2011 : Volume 3 : Issue 4

Methylation technique used for the identification of seed polysaccharide structure from Cassia hirsuta Linn. plant

Water soluble seeds polysaccharide was extracted from Cassia hirsuta Linn. plant by acid hydrolysis with sulphuric acid and identification by column and paper chromatographic analysis to be composed of D-galactose and D-mannose in 1:4 molar ratio. Methylation studies of seeds polysaccharide were carried out by Hakomari’s and Purdie’s method and its Infrared spectroscopy indicated that the polysaccharide was a galactomannan. D-mannose residues linked with (1®4)-β type on main polymer chain while D-galactose and D-mannose residues with (1®6)-α type linkages at non-reducing end. Methylated galactomannan on acid hydrolysis with sulphuric acid gave certain medicinal chemicals like methyl sugars as: 2, 3, 4, 6- tetra-Omethyl- D-galactose; 2,3,6-tri-O-methyl-D-mannose and 2,3-di-O-methyl-D-mannose is 1:3:1 molar ratio. On the basis of above finding methylation results a tentative polysaccharide structure has been proposed for the water soluble Cassia hirsuta Linn. seeds.

Method development and validation for simultaneous estimation of Paracetamol and Etoricoxib in pharmaceutical dosage form by RP-HPLC method

A RP-HPLC method was developed for simultaneous estimation of Paracetamol and Etoricoxib tablet formulation using Phenomenex Luna C18 column (250 mm × 4.6 mm id, 5 μm particle size) and a mobile phase of methanol : water (70:30 v/v), at flow rate 1.0 ml/min with UV detection at 235 nm. The retention time (tR) of Paracetamol and Etoricoxib found to be 3.07 and 5.72 min respectively. The proposed method was validated for system suitability, specificity, linearity, accuracy, precision, LOD, LOQ and robustness. All parameters were found to be within the acceptance limit. Linearity over the concentration range 5-30 μg/ml for both Paracetamol and Etoricoxib with regression coefficient (r2) 0.9998 and 0.9994 respectively. Limit of detection (LOD) found to be 0.10 μg/ml and 0.04 μg/ml whereas limit of quantitation (LOQ) found to be 0.33 μg/ml and 0.13 μg/ml for Paracetamol and Etoricoxib respectively. The accuracy of the proposed method was determined by recovery studies and found to be 99.74%- 101.25% and 99.08%-99.21% for Paracetamol and Etoricoxib respectively.

Alternative synthesis of Valsartan via Negishi coupling

A highly efficient approach to the synthesis of valsartan is described. Directed ortho-metalation of 4,4-dimethyl-2-phenyl-4,5-dihydrooxazole provides the key organozinc intermediate for palladium catalysed biaryl coupling with methyl N-(4-bromobenzyl)-N-pentanoyl-L-valinate (aryl bromide) obtained from alkylation of methyl N–pentanoyl-L-valinate. This methodology overcomes many of drawbacks associated with previously reported syntheses.

Synthesis, characterisation and pharmacological activities of 1-acetyl/propyl- 3-aryl-5-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-2-pyrazolines

Aseries of 1-acetyl/propyl-3-aryl-5-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-2-pyrazolines were synthesized in one step by condensing suitably substituted propenones, hydrazine and acetic/propionic acid. The newly synthesized compounds were screened for their analgesic and anti-inflammatory activity and most of the compounds showed significant activity comparable with that of the standard drug.

Isolation and characterization of triterpenoids and fatty acid ester of triterpenoid from leaves of Bauhinia variegata

Indian traditional medicinal plant Bauhinia variegata were extracted with ethanol and fractionated successively with petroleum ether (60 – 80°C), chloroform, n-butanol and methanol. The preliminary phytochemical studies of ethanolic extract of plant material showed the presence of carbohydrate, protein, glycosides, triterpenoids, saponins and steroids. The detailed phytochemical investigation of petroleum ether fraction of ethanolic extract of this plant isolated three triterpenoids and a fatty acid ester of triterpenoid, which were identified by spectroscopical analysis as α- amyrin caprylate, Lupeol, nor-α-amyrin and 3β, 28-di hydroxyl olean-12-enyl-palmitate, respectively.

Synthesis, properties and biological activity of thiophene: A review

Thiophene nucleus has been established as the potential entity in the largely growing chemical world of heterocyclic compounds possessing promising pharmacological characteristics. The similar compounds synthesized through different routes bear variable magnitudes of biological activities. The knowledge of various synthetic pathways and the diverse physicochemical parameters of such compounds draw the especial attention of medicinal chemists to produce combinatorial library and carry out exhaustive efforts in the search of lead molecules. The present review provides a broad view of the synthesis and properties of compounds having thiophene nucleus.

Synthesis and antimicrobial activities of some new pyrazole derivatives

Chloro acetyl and Acetyl pyrazoline derivatives have been synthesised by the condensation of pyrazoline derivatives (obtained by the reaction of various chalcones with hydrazine hydrate) with chloroacetyl chloride and glacial acetic acid respectively. The structures of new compounds were established on the basis of elemental IR and H1NMR data, the compounds were evaluated for their antibacterial activities.

Development and validation of a RP-HPLC Method for Simultaneous Estimation of Atenolol and Nitrendipine in Tablet Dosage Form

A rapid high performance liquid chromatographic method has been developed and validated for the estimation of Atenolol and Nitrendipine simultaneously in combined dosage form. A Phenomenox C-18 column having dimensions of 4.6×250 mm and particle size of 5 μm in isocratic mode, with mobile phase containing a mixture of methanol: acetonitrile: water (40:40:20 v/v) (pH adjusted to pH 3.0 using orthophosphoric acid) was used. The mobile phase was pumped at a flow rate of 1.5 ml/min and the eluents were monitored at 235 nm. The selected chromatographic conditions were found to effectively separate Atenolol (R t: 2.61 min) and Nitrendipine (R t: 6.11 min) having a resolution of 11.097. The method was validated in terms of linearity, accuracy, precision, and specificity, limit of detection and limit of quantitation. Linearity for Atenolol and Nitrendipine were found in the range of 30-70 μg/ml and 6-14 μg/ml, respectively. The percentage recoveries for Atenolol and Nitrendipine ranged from 99.05- 100.51% and 99.14-101.60%, respectively. The limit of detection and the limit of quantitation for Atenolol were found to be 1.96 μg/ml and 5.95 μg/ml respectively and for Nitrendipine were found to be 0.34 μg/ml and 1.03 μg/ml, respectively. The method was found to be robust and can be successfully used to determine the drug content of marketed formulations.

Effect of Dielectric constant on Protonation Equilibria of Glycylglycine in Aqueous Solutions of propylene glycol and Dioxan

Knowledge of the protonation constants of dipeptides is important and necessary for complete understanding of their physiochemical behaviour. In this study, the protonation constants of glycylglycine were studied in propylene glycol and dioxan-water mixtures (0 - 60% v/v) at 303.0 ± 0.1 K at an ionic strength of 0.16 M using pH-metric technique. The protonation constants were calculated with the computer program MINIQUAD75 and selection of the best fit chemical models is based on the statistical parameters. The effect of solvent on protonation constants was discussed based on electrostatic forces operating on the protonation equilibria. Distribution of species, protonation equilibria and effect of influential parameters on the protonation constants have also been presented.

Solute–Solvent Dielectric Effects on PAM 120

Quantum-chemical solvent effect theories describe the electronic structure of a molecular subsystem embedded in a solvent or other molecular environment. The solvation of biomolecules is important in molecular biology .In this theoretical study, we focus on a kind of dammarane sapogenins (PAM120). This molecule optimized in various solvent media such as heptan, carbontetrachloride, toluene, tetrahydrofurane, dichloroethane, ethanol, methanol, dimethylsulfoxide and water using the self-consistent reaction field model. This process depends on either the reaction potential function of the solvent or charge transfer operators that appear in solute-solvent interaction. We performed nonempirical quantum-mechanical calculations at the HF/3-21G, 6-31G , 6-31G*,6-31G** and B3LYP/6-31G** levels of theory in the gas phase and some solvents at 298K.We studied energy ,dipole moment ,charge and so on.

Poly(4-vinylpyridine)isopentyl bromide based selective electrode with PVC matrix in aqueous media

A selective PVC-membrane based on “poly(4-vinylpyridine)isopentyl bromide” as a carrier is tested as an ion sensor. This sensor reveals a linear response towards Br-, Cl-, I-, IO3 - and NO3 - ions in the concentration range (10-4 - 10-1 M. The potentiometric behaviour of the electrode is independent of the pH in test solutions with a slope near 59 mV per decade in middle in the range 4 < pH < 9. The electrode possesses a satisfactory reproducibility and a fast response time.

Isotherms and batch kinetics of the biosorption of cadmium onto pre-treated tridax procumbens

The ash obtained from Tridax procumbens leaves was used to adsorb cadmium from aqueous solution of Cadmium chloride. The sorption process with respect to its metal ion concentration, pH, contact time and particle size on adsorption were studied. The percentage removals with respect to the parameters were also studied. The most effective pH range was found to be 5.8-6.0 for sorption of metal ions. The first order rate equation by Lagergren was tested on the kinetic data and the adsorption process followed first order rate kinetics. Isotherms data were analyzed for possible agreement with Langmuir and Freundlich adsorption isotherms; the model for dynamics of metal ions uptake proposed in this work fitted the experimental data reasonably well for Freundlich adsorption isotherm than Langmuir adsorption isotherm. The correlation coefficients (R2) were 0.998 and 0.912 for Freundlich and Langmuir isotherms respectively.

Synthesis, characterization and ion-exchanging properties of novel oligomeric azo dyes

The oligomaric azo dye based on 3-amino-phenol-Formaldehyde (APF) polymer was prepared by diazotization of Aniline and coupling with 3-amino-phenol-Formaldehyde(AP) resin. The AAPF was then treated with 5-chloromethyl-8-hydroxyquinoline hydrochloride in the presence of a THF in conc. NaOH (PH 9-10) at room temperature for 7 hrs. The resultant oligomaric ligand designated as azopolyphenol-Formaldehyde-5-chloromethyl-8-hydroxyquinoline (AAPFHQ) was characterized by elemental analysis, IR spectral studies, and thermogravimetry. The polymeric metal chelates of AAPF-HQ with Cu2+, Zn2+, Mn2+, Ni2+, UO2 2+ and Co2+ metal ions were prepared and characterised by metal:ligand ratio, IR and reflectance studies, magnetic properties, thermogravimetry and microbicidal activity. The AAPF-HQ sample was also monitored for its chelating and ion-exchanging properties. Batch equilibration method has been adopted, for evalution of ion-exchange properties.

A new processfor the synthesisof enantiomerically pure R-(+)-Npropargyl- 1-aminoindan mesylate (Rasagiline mesylate)

A new processdeveloped for the synthesis of enantiomerically pure R-(+)-N-propargyl-1- aminoindan mesylate(Rasagiline mesylate) by using K2HPO4/Triethylbenzylammonium chloride (TEBAC) as a reagent. This approach controls the formation of other isomerS-(-)-N-propargyl- 1-aminoindane. This new process may be useful for the preparation of enantiomerically pure Rasagiline mesylatein commercial scale with good yields.

Synthesis, characterisation and biological applications of conducting poly (p- amino phenol) and its nano compound

The oxidative chemical polymerizations of para aminophenol was synthesized in acidic medium using potassium dichromate as an oxidant at 00C and its nano compound was synthesized using an anionic surfactant Sodium Dodecyl Sulphate. They were characterized by FT- IR, UV-VIS, 1H-NMR, TGA, SEM and TEM. The formation of benzenoid and quinonoid structure was confirmed from the FT-IR, 1H-NMR and UV studies and the thermal studies confirms that the poly nano compound is more stable than the corresponding polymer. The conductance was measured and found to be semiconducting in nature. The resulting polymer and its nano compound were analyzed for its antioxidant activities using DPPH assay and the antibacterial activities by agar well cut diffusion method against two bacterial stains Staphylococcus aureus (gram +ve) and Escherichia coli (gram-ve). The antioxidant and antibacterial activities of poly (p–aminophenol) nano compound is greater than the corresponding polymer and they were concentration and the time dependant. The increased activities of poly nano compound may be due increase in surface area because of its smaller size and these properties can be considered in the field of biomaterials in biomedical areas.

Application of Beckmann rearrangement in the synthesis of indophenazino fused pyrrolo [3,2-c] azepine and pyrrolo [3,2-c] diazepine derivatives

A variety of ketoximes of indophenazino fused carbazole 5a and azacarbazoles 5(b-e), easily prepared from the corresponding ketones 4(a-e) undergo the Beckmann rearrangement upon treatment with 2,4,6-trichloro [1,3,5] triazine in N,N-dimethylformamide at room temperature afforded indophenazino fused pyrrolo [3,2-c] azepine (6a) and indophenazino fused pyrrolo [3,2-c] diazepines derivatives 6(b-e) in moderate to goog yields.

Various approaches for synthesis of some important benzothiaiazepines

Benzthiazepines are important group of 7- membered heterocyclics which posses hypertensive, cardiovascular, antipsychotic activities.

Development and optimization of RP-HPLC method for the estimation of s (-) amlodipine in tablet dosage form

S(-) amlodipine is a potent calcium channel blocker used for the treatment of hypertension, congestive heart failure and angina pectoris. S(-) amlodipine avoids the adverse effect of amlodipine in racemic mixtures. The RP-HPLC method developed for the estimation of s (-) amlodipine in tablet dosage form was done by fixing the parameters as Phenomenex C8 ODS column (150 x 4.6 mm), 5 m particle size with mobile phase 20 mM sodium dihydrogen phosphate buffer: acetonitrile (65: 35% v/v) adjusted to pH 8 was used. Mobile phase flow rate was maintained at 1.2ml/min and detected at 239nm. The retention time was 4.20± 0.02 minutes

Synthesis, characterization and spectral studies of metal (II) complexes derived from benzofuran-2-carbohydrazide and 2-acetylthiophene Schiff’s base

The complexes of the type MLCl2, where M = Cu(II), ML2.2H2O,where M = Co(II), Ni(II) and ML2, where M = Zn(II), Cd(II) and Hg(II), L = [BCAT] Schiff’s base derived from reaction between benzofuran-2-carbohydrazide with 2-acetylthiophene. The ligand acts as bidentate by coordinating through carbonyl oxygen and azomethine nitrogen atoms. Structures have been elucidated on the basis of elemental analysis, conductivity measurement, magnetic properties, spectral studies like IR, 1H NMR, ESR and electronic spectral studies. On the basis of spectral characterization we proposed tentative structures for all these complexes. The antibacterial and antifungal activities of the ligand and their metal complexes have been screened by MIC method.

2D QSAR Analysis on 5β-Methylprolyl-2-Cyanopyrrolidine Derivatives as DPP IV Inhibitors

Two dimensional quantitative structure activity relationship (2D QSAR) study was performed on 5β-methylprolyl-2-cyanopyrrolidine derivatives as dipeptidyl peptidase IV (DPP IV) inhibitors using molecular design suite software (VLifeMDS). This study was performed with 30 compounds (data set) using sphere exclusion (SE) algorithm, random and manual selection methods for the division of the data set into training and test set. Partial least square (PLS) linear regression analysis coupled with stepwise variable selection method was applied to derive QSAR models which were further validated for statistical significance by internal and external validation. The most significant model has squared correlation coefficient (r2), cross validated correlation coefficient (q2) and predictive correlation coefficient (pred_r2) 0.6231, 0.5109 and 0.3862 respectively. The QSAR model indicates that the descriptors T_C_O_4 [This is the count of number of Carbon atoms (single, double or triple bonded) separated from Oxygen atom (single or double bonded) by 4 bond distance in a molecule], SdssCE-index [Electrotopological state indices for number of carbon atom connected with two single bonds] and XlogP [This descriptor signifies ratio of solute concentration in octanol & water and generally termed as octanol water partition coefficient] contributing 48.19%, 28.93% and 22.88 % respectively. Negative coefficient value of T_C_O_4 and XlogP indicated that lower value leads to better dipeptidyl peptidase inhibitory activity whereas higher value leads to decrease activity whereas positive coefficient value of SdssCE-index indicated that higher value leads to good dipeptidyl peptidase inhibitory activity while lower value leads to reduced activity.

Validated HPTLC method for simultaneous estimation of Rabeprazole Sodium, Paraetamol and Aceclofenac in bulk drug and formulation

This paper describes a new, simple, precise, and accurate HPTLC method for simultaneous estimation of Rabeprazole sodium, Paracetamol and Aceclofenac as the bulk drug and in tablet dosage forms. Chromatographic separation of the drugs was performed on aluminum plates precoated with silica gel 60 F254 as the stationary phase and the solvent system consisted of toluene: ethyl acetate: methanol: acetic acid 6: 4: 0.8: 0.4 (v/v/v/v). Densitometric evaluation of the separated zones was performed at 256 nm. The three drugs were satisfactorily resolved with RF values 0.35 ± 0.5, 0.42 ± 0.3 and 0.57 ± 0.42 for Rabeprazole sodium, Paracetamol and Aceclofenac respectively. The accuracy and reliability of the method was assessed by evaluation of linearity 100–200 ng/spot for Rabeprazole sodium, 15–90 ng/spot for Paracetamol and 12-72 ng/spot for Aceclofenac., precision (intra-day RSD 1.66–1.87 % and inter-day RSD 1.48–1.60 % for Rabeprazole sodium , and intra-day RSD 1.03–1.74 % and inter-day RSD 0.53–1.59 % for Paracetamol similarly intra -day RSD 1.12–1.73 % and inter-day RSD 0.62–1.73 % for Aceclofenac ), accuracy (100.25 ± 0.12 % for Rabeprazole Sodium, 99.67 ±0.06 % for Paracetamol and 99.63 ± 0.18 % for Aceclofenac), and specificity, in accordance with ICH guidelines.

Copper oxide nanoparticles-catalyzed direct N-alkylation of amines with alcohols

This paper describes the direct N-alkylation of amines with alcohols through oxidation/imination/reduction sequence using a catalytic amount of nanocrystalline CuO as a recyclable catalyst and K2CO3 as the base in toluene at 110 °C. This method is found to be applicable for wide range of amines and alcohols. The operational simplicity and the mild reaction conditions add to the value of this method as a practical alternative to the N-alkylation of amines with alcohols.

RP-HPLC method for the determination of Valacyclovir in bulk and Pharmaceutical formulation

A reverse phase high performance liquid chromatography (RP-HPLC) has been developed for the estimation of valacyclovir in bulk drug and pharmaceutical dosage form. The quantification was carried out using C18 column and mobile phase consisting of 0.067 M phosphate buffer at pH 6.5: acetonitrile : methanol (70:20:10 % v/v), at flow rate of 0.5 mL/min. The separation was performed at ambient temperature. Eluents were monitored by UV detector set at 244 nm. The method was statistically validated for the linearity, precision, accuracy, LOD and LOQ. The linearity was found to be in the range of 5-30 μg/mL. The proposed method was found to be simple, precise, accurate, rapid, economic and reproducible for the estimation of valacyclovir in bulk drug and tablet.

Synthesis, computational studies and pharmacological evaluation of some acetamides as serotonin antagonists

New acetamides (4a-c) linked with coumarin fragment were synthesized by chloroacetylation of some aminothiazoles and further treating with 7-hydroxy-4-methylcoumarin in the presence of anhydrous potassium carbonate in acetonitrile. The target compounds (4a-c) were evaluated for antiserotonergic activity by 5-HTP induced head twitches behavior in mice. The physicochemical similarity of the target compounds with respect to clozapine was assessed by calculating from a set of physiochemical properties using software programs. Compound 4b demonstrated good similarity values with respect to the standard drug and has shown antiserotonergic activity.

Development and Validation of HPTLC method for Determination of Voriconazole in Human Plasma

Voriconazole is a new antifungal agent that is a derivative of fluconazole, having wide-spectrum activity and a fungicidal action against Candida and Aspergillus species. Voriconazole displays non-linear pharmacokinetics in adults but has linear pharmacokinetics in children. Interindividual variability is generally high; both in children and adults, and diverse manifestations of toxicity are possibly attributed to high drug concentrations. This indicates the need to monitor voriconazole concentration in plasma after oral dose. A simple, selective and sensitive high performance thin layer chromatographic method for the determination of voriconazole in human plasma is developed and validated. After precipitation of plasma proteins with acetonitrile, the protein-free supernatant was spotted on plates precoated with silica gel 60 F254. Cephalexin was used as an internal standard. The mobile phase consisted of a mixture of toluene : methanol : triethylamine in the ratio of 6:4:0.1 v/v/v. The drug showed considerable absorbance at 254 nm. The method was found to be linear over the concentration range of 50– 400 ng/band. Mean drug recovery was found to be 98.82%. Voriconazole in plasma samples was stable when stored for different stability conditions. The method was found to be precise and accurate and can further be extended for pharmacokinetic studies for therapeutic drug monitoring of voriconazole in routine clinical practice.

Synthesis of some new pyrrole derivatives and their antimicrobial activity

A new pyrrole derivatives of 5,5'-(3,5-dimethyl-1H-pyrrole-2,4-diyl)bis(1,3,4-oxadiazole-2- thiol)(3), 5,5'-(3,5-dimethyl-1H-pyrrole-2,4-diyl)bis(4-amino-4H-1,2,4-triazole-3-thiol)(4), 5,5’- (3,5-dimethyl-1H-pyrrole-2,4-diyl)bis(4H-1,2,4-triazole-3-thiol) (6), and 5,5'-(3,5-dimethyl-1Hpyrrole- 2,4-diyl)bis(1,3,4-thiadiazol-2-amine)(7) were prepared from cyclization methods. Synthesized compounds were confirmed by IR, 1H NMR, 13C NMR, mass spectral and elemental analysis. The reaction was performed by using ordinary condensation type, which enabled to easy work-up and good yield. Synthesized compounds (1-7) were screened for antimicrobial activity.

A new and alternate synthesis of Linezolid: An antibacterial agent

A New and alternate syntheses of Linezolid, an antibacterial agent are reported from by employing two different approaches and finalized the meritorious one. The key step in both the approaches involves N-alkylation of 3-fluoro-4-morpholinobenzenamine 3 with respective compounds by changing the leaving functionalities on other end and followed by functional group transformations yielded an antibacterial agent Linezolid. Among the both, later is more efficient one with respect to improved overall yield, easy process and less number of steps.

Molecular docking studies of quinoline-3-carbohydrazide as novel PTP1B inhibitors as potential antihyperglycemic agents

Binding modes of a series of quinoline-3-carbohydrazide as protein tyrosine phosphatase 1B (PTP 1B) inhibitors have been identified by molecular modeling techniques. We have performed docking and ADME predictions of these inhibitors with PTP 1B enzyme. As per our literature, we found that PTP1B is highly hydrophobic. The results indicate that quinoline-3- carbohydrazide for addition to hydrogen bonding interactions, Arg24, Asp48, Glu115, Lys116, Lys120, Cys215, Ser216, Ala217 amino acid residues of PTP 1B are responsible for governing inhibitor potency of the compounds. ADME predictions of 6 top selected compounds were done with Qikprop 3.2 tool available in Schrödinger 9.0 ver. The information generated from the present study should be useful in the design of more potent PTP1B inhibitors as antidiabetic agents.

Synthesis of 2,3-disubstituted thieno(2,3-d)pyrimidines for antibacterial and pharmacological activity

We have synthesized various substituted thieno(2,3-d)pyrimidines, first by synthesizing 2- aminothiophene-3-carboxamide(1), subsequently treating with chloroacetylchloride, 2- (chloroacetamido)thiophene-3-carboxamide(2) was obtained followed by cyclisation, 2- (chloromethyl)thieno(2,3-d) pyrimidine-4one(3) was obtained. The nucleophylic substitution of compound 2-(chloromethyl)thieno(2,3-d)pyrimidine-4one with various aromatic amines, aminophenol gives substituted thienopyrimidines(4a-j).The structure of new compounds were established on the basis of spectral and elemental analysis. The title compounds were screened for antibacterial (agar diffusion method) and antioxidant activity (DPPH scavenging method) and inhibition of denaturation of protein. Most of the compounds have shown promising activity.

RP-HPLC method for simultaneous estimation of Drotaverine hydrochloride and Aceclofenac in their combined tablet dosage form

Drotaverine hydrochloride and aceclofenac are prescribed for the treatment of adult patients with muscular pain associated with spasm. This study describes a rapid, simple, precise and accurate RP-HPLC method for simultaneous estimation of drotaverine hydrochloride and aceclofenac in their combined tablet dosage form. The separation was achieved on a Phenomenex-Gemini (150mm x 4.6mm, 5 μm) column with an isocratic mixture of methanol, acetonitrile and water in the ratio of 60:30:10, pH adjusted to 3.0, at a flow rate of 1.0 ml/min and UV detection at 298.5 nm. The retention time for drotaverine hydrochloride and aceclofenac was 1.06 and 4.19 min respectively. The method was linear in the range of 8-40 μg/ml and 10- 50 μg/ml for drotaverine hydrochloride and aceclofenac respectively. The correlation coefficients were 0.9997 for drotaverine hydrochloride and 0.9995 for aceclofenac. The method was validated as per ICH guidelines and successfully applied for estimation of drotaverine hydrochloride and aceclofenac in commercially available tablet dosage form.

Voltammetric-oxidation and Determination of 5-Flurouracil and its Analysis in Pharmaceuticals and Biological Fluids at Glassy Carbon Electrode Mediated by surfactant cetyltrimethyl ammonium bromide

The voltammetric oxidation and determination of 5-Fluorouracil 5-(FU) was studied at a glassy carbon electrode (GCE) in the presence of cetyltrimethyl ammonium bromide (CTAB) by cyclic and differential pulse voltammetry at pH-7. The results indicated that the voltammetric responses of 5-Flurouracil are drastically increased in the low concentration of CTAB, suggesting that CTAB exhibits observable enhancement effect to the determination of 5- Flurouracil. Under the optimal conditions the peak current was proportional to 5-Flurouracil concentration in the range of 2.0 x 10-8 to 6.0 x 10-7 M with detection limit of 20.13nM by differential pulse voltammetry. The proposed method was applied to the determination of 5- Fluorouracil in pharmaceuticals. The analytical performance of this sensor has been evaluated for detection of analyte in human serum and urine as real samples.

L-Cysteine methyl ester hydrochloride: A new corrosion inhibitor for copper in nitric acid

Potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS) and weight loss measurements were used to investigate the inhibitory effect of L-Cysteine Methyl Ester Hydrochloride (L-CMEH) on corrosion of copper in 2M HNO3 solution. The inhibitor showed > 97% inhibition efficiency at 10−3M. EIS results show that the change in the impedance parameters (Rt and Cdl) with concentration of L-Cysteine Methyl Ester Hydrochloride (LCMEH) is indicative of the adsorption of molecules leading to the formation of a protective layer on the surface of copper. Potentiodynamic polarization studies suggested that it is a mixed type inhibitor. The inhibitor studied reduces the corrosion rates. The results obtained from weight loss, polarisation, and impedance measurements are in good agreement.

Novel spectrophotometric method for the estimation of Nisoldipine in bulk and pharmaceutical dosage forms

A new, simple and sensitive spectrophotometric method in ultraviolet region has been developed for the determination of nisoldipine in bulk and in pharmaceutical formulations. Nisoldipine exhibits absorption maxima at 237 nm. Developed method obeyed the Beer’s law in the concentration range of 4 - 40 μg/mL. The method is accurate, precise and economical. The proposed method has been applied successfully for the analysis of the drug in pure and in its tablet dosage forms. In this method, there is no interference from any common pharmaceutical additives and diluents. The % recovery is greater than 99.86 – 100.67%, this shows that the method was free from the interference of excepients. The results of the tablet analysis were validated with respect to accuracy (recovery), linearity, limit of detection and limit of quantization were found to be satisfactory.

Kinetic spectrophotometric method for the estimation of cefixime in pharmaceutical formulations

The objective of the current study was to develop a simple, sensitive kinetic spectrophotometric method based on the oxidation of Cefixime using potassium permanganate in alkaline medium. The rate of change of absorbance was measured at 598 nm. The initial rate method and fixed time method (at 4 min) are utilised to construct calibration graphs for calculating the concentration of the drug. The results were validated through inter day and intraday precision assays according to the ICH guidelines and also through recovery studies. Statistical comparison of the proposed methods with that of reference method shows excellent agreement and indicates no significant difference in their accuracy and precision.

One pot synthesis of dihydropyrimidinones catalyzed by Cyanuric chloride: An improved procedure for the Biginelli reaction

We report herein the use of Cyanuric chloride as a new catalyst for the one-pot Biginelli reaction coupling of β-ketoester, aldehydes and urea (or thiourea) to afford the corresponding dihydropyrimidinones/thiones.

Synthesis, characterization and biological activities of Cd(II) complexes with hydrazide ligands

A series of new acid hydrazides have been synthesized by reaction of novel ligands Acetic acid (3- chloro – 4 – hydroxyl benzylidene )-hydrazide (A), Acetic acid (2 – nitro – benzaylidene )- hydrazide (B) with cadimium (II) bromide , These new complexes were characterized by elemental analysis, IR spectroscopy and UV spectral techniques. The changes observed between the FT-IR and UV-Vis spectra of the ligands and of the complexes allowed us to establish the coordination mode of the metal in complexes . The results suggest that the Schiff bases coordinate as univalent anions with their two dentate N, O donors derived from the carbonyl and azomethine nitrogen . This newly synthesized compounds have been tested against grampositive bacteria (Bacillus subtilis and Staphylococcus aureus) and gram-negative bacteria (E.coli and Salmonella typhi ) for their antibacterial activity.

Synthesis and structural studies on penta and hexa coordinated organotin (IV) complexes of alkyl pyruvate aroyl hydrazones

A series of five and six coordinated diorganotin(IV) complexes of the type R2Sn(L)n Cl2-n [R = butyl and phenyl, n = 1 or 2, HL = Schiff base derived from the condensation of methyl/ethyl pyruvate with substituted acid hydrazides [salicylhydrazide, p-toluic acid hydrazide and napthoic acid hydrazide] have been synthesized. The mode of bonding in the complexes has been suggested on the basis of analytical and spectroscopic techniques (IR, 1H, 13C and 119Sn NMR) spectra, where the ligands are coordinating to metal through oxygen and nitrogen of carbonyl and azomethine group respectively. The ligands and their organotin complexes have been tested for antimicrobial activity against phytopathogenic fungi Candida albicans, Aspergillus niger at 25±1°C and bacteria Bacillus subtilis, Escherichia coli and Staphylococcus aureus at 37±1°C compared with Tetracycline, Chloramphenicol, Kanamycin, Cefazolin Sodium, Cefotaxime as reference drugs. The activity of the ligands is enhanced on complexation.

Antimicrobial activity and thermal properties of copolymer resin derived from 2, 2’-dihydroxybiphenyl, dithiooxamide and formaldehyde

The copolymer (2, 2’-HBDF) synthesized by the condensation of 2, 2’-dihydroxybiphenyl (2, 2’- HB) and dithiooxamide (D) with formaldehyde (F) in the presence of acid catalyst and using 1:1:2 molar proportions of the reacting monomers. The copolymer possesses antimicrobial activity for certain bacteria such as Staphylococcus aureus, Escherichia coli, and fungi Aspergillus niger, Candida albicans. The thermogravimetric analysis of copolymer resin prepared in present study has been carried out by non-isothermal thermogravimetric analysis technique in which sample is subjected to condition of continuous increase in temperature at linear rate. Thermal study of the resin was carried out to determine its mode of decomposition and relative thermal stabilities. The Freeman-Carroll and Sharp-Wentworth methods have been used in the present investigation to calculate thermal activation energy and different kinetic parameter of the copolymer resins. The advantage of Freeman-Carroll method is to calculate both the order of reaction (n) and energy of activation in one single stage by keeping heating rate constant. By using data of thermogravimetric analysis, various thermogravimetric parameters like frequency factor (Z), entropy change (S), free energy change (F) and apparent entropy (S*) have been determined using Freeman-Carroll method.

Mixed ligand stability constants of Co (II), Ni (II), Cu (II) and Zn (II) transition metal complexes with chloropheniramine maleate drug and amino acids

Chemical equilibrium studies on Co (II), Ni (II), Cu (II) and Zn (II) transition metal complexes with chloropheniramine maleate drug (L) and a series of eight amino acids (R) have been investigated pH metrically at 270C temperature and 0.1 M ionic strength (NaClO4) in aqueous solution. The formation of various possible complex species has been evaluated by computer program and discussed in terms of various relative stability parameters.

Synthesis of N-isopropylphenoxypropanolamine analogue and their electrocatalysis for the determination of dopamine: A cyclic voltammetric study

1-(p-tolyloxy)-3-chloropropan-2-ol (TCPL) was prepared as an analogue to the Nisopropylphenoxypropanolamine and it was characterized by LCMS, 1H NMR and purity by HPLC. The prepared compound was used as a modifier for the electrochemical determination of dopamine (DA). The effect of scan rate, concentration and pH was studied. The overall electrode process was found to be both adsorption and diffusion controlled. The effect of concentration and pH was studied. The detection limit of DA at the modified electrode was found to be 4.5 X 10 -7 M.Hence this electrode can be used for the selective and sensitive determination of DA.

Development and validation of UV spectrophotometric method for the determination of Gliclazide in tablet dosage form

The article describes a simple, sensitive, rapid, accurate and precise spectrophotometric method for the estimation of gliclazide in bulk and pharmaceutical dosage forms. The wavelength maxima for gliclazide was found to be 229.5 nm with molar absorptivity of 1.4962×104l/mol/cm. Beer’s law was obeyed in the concentration range of 7-27 μg/ml. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.31 μg/ml and 0.92 μg/ml, respectively. The percentage recovery of the drug for the proposed method ranged from 98.68-100.12% indicating no interference of the tablet excipients. The results demonstrate that proposed method is accurate, precise, and reproducible while being simple and rapid too for the determination of gliclazide in tablet dosage form.

Synthesis, antimicrobial and anthelmintic activity of some novel benzimidazole derivatives

New benzimidazole derivatives containing 4-chloropyridine-2-carbonyl and N-methyl picolinamide moieties in one side chain at 1H position of benzimidazoles (2- ((benzylthio)methyl)-1H-benzo[d]imidazol-1-yl)(4-chloropyridin-2-yl)methanones(3) have been synthesized as depicted in scheme-1. The intermediates and final compounds were purified and their chemical structures have been confirmed by IR, 1H NMR, and Mass spectral data. All the derivatives were examined for their anthelmintic activity against Indian adult earthworms (pheretima posthuma) at various concentrations (0.2% and 0.5%), antibacterial activity against B.subtilis, B.cereus, S.epidermidis, S.typhi, P.aeruginosa and K.pneumoniae and antifungal activity against A.flavus, F.oxysporium and P.notatum at a concentration of 2mg/ml. Most of the compounds tested have shown promising activities when compared with the standard drugs.

Corrosion inhibition and adsorption properties of 3-amino-1,2,3- triazole on mild steel in H3PO4

The corrosion inhibition of 3-amino-1,2,3-triazole (ATA) on the mild steel in phosphoric acid solution was studied using the weight-loss method and potentiodynamic polarisation and EIS measurements. The addition of ATA decrease the corrosion rate (CR) and consequently the inhibition efficiency increases with concentration. Examination of polarization curves indicates that ATA acts as a mixed-type inhibitor. ATA retards also the cathodic reaction with changing the mechanism of the hydrogen evolution reaction only at 10-2 mol·L−1. The adsorption of ATA on the steel surface obeys Temkin isotherm adsorption model. The free enthalpy energy has been evaluated.

Development and validation of uv spectrophotometric method for estimation of dexibuprofen in bulk and dosage form

The aim of present work is to develop and validate simple, sensitive and specific spectrophotometric method for the determination of Dexibuprofen, a non-steroidal antiinflammatory drug (NSAID) in pure form and in pharmaceutical formulations. UV spectrophotometric method, which is based on measurement of absorption at maximum wavelength in phosphate buffer pH 6.8, was found to be at 221.8 nm by using 5% methanol. The developed method was validated with respect to linearity, accuracy (recovery), precision and specificity. The optimum conditions for analysis of the drug were established. The drug obeyed the Beer’s law and showed good correlation. Beer’s law was obeyed in concentration range 0-60 μg/ml having line equation y = 0.046x +0.017 with correlation coefficient of 0.999. The results of analysis were validated by recovery studies. The method was found to be simple, accurate, precise, economical and robust.

Synthesis and antimicrobial activity of some new isatins derivatives

Some new N-[3-(2-Oxo-1, 2-dihydro-indol-3-ylidene-hydrazinocarbonyl)-benzyl]-nicotinamide (III) have been synthesised from different isatin derivatives (I) by condensing with N-(3- hydrazinocarbonylbenzyl) nicotinamide (II). Their chemical structures have been confirmed by IR, 1H NMR, Mass and by elemental analysis. Investigation of antimicrobial activity of compounds was done by the disk diffusion technique. Among the compounds tested, the compound with 5-F, 5-CH3 substitution showed the most favourable antimicrobial activity.

Evaluation of in vivo antimutagenic potential of fruits extracts of Withania coagulans

Medicinal plants play an important role in development of drugs. The present study is based upon the Anti-mutagenic activity of Withania coagulans, a traditionally known herb. The Antimutagenic activity of Withania coagulans fruit extracts was investigated on cyclophosphamide induced micronucleus formation in mouse bone marrow cells. The results confirmed that a single i.p administration of W. coagulans fruit extract at the dose of 500, 1000 and 1500 mg/kg body weight prior to 24 hours have significantly prevented the micronucleus formation in dose dependent manner in bone marrow cells of mice as compared to cyclophosphamide group.

Synthesis and anti-cancer evaluation of cyclotriphosphazene hydrazone derivatives

Hexasubstituted cyclotriphosphazene hydrazones [N3P3(-OC6H4-p-CH=N-NH-C(O)-C6H4-p-X)6] were prepared by the reaction of hexachlorocyclotriphosphazene with N'-(4- hydroxybenzylidene)-4-substituted-benzohydrazides [HO-C6H4-p-CH=N-NH-C(O)-C6H4-p-X]. The structures were confirmed by elemental analysis, FT-IR, 1H, 13C, 31P NMR and mass spectrometry. These cyclic model systems bearing hydrolysable hydrazone linkages were evaluated for their antiproliferative activity in vitro against the human liver carcinoma cell line (HepG2) and Human cervix carcinoma cell line (HeLa).

Influence of Dielectric Constant on Complex Equilibria of L- dopa Complexes of Toxic Metal ions

Binary complexes of L-dopa with toxic metal ions such as Pb(II), Cd(II) and Hg(II) have been studied in 0.0-60.0% v/v 1,4 dioxan-water media at 303 K and an ionic strength of 0.16 mol dm- 3. The active forms of the ligand are LH3 +, LH2 and LH-. The best fit chemical models are arrived at based on firm statistical grounds employing crystallographic R-factor, χ 2, Skewness and Kurtosis. The predominant species formed are MLH+, ML2H2 and ML2H-. The stability constants of the binary systems decrease in the order Hg(II) > Cd(II) > Pb(II). The trend in variation of complex stability constants with change in the dielectric constant of the medium is explained on the basis of electrostatic and non-electrostatic forces. The species distribution with pH at different compositions of dioxan-water mixtures and plausible equilibria for their formation are also presented. The chemical speciation and bioavailability of the toxic metal ions is also described.

Synthesis and pharmacology of some novel 4(3H)-quinazolinone derivatives

Several novel 4(3H)-quinazolinone derivatives incorporating four known bioactive moiety such as adamantine, piperazine, imidazolidine and thiazolidinone were synthesized by using multistep reaction strategy. The synthesized derivatives were characterized by IR, 1H-NMR, Mass and elemental analysis. Furthermore the synthesized derivatives evaluated for antibacterial, antifungal, anti-inflammatory, ulcerogenic, analgesic and acute toxicity activities.

3d transition metal complexes of 3-hydrazino-benzoxazine-2-one: Synthesis, characterization and antifungal activity

A new series of Cr(III), Mn(II), Fe(II), Co(II) and Ni(II) complexes of the 3-hydrazino benzoxazine-2-one (HBO) were prepared and characterized. The ligand behaves as a bis bidentate ONNN donor. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, thermal, infrared, electronic spectra, magnetic susceptibility and conductivity measurements. An octahedral geometry was suggested for all the complexes. All the complexes show subnormal magnetic moments. The ligand, HBO, and its complexes were tested against Neurospora crassa, a non-pathogenic fungus. The Mn(II) and Co(II) complexes exhibited higher antifungal activities than the parent ligand.

Synthesis and characterization of some novel chromones and chromanones derivatives and its biological screening

Novel (3E)-3-[[4-(Aryl or Alkyl sulfonyl, Aryl carbonyl and Heteroaryl) piperazin-1-yl] methylene] chroman-4-one and N-[1-(Aryl or Alkyl sulfonyl, Aryl carbonyl and Heteroaryl) -4- piperidyl]-6-methyl-4-oxo-chromene-3-carboxamide were synthesized and identified by spectroscopic techniques like NMR, IR, MS and elemental analysis. Antibacterial study of the same derivatives were done using bacterial model like E. coli, P.aeruginosa, S. aureus, and S.Pyogenus and antifungal study of the same were carried out using Candida albicans, A. Niger and A.Clavatus. Results show that the compound having 3-chloropropane sulfonyl type linkage has shown good activity against the bacterial strains, while some of the derivatives have shown moderate improvement in activity against pathogenic strains.

Synthesis, structural and thermal characterization of a novel 3D FeIII Complex

Crystal structure and thermal stability of the hydrated crystals of the Glycine (the basic amino acid) and ammonium ferrous sulphate compound, Ammonium hexaaqua ferrate(iii) sulphate have been reported here. The title compound crystallized in the space group P21/c with Z = 2 and unit cell dimensions a = 6.2383(10) Å, b = 12.6076(19) Å, c = 9.2652(13) Å. In the title compound, FeH12O6.2(O4S).2(H4N), the FeIII atom exists in a octahedral coordination environment. Each Fe(H2O)6 complex anion is surrounded by four sulphate anion acceptor groups and four ammonium cation donor groups. The ions are held together by N—H···O and O—H···O hydrogen bonds into a layer network. Thermal behaviour of crystals has been investigated by TG/DTA analysis.

Synthesis of novel quinazolino-quinolones as potential antibacterial agents

Synthesis of novel quinozolono-quinolones from 3-quinazolinones coupled with N-1 position of 6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate with a two carbon chain linker and to evaluate the biological activities.

Detection of amino acids by LC-Mass spectroscopy from the leaves of Tabernaemontana divaricata

A small tree, Tabernaemontana divaricata has been mentioned in Ayurvedic medicinal systems mainly for the treatment of diarrhea and cancer. Detection of amino acids was carried out from various extracts of T. divaricata. The study of amino acids was carried out using LC-MS technique. The amino acids from the extracts were compared with the standard amino acids. Total three amino acids were detected in ethanol and acetone extracts. Majority of amino acids were detected in water extract. Keywords Tabernaemontana divaricata

Synthesis of some new pyrazolone derivatives as potent antimicrobial agents

Invasive microbial infections are major problems around the world, especially in immuno compromised patients. The recent expansion of antimicrobial drug research has occurred because there is a critical need for new antimicrobial agents to treat these life threatening invasive infections. In the present study three series of new substituted pyrazolone derivatives (5a-f, 6a-f and 8a,b) were synthesized by the Knoevenagel condensation reaction of pyrazolones (3a,b) with various substituted carbaldehydes (4a-f, 7). These newly synthesized compounds were characterized by IR, NMR, mass spectra and also by C, H, N analyses. New compounds were screened for their antimicrobial studies against S. aureus, B. subtilis, E. coli and P. aeruginosa. The results revealed that compounds 5c and 6c having 2,5-dichlorothiophene substituent showed significant antibacterial activity against all tested microorganisms as compared to the standard drug Ceftriaxone.

Facile acid catalyzed rearrangement of ethers to diarylmethanes

The acid catalyzed rearrangement of benzylphenolic ethers to biphenylmethane compounds is described.

Pharmaceutically fine synthesis and their study of antimicrobial activity of metal complexes with some schiff’s bases

In this newly approached method a novel series of transition metal complexes were synthesized by reactions with various Schiff base compounds such as 2,2.-{ethane-1,2-diylbis [nitrilo (E) methylylidene]} Diphenol, 2,2.-{propane-1,3-diylbis [nitrilo (E) methylylidene]} Diphenol, 2,2.- {1,3-phenylenebis [nitrilo(E) methylylidene]} Diphenol, 6,6'-((1E,1.E)-(propane-1,3-diylbis (azanylylidene)) bis(methanylylidene))bis(2,4-di-tertbutylphenol), 2-[(E)-(pyridin-2-ylimino) methyl] phenol, 2, 4-di-tert-butyl-6-[(E)-(pyridin-2-ylimino) methyl] phenol . Schiff base compounds were treated with transition metal ions of Ni2+, Co+2, Cr+2, Fe+3 and Cd2+. For current work different molar ratios of metals are used. These metal complexes were synthesized under maintained temperature at reflux condition within few hours. Such transition metal complexes of Schiff base compounds were characterized as IR, 1H-NMR, C, H, N and O and their antibacterial activity of metal complexes were studied. Simply these reactions shows bright path to new class of medicinally important compounds.

Azo dyes based on salicylic acid-formadehyde polymer as a polymeric ligands

Aniline was diazotized and coupled with Salicylic acid-Formaldehyde polymer and characterized duly. The ligand was designated as PSA and its metal chelates with Cu+2, Zn+2, Co+2, Fe3+, UO2 2+, Mn+2and Ni+2 metal ions were prepared. The PSA and its polymeric metal chelates were characterized by elemental analysis, spectral studies, thermogravimetry,diffuse reflectance spectral studies and magnetic susceptibilities. Chelation ion-exchanging properties of the polymers were also studied by empolying the batch equilibration method. All the samples have also been monitored for microbicidal activity.

Optimization and characterization of a thermo tolerant lipase from Cryptococcus albidus

A thermo tolerant yeast Cryptococcus albidus was characterized for optimal production of liapse . The organism shown maximum production on 5th day of incubation. The optimum temperature for both production and activity was 500C and optimal pH was 6.5. Few metal ions like Ba2+, Ca2+, Mg2+ and Zn2+ enhanced the activity whereas Fe3+, Mn2+ and Zn2+ declined the enzyme action. The enzyme was characterized by some inhibitors and solvents; amongst inhibitors, ? mercapto ethanol and SDS had shown maximum inhibition where as amongst the solvents phenol and choloroform strongly repressed the activity. Different solid and liquid raw materials viz; oil cake, vegetable oils and ghee extraction waste were also studied for enzyme production.

Synthesis and biological activities of N-[(2-Substituted phenyl)-1, 3-thiazol-5-one]-naphtho[2,1-b]furan-2-carboxamide derivatives

Peptic ulcer is an ulcer of the mucous membrane lining those parts of the alimentary tract exposed to digestive juices or a necrotic lesion characterized by a crater like erosion of the stomach wall (gastric ulcer) or the duodenum (duodenal ulcer) often associated with painful symptoms. Thiazole derivatives have been reported to possess antiulcer activity. With the view to study antiulcer, antibacterial and antitubercular activities, we have synthesized some new thiazole derivatives and screened them for the same. A mixture of 2-hydroxy-1-naphthaldehyde, ethyl bromoacetate and anhydrous potassium carbonate in dry acetone was heated under reflux for 24.35 hours and then filtered which yielded Naphthyl [2,1-b]furan-2-ethyl carboxylate which was mixed with hydrazine hydrate in ethanol and refluxed for 18.3 hours to yield Naphtho [2,1- b]furan-2-carbohydrazide. A solution of various substituted aldehydes in ethanol was added to a solution of naphtho[2,1-b]furan-2-carbohydrazide in DMF, refluxed for 8.2 hours poured into crushed ice and then filtered to give N-[Substituted benzylidene]- naphtho [2,1-b]furan-2- carboxamide which were dissolved in 1,4-dioxan, mercaptoacetic acid and zinc chloride was refluxed for 14.4 hours to yield N-[Substituted phenyl]- 1',3'-thiazol-5-one]-naphtho [2,1- b]furan-2-carboxamide. It was observed that among ten compounds synthesized only three compounds showed potent antiulcer activity. Only four compounds showed significant antibacterial activity. These compounds were further subjected for Antitubercular activity and all the four showed sensitivity at concentrations 50 and 100 ?g/ml.

General Unrestricted Structure Activity Relationships based evaluation of quinoxaline derivatives as potential influenza NS1A protein inhibitors

In present work, we have performed GUSAR analysis of quinoxaline derivatives, previously reported as potential influenza NS1A protein inhibitors. A robust, statistically sound and thoroughly validated consensus model is obtained. The four parametric model has following statistical characteristics R2 = 0.746, F = 12.897, SD = 0.283, Q2 = 0.645. GUSAR analysis provides idea regarding contribution of each atom in deciding binding with protein. The analysis could be very useful in designing better influenza NS1A protein inhibitors.