DOS in chemistry

Antibacterial and antifungal agents are widely used in the management of infectious disease but most of them have developed resistance to micro-organism. To overcome this problem and to lower the side effects, many approaches can be utilized. Benzophenone derivatives are reported to have the broad spectrum of biological activities. In the present study we have screened benzophenone derivatives 5a-k against six bacterial species viz gram positive (Bacillus subtilis and Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa, Salmonella typhi, Proteus vulgaris, Shigella flexneri) bacteria. Also compounds 5a-k were tested with six fungal species viz (Candida albicans, Aspergillus niger, Fusarium solani, Aspergillus flavus, Botrytis cinerea, Candida krusei). The obtained results showed that the synthesized compounds 5a-k exhibited moderate to good activities against all the tested strains. Compounds 5a, 5c, 5d, 5f and 5g have shown good antibacterial and antifungal activities against selected strains.

were reported earlier. The antioxidant properties of these compounds 6a-e and 7a-e were evaluated by DPPH, nitric oxide and hydrogen peroxide radical scavenging methods. The investigation of antioxidant screening revealed that some of the tested compounds showed good to moderate antioxidant activity. Interestingly, the results show that the compounds containing electron releasing groups like methyl and methoxy exhibit good activities. In the above set of compounds 7e, 6e and 6d have shown very good antioxidant activity.

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Microorganisms are closely associated with the health and welfare of human beings. Whereas some microorganisms are beneficial, others are detrimental. Bacterial infections often produce inflammation and pains and in some instances, infections result in high mortality. Any subtle change in the drug molecule, which may not be detected by chemical methods, can be revealed by a change in the antimicrobial activity and hence microbiological assays are very useful. A series of substituted hydroxy benzophenones and benzophenone-N-ethyl morpholine ethers were screened for their antibacterial and antifungal activities. Antibacterial activity against S. aureus, E. aerogenes, M. luteus, K. pneumonia, and S. typhimurium, S. paratyphi-B and P. vulgaris bacterial strains and antifungal activity against C. albicans, B. cinerea, M. pachydermatis, C. krusei fungal strains were carried out. The bioassays indicated that most of the synthesized compounds showed potential antibacterial and antifungal agents.

The chiral N-D-ribosylnitrones 5-10 have been synthesized in four steps respectively, in the fourth step, D-ribosyloxime (4) condensed with substituted benzaldehyde in cool condition. The heterocyclization of Z-nitrone 6 with substituted Narylmaleimide by 1,3-dipolar cycloaddition were afforded new heterocyclic system of isoxazolidine derivatives 11-16 and 11'-16' as a mixture of diastereoisomers, the new isoxazolidines 11-16 have been separated purely and characterized by 1 H NMR, mass spectra and elemental analysis.

A series of novel piperazine analogues bearing quinolin 8 yloxy butan 1 ones/pyridin 2 yloxy ethanones were synthesized by a simple and convenient approach based on various substituted piperazine incorporating quinoline and pyridine moieties. The analogues were evaluated for in vitro antioxidant activity against 2,2 diphenyl 1 picrylhydrazyl (DPPH) and ferrous ion radical scavenging activities and anti inflam matory activity by inhibition of Vipera russelli venom (PLA 2 ) and gastric K + /H + ATPase activities. Most of the title compounds exhibited promising activity. Best antioxidant and PLA 2 inhibiting activities were found for piperazine analogues with phenyl and nitro phenyl groups, whereas methoxy group on phenyl piperazine indicated selectivity for the H + /K + ATPase.

A series of oxadiazole derivatives possessing morpholine 6a-l were synthesized by nucleophilic substitution reaction of key intermediates [1,3,4]-oxadiazole-2-thiol derivatives 5a-l with 4-(2-chloroethyl) morpholine. Compounds 6a-l were evaluated for their in vitro and in vivo antitumor potential in Dalton's Lymphoma Ascites (DLA) tumor cells. Among 6a-l series, compound 6a with concentration $8.5 lM have shown extensive cytotoxicity in vitro and 85% reduction in tumor volume in vivo, attributing an excellent anti-proliferative capability towards the cancer cells. Compound 6a has extensively inhibited the Microvessel Density (MVD) or tumoral neovasculature which was evident from the CD31 immuno staining and peritoneal H&E staining. The major reason for the antiproliferative activity of compound 6a was due to the repression of tumor vasculature.

A series of benzophenones possessing pyridine nucleus 8a–l were synthesized by multistep reaction sequence and evaluated for antiproliferative activity against DLA cells by in vitro and in vivo studies. The results suggested that, compounds 8b with fluoro group and 8e with chloro substituent at the ben-zoyl ring of benzophenone scaffold as well as pyridine ring with hydroxy group exhibited significant activity. Further investigation in mouse model suggests that compounds 8b and 8e have the potency to activate caspase activated DNase (endonuclease) which is responsible for DNA fragmentation, a primary hallmark of apoptosis and thereby inhibits the Dalton's lymphoma ascites tumour growth.

A novel series of benzoic acid N 0-[2-(4-benzothiazol-2-yl-piperazin-1-yl)-acetyl]-hydrazides 6a–j were synthesized and characterized by IR, 1 H, 13 C NMR, elemental and mass spectral analyses. The in-vitro cytotoxicity and cell viability assay of the synthesized compounds 6a–j were evaluated against Dalton's lymphoma ascites (DLA) cells. Our results showed that compound 6c with a bromo group on phenyl ring has showed promising antiproliferative efficacy. Further investigation of compound 6c on in-vivo treatment model depicts the increased tumor suppression through inhibition of angiogenesis.

LC separation of carboprost diastereomers in bulk drug was developed and validated using normal-phase amylose stationary phase Chiralpak AD-H. The effect of the organic modifiers, namely 2-propanol and ethanol in the mobile phase was optimized in order to obtain the best separation. The retention time of (R)-carboprost and (S)-carboprost were 15.3 and 17.1 min, respectively. Calibration curves were linear over the range of 0.2-1.0%, with the regression coefficient (R 2 ) of 0.9997. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.07 and 0.2%, respectively. The method was accurate, precise and suitable to use for the purpose of controlling unwanted (R)-isomer in the carboprost active pharmaceutical ingredient. This method can be successfully applied to the analysis of chiral purity of carboprost in pharmaceutical bulk drug samples.

Titrimetric and spectrophotometric methods are described for the determination of oxcarbazepine (OXC) in bulk drug and in tablets. The methods use N-bromosuccinimide (NBS) and bromopyrogallol red (BPR) as reagents. In titrimetry (method A), an acidified solution of OXC is titrated directly with NBS using methyl orange as indicator. Spectrophotometry (method B) involves the addition of known excess of NBS to an acidified solution of OXC followed by the determination of the unreacted NBS by reacting with BPR and measuring the absorbance of the unreacted dye at 460 nm. Titrimetry allows the determination of 6-18 mg of OXC and follows a reaction stoichiometry of 1 : 1 (OXC : NBS), whereas spectrophotometry is applicable over the concentration range of 0.8-8.0 μg mL −1 . Method B with a calculated molar absorptivity of 2.52 × 10 4 L mol −1 cm −1 is the most sensitive spectrophotometric method ever developed for OXC. The optical characteristics such as limits of detection (LOD), quantification (LOQ), and Sandell's sensitivity values are also reported for the spectrophotometric method. The accuracy and precision of the methods were studied on intraday and interday basis. The methods described could usefully be applied to routine quality control of tablets containing OXC. No interference was observed from common pharmaceutical adjuvants. Statistical comparison of the results with a reference method shows an excellent agreement and indicates no significant difference in accuracy and precision. The reliability of the methods was further ascertained by recovery studies in standard addition procedure.

Two simple, fast, accurate and precise methods for the determination of six phenothiazines and a number of their pharmaceutical formulations are described. The titrimetric method involves the oxidation of the drugs by metavanadate in sulphuric acid medium and titration of vanadium(IV) formed, with cerium(IV) using ferroin indicator and acetone as catalyst. In spectrophotometry, vanadium(IV) formed was reacted with ferriin and the resulting ferroin measured at 510 nm. Phenothiazines in the ranges 5±100 mg and 2.5± 25.0 mg mL À1 can be determined by titrimetry and spectrophotometry, respectively, with detection limits of 0.96±2.05 mg and 0.0359±0.0565 mg mL À1 , respectively. Both methods were applied successfully to the determination of the studied drugs in pharmaceutical preparations. The reliability of the assays was established by parallel determination by the of®cial methods of British Pharmacopoeia and the results being statistically evaluated.

Two simple titrimetric methods have been developed for the determination of hydroxyzine dihydrochloride (HDH) in pure form and in tablets. The principle of the methods are simple acid-base reactions in which the hydrochloride content of the drug was determined by titrating with an aqueous standardized NaOH solution either visually using phenolphthalein as indicator (method A) or potentiometrically using glass-calomel electrode system (method B). The methods were applicable over the range of 2-20 mg HDH. The procedures were also applied for the determination of HDH in its dosage forms and the results were found to be in good agreement with those obtained by the reference method. The precision, expressed by intra-day and inter-day relative standard deviation values, was satisfactory (RSD ≤ 2.76%). The accuracy was satisfactory as well (RE ≤ 2.67%). Excipients used as additives in pharmaceutical formulations did not interfere in the proposed procedures as shown by the recovery study via a standard addition technique with recovery percentage in the range 97.48-106.3% with a standard deviation of 1.76-3.42 %.

A simple, rapid, and extractive spectrophotometric method was developed for the determination of some postsynaptic α-1 adrenoreceptor antagonists: doxazosin mesylate (DOX), terazosin (TRZ) and alfuzosine HCl (ALF) in pure forms and pharmaceutical formulations. The developed methods are based on the formation of yellow colored chloroform ion-pair complexes between the basic nitrogen of the drugs and dyes, namely: bromocresol green (BCG), bromothymol blue (BTB), methyl orange (MO) and alizarine red S (ARS), in acidic buffer of pH range 3.0-5.0. The formed complexes were extracted with chloroform or dichloromethane and measured at 418, 414, 425 and 426 nm for DOX, at 419, 415, 425 and 428 nm for TRZ and at 418, 412, 421 and 427 nm for ALF using BCG, BTB, MO and ARS, respectively. The analytical parameters and their effects on the reported systems are investigated. Beer's law was obeyed in the range 1.0-130 µg mL −1 with correlation coefficient (n = 6) ≥ 0.9991. The molar absorpitivity, Sandell sensitivity, detection and quantification limits were also calculated. The composition of the ion associates was found 1:1 by Job's method. The proposed methods have been applied successfully for the analysis of the studied drugs in pure forms and in pharmaceutical formulations with percentage recoveries ranging from 99.18-100.61. The results of the analysis were validated statistically. The results were in good agreement and compared with those obtained with reported methods.

Three rapid, selective and sensitive spectrophotometric methods have been proposed for the quantitative determination of levocetirizine dihydrochloride (LCT) in pure form as well as in its pharmaceutical formulation. The methods are based on the charge transfer complexation reaction of LCT as n-electron donor with 2,4-dinitrophenol (DNP), picric acid (PA) as p-acceptors and iodine (I 2 ) as r-acceptor to give highly colored radical anion species. The colored products were quantified spectrophotometrically at 420 nm with both DNP (method A) and PA (method B) and at 375 nm with I 2 (method C). Under the optimized experimental conditions, Beer's law is obeyed over the concentration ranges of 1.2-24, 1.6-32 and 2.4-48 lg mL À1 LCZ for method A, method B and method C, respectively. The values of molar absorptivity, Sandell sensitivity, limits of detection and quantification are also reported. The effect of reaction medium, reaction time and reagent concentration on the sensitivity and stability of the complexes formed has been examined. The proposed methods were successfully applied to the determination of LCT in pure form and commercial tablets and in syrup with good accuracy and precision. Statistical comparison of the results was performed using Student's t-test and F-ratio at 95% confidence level and the results showed no significant difference between the reference and proposed methods with regard to accuracy and precision. Further to the accuracy and reliability the methods were confirmed by recovery studies via the standard addition technique.

A simple, selective and cost effective spectrophotometric method has been described for the determination of olanzapine (OLP) in bulk drug and in tablets. The method involves treating OLP with an excess of iodate in acid medium followed by the determination of liberated iodine by reacting with a fixed amount of Nile blue and measuring the absorbance at 400 nm. In this method, the amount of iodine reacted corresponds to the OLP concentration. The experimental conditions for the assay have been optimized and the absorbance is found to increase linearly with the concentration of OLP (r = 0.997). Beer's law is obeyed over the range 15-120 µg mL -1 . The calculated molar absorptivity and Sandell sensitivity values are 0.657×10 3 l mol -1 cm -1 and 0.475 µg cm -2 , respectively. The limits of detection (LOD) and quantification (LOQ) are 3.93 and 11.90 µg ml -1 . The performance of the method was validated according to the present ICH guidelines. The repeatability and intermediate precision, expressed by the RSD was better than 3%. The accuracy of the method expressed as relative error was satisfactory. The proposed method was applied to the analysis of tablet form of OLP and the results tallied well with the label claim. No interference was observed from concomitant substances normally added to tablets. The results were statistically compared with those of a literature method by applying the Student's t-test and F-test. The accuracy and validity of the method were further ascertained by performing recovery studies via spike method.

Two simple, rapid, reliable and cost-effective methods based on titrimetry in non-aqueous medium are described for the determination of olanzapine in pharmaceuticals. In these methods, the drug dissolved in the glacial acetic acid was titrated with the acetous perchloric acid with visual and potentiometric end point detection, crystal violet being used as the indicator for visual titration. The methods are applicable over 1-15 mg range of olanzapine. The procedures were applied to determine olanzapine in pharmaceutical products and the results were found to be in a good agreement with those obtained by the reference method. Associated pharmaceutical materials did not interfere. The precision results, expressed by inter-day and intra-day relative standard deviation values, were satisfactory, higher than 2%. The accuracy was satisfactory as well. The methods proved to be suitable for the analysis of olanzapine in bulk drug and in tablets. The accuracy and reliability of the methods were further ascertained by recovery studies via a standard addition technique with percent recoveries in the range 97.51-103.7% with a standard deviation of less than 2%.