationary Phases.

Enantioseparation of substituted 1,3-diazaspiro[4.5]decan-4-ones (1-14) was achieved using different polysaccharide type chiral stationary phases (CSPs), namely, Chiralcel OJ, Chiralcel OD and Lux-Amylose-2 using different mobile phases which were either n-hexane/2-propanol or n-hexane/ethanol mixtures of various ratios (v/v) at flow rate 1 mL min-1. UV detection was carried out at 254 nm and temperature of 20°C. The retention behavior and selectivity of these CSPs were examined in isocratic normal phase high-performance liquid chromatography mode. The results revealed that the amylose CSP (Lux-Amylose-2) could separate almost all the compounds under investigation in contrast to cellulose CSPs (Chiracel OJ and Chiracel OD) which resolved fewer compounds.

Design, synthesis and antibacterial potential of 5-(benzo[d][1,3]dioxol-5-yl)-3-tert-butyl-1-substituted-4,5-dihydropyrazoles.

A series of 5-(benzo[d][1,3]dioxol-5-yl)-3-tert-butyl-1-substituted-4,5-dihydropyrazole derivatives 4a-e and 6a-g have been synthesized and spectrally characterized. The antibacterial activity of the novel candidates has been screened using the agar diffusion test. These compounds were endowed with high antibacterial activity against different Gram +ve and Gram -ve bacteria when compared with standard antibacterial drugs. In the light of zone of inhibition and MIC results, Sarcina and Staphylococcus aureus are the most sensitive bacteria where pyrrolidinomethanone derivative 4e showed MICs at 80 and 110 nM, respectively. While hydroxypiperidinoethanone derivative 6c showed MIC at 90 nM for Sarcina.

Anticonvulsant profiles of certain new 6-aryl-9-substituted-6,9-diazaspiro-[4.5]decane-8,10-diones and 1-aryl-4-substituted-1,4-diazaspiro[5.5]undecane-3,5-diones.

Synthesis and anticonvulsant potential of certain new 6-aryl-9-substituted-6,9-diazaspiro[4.5]decane-8,10-diones (6a-l) and 1-aryl-4-substituted-1,4-diazaspiro[5.5] undecane-3,5-diones (6m-x) are reported. The intermediates 1-[(aryl)(cyanomethyl)amino] cycloalkanecarboxamides (3a-f) were prepared via adopting Strecker synthesis on the proper cycloalkanone followed by partial hydrolysis of the obtained nitrile functionality and subsequent N-cyanomethylation. Compounds 3a-f were subjected to complete nitrile hydrolysis to give the respective carboxylic acid derivatives 4a-f which were cyclized under mild conditions to give the spiro compounds 5a-f. Ultimately, compounds 5a-f were alkylated or aralkylated to give the target compounds 6a-i and 6m-u. On the other hand, compounds 6j-l and 6v-x were synthesized from the intermediates 5a-f through alkylation, dehydration and finally tetrazole ring formation. Anticonvulsant screening of the target compounds 6a-x revealed that compound 6g showed an ED50 of 0.0043 mmol/kg in the scPTZ screen, being about 14 and 214 fold more potent than the reference drugs, Phenobarbital (ED50 = 0.06 mmol/kg) and Ethosuximide (ED50 = 0.92 mmol/kg), respectively. Compound 6e exhibited an ED50 of 0.019 mmol/kg, being about 1.8 fold more potent than that of the reference drug, Diphenylhydantoin (ED50 = 0.034 mmol/kg) in the MES screen. Interestingly, all the test compounds 6a-x did not show any minimal motor impairment at the maximum administered dose in the neurotoxicity screen.

Anticonvulsant potential of certain new (2E)-2-[1-Aryl-3-(1H-imidazol-1-yl)propylidene]-N-(aryl/H)hydrazinecarboxamides.

Anticonvulsant potential and neurotoxicity of certain new imidazole-containing arylsemicarbazones 6a-p are reported. The test compounds 6a-p exhibited anticonvulsant activity mainly in the scPTZ screen. Compound 6p emerged as the most active surrogate displaying 100% protection at a dose level of 636 µ mol/kg in the scPTZ screen without any neurotoxicity. The assigned (E)-configuration of the title compounds 6a-p was confirmed via single crystal X-ray structure of compound 6g.

Riluzole: validation of stability-indicating HPLC, D1 and DD1 spectrophotometric assays.

A stability-indicating reversed-phase high-performance liquid chromatographic assay procedure has been developed and validated for riluzole in the presence of alkaline and oxidative degradation products. The liquid chromatographic separation was achieved and compared isocratically on C18 Zorbax ODS and Poroshell 120 EC-C18 columns by using a mobile phase containing methanol-water, pH = 3.10 (70:30, v/v), at a flow rate of 1 mL/min and ultraviolet detection at 264 nm. The method was linear over the concentration ranges of 20-200 µg/mL (r = 0.9997) and 10-200 µg/mL (r = 0.9995). The limit of detection and quantitation for the two columns were 2 and 6 µg/mL and 1 and 3 µg/mL, respectively. Moreover, spectrophotometric methods were applied for the determination of riluzole in the presence of its oxidative degradation products by using first derivative spectrophotometry at 252.5 and 275.0 nm. The method was linear over the concentration range of 1-20 µg/mL (r = 0.9995 and 0.9996) at the studied wavelengths, with limits of detection and quantitation of 0.1 and 0.3 µg/mL. In addition, the first derivative ratio spectrophotometry (DD1) method was applied for the determination of riluzole in the presence of its alkaline degradation product at 252.0, 278.5 and 306.3 nm by using 100 µg/mL of alkaline degraded riluzole as a divisor; riluzole was additionally determined in the presence of its hydrogen peroxide oxidative degradation products at 252.5, 275.0 and 305.0 nm by using 200 µg/mL of oxidative degraded riluzole as a divisor. The DD1 method was linear over the concentration range of 1-20 µg/mL (r = 0.9996, 0.9995 and 0.9996 for the alkaline degradation product at the three studied wavelengths, respectively; and r = 0.9995, 0.9996 and 0.9995 for the oxidative degradation product at the three studied wavelengths, respectively), with limits of detection and quantitation of 0.1 and 0.3 µg/mL for both alkaline and oxidative degradation products. The two studied chromatographic and spectrophotometric methods were comparable and display the required accuracy, selectivity, sensitivity and precision to assay riluzole in bulk and pharmaceutical dosage forms. Degradation products resulting from the stress studies did not interfere with the detection of riluzole, which indicates that these are stability-indicating assays.

N-Phenyl-2-(propan-2-yl-idene)-hydrazine-carboxamide.

In the title compound, C(10)H(13)N(3)O, the hydrazinecarboxamide N-N-C(=O)-N unit is nearly planar [maximum deviation = 0.018 (2) Å] and is inclined at a dihedral angle of 8.45 (10)° with respect to the plane of the phenyl ring. The mol-ecular structure is stabilized by an intra-molecular C-H⋯O hydrogen bond which generates an S(6) ring motif. In the crystal, mol-ecules are linked into an inversion dimer by pairs of N-H⋯O and C-H⋯O hydrogen bonds.

Design and synthesis of novel stiripentol analogues as potential anticonvulsants.

A series of stiripentol (STP) analogues namely, 2-[(1E)-1-(1,3-benzodioxol-5-yl)-4,4-dimethylpent-1-en-3-ylidene]-N-(aryl/H)hydrazinecarboxamides 7a-h, (±)-(5RS)-N-(aryl/H)-(1,3-benzodioxol-5-yl)-3-tert-butyl-4,5-dihydro-1H-pyrazole-1-carboxamides (±)-8a-h, and (±)-[(5RS)-(1,3-benzodioxol-5-yl)-3-tert-butyl-4,5-dihydro-1H-pyrazol-1-yl](aryl)methanones (±)-13a-f was synthesized by adopting appropriate synthetic routes and was pharmacologically evaluated in the preliminary anticonvulsant screens. The selected bioactive new chemical entities were subjected to ED(50) determination and neurotoxicity evaluation. The most active congeners are 7h in MES screen and (±)-13b in scPTZ screen which displayed ED(50) values of 87 and 110 mg/kg, respectively, as compared to that of STP (ED(50) = 277.7 and 115 mg/kg in MES and scPTZ, respectively).

A cyclohexanecarboxamide derivative with inhibitory effects on Schistosoma mansoni cercarial serine protease and penetration of mice skin by the parasite.

A cyclohexanecarboxamide derivative, N-phenyl-N-[1-(piperidine-1-carbonyl)cyclohexyl] benzamide (MNRC-5), was evaluated for its inhibitory effects on Schistosoma mansoni cercarial serine protease activity and cercarial penetration. MNRC-5 exerted an inhibitory effect on S. mansoni cercarial serine protease at serial concentrations of the specific chromogenic substrate Boc-Val-Leu-Gly-Arg-PNA for such enzyme family and the inhibitory coefficient (Ki) value was deduced. Moreover, topical treatment of mice tails with the most potent inhibitory concentration of MNRC-5 formulated in jojoba oil successfully blocked cercarial penetration as demonstrated by a significant reduction (75%; p < 0.05) in the recovered S. mansoni worms from treated mice in comparison to control ones whose tails were painted with jojoba oil base containing no MNRC-5. In addition, the IgM and IgG reactivities to crude S. mansoni cercarial, worm and egg antigens were generally lower in sera from treated infected mice than untreated infected mice. In conclusion, we report on a new serine protease inhibitor capable for blocking penetration of host skin by S. mansoni cercariae as measured by lowering worm burden and decrease in the levels of both IgM and IgG towards different bilharzial antigens upon topical treatment.

A validated HPLC method for separation and determination of promethazine enantiomers in pharmaceutical formulations.

A simple, rapid, and validated method for separation and determination of promethazine enantiomers was developed. Promethazine was separated and quantitated on a Vancomycin Chirobiotic V column (250 x 4.6 mm), using a mixture of methanol, acetic acid, and triethylamine (100:0.1:0.1%, by volume) as a mobile phase at 20 degrees C and at a flow rate of 1 mL/min. The UV-detector was set to 254 nm. Acetyl salicylic acid (Aspirin) was used as an internal standard. The applied HPLC method allowed separation and quantification of promethazine enantiomers with good linearity (r > .999) in the studied range. The relative standard deviations (RSD) were 0.29 and 0.36 for the promethazine enantiomers with accuracy of 100.06 and 100.08. The limit of detection and limit of quantification of promethazine enantiomers were found to be 0.04 and 0.07 microg/mL, respectively. The method was validated through the parameters of linearity, accuracy, precision, and robustness. The HPLC method was applied for the quantitative determination of promethazine in pharmaceutical formulations.