Shasun Research Center

Chennai, India

Shasun Research Center

Chennai, India
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Karthikeyan K.,Shasun Research Center | Karthikeyan K.,University of Madras | Shanmugasundaram P.,Shasun Research Center | Ramadhas R.,Shasun Research Center | Pillai K.C.,University of Madras
Journal of Pharmaceutical and Biomedical Analysis | Year: 2011

A sensitive and rapid ion chromatography (IC) method was developed for the low level determination of allylamine (AAM) in sevelamer (SVM) drug substances, i.e., sevelamer hydrochloride (SVH) and sevelamer carbonate (SVC). This method utilized a Dionex Ion Pack CS14 IC column, a mobile phase of 10mM methane sulfonic acid with conductivity detection. The total chromatographic run time was as short as 8min. The various factors involved in the sample preparation such as, extraction solvent, extraction time and stirrer speed were evaluated. This method was validated as per United States Pharmacopoeia (USP) and International Conference on Harmonization (ICH) guidelines in terms of detection limit, quantitation limit, linearity, precision, accuracy, specificity and robustness. Linearity of the method was very good over the concentration range of 9-750μg/mL with the coefficient of determination (r2) 0.999. The detection and quantitation limit of AAM were 2.7 and 9.0μg/mL, respectively. The recovery data obtained for AAM were between 97% and 109%. Also, the specificity of the method was proved through IC coupled with mass spectrometer (IC-MS). The developed method was found to be robust and applied successfully to determine the content of AAM in Sevelamer bulk drugs. © 2010 Elsevier B.V.


Karthikeyan K.,Shasun Research Center | Karthikeyan K.,University of Madras | Arularasu G.T.,Shasun Research Center | Murali V.,Shasun Research Center | Chandrasekara Pillai K.,University of Madras
Journal of Pharmaceutical and Biomedical Analysis | Year: 2011

This paper describes identification and characterization of a process-related impurity of meprobamate drug substance observed in HPLC-UV method. Forced degradation studies were carried out under acidic, basic, oxidation, light and thermal conditions to assess the nature of the impurity. The pure impurity was obtained by preparative LC isolation and analyzed by NMR and mass. Structural elucidation by spectral data and formation of this impurity were discussed in detail. The structure of the process-related impurity was established as carbamic acid-2-carbamoyloxymethyl-2-methyl-pent-3-enyl ester (olefin). Also, the relative response factor, linearity, detection limit (DL), quantitation limit (QL) and recovery were determined for meprobamate and the impurity. Good linearity was obtained for the impurity over the concentration range of 0.03-0.20% (w/w) with the coefficient of determination (r2) of 0.999. The DL and QL of olefin impurity were 0.0003 and 0.001% (w/w), respectively. The isolated impurity was co-injected with meprobamate sample to confirm the retention time in HPLC. © 2010 Elsevier B.V.


Karthikeyan K.,Shasun Research Center | Karthikeyan K.,University of Madras | Arularasu G.T.,Shasun Research Center | Ramadhas R.,Shasun Research Center | Pillai K.C.,University of Madras
Journal of Pharmaceutical and Biomedical Analysis | Year: 2011

A new chiral purity method was developed for d-cycloserine (d-cys) by reverse phase HPLC and validated. Chiral derivatizing reagents, viz., o-phthalaldehyde and N-acetyl-l-cysteine were utilized in this method. The resultant diastereomers were resolved using Zorbax SB Phenyl HPLC column under isocratic elution. A mobile phase of 95:05 (v/v), 20mM Na2HPO4 (pH 7), and acetonitrile, respectively, was used with the flow rate of 1.0mL/min and UV detection at 335nm. The method development with different chiral stationary phases and chiral derivatization reagents were also investigated. The stability of diastereomer derivative and influence of organic modifier and pH of the mobile phase were studied and optimized. The stability-indicating capability of the method was established by performing stress studies under acidic, basic, oxidation, light, humidity and thermal conditions. The detection and quantitation limit of l-cycloserine (l-cys) were 0.015 and 0.05% (w/w), respectively. A linear range from 0.05 to 0.30% (w/w) was obtained with the coefficient of determination (r2) 0.998. The recovery obtained for l-cys was between 92.9 and 100.2%. This method was applied successfully in pharmaceutical analysis to determine the content of l-cys in d-cys bulk drug. © 2010 Elsevier B.V.


Karthikeyan K.,Shasun Research Center | Karthikeyan K.,University of Madras | Balaji T.S.,Shasun Research Center | Shanmugasundaram P.,Shasun Research Center | Chandrasekara Pillai K.,University of Madras
Journal of Chromatographic Science | Year: 2010

The purpose of this study is to develop and validate a simple, sensitive, and robust high-performance liquid chromagraphic (HPLC) method for the determination of impurities ca. 2-methyl-2-propyl-1,3-propane diol (MP0) and 2-hydroxymethyl-2-methyl pentyl carbamate (MP1) in meprobamate (MEP) drug substance with refractive index (RI) detection. This method utilizes a Zorbax Eclipse XDB C18 HPLC column, a mobile phase of 80:20 (v/v) 10 mM KH2PO4,-acetonitrile, respectively. The stability-indicating capability of the method has been established by performing stress studies under acidic, basic, oxidation, light, humidity, and thermal conditions. The major degradation products of acid and base hydrolysis are identified as MP0 and MP1. The recovery data obtained for impurities are between 96.0-109.8%. The detection and quantitation limits of this method ranges from 0.009 to 0.017 mg/mL and 0.029 to 0.055 mg/mL, respectively. The relative standard deviation (RSD) for the area at QL is less than 6.1%. Good linearity (r2 > 0.99) and precision (RSD < 2.2%) have been obtained for MEP, MP0, and MP1. This method has been applied successfully to determine the content of impurities in MEP bulk drug.


Perumal K.,Shasun Research Center | Perumal K.,Annamalai University | Garg J.A.,University of Zürich | Blacque O.,University of Zürich | And 5 more authors.
Chemistry - An Asian Journal | Year: 2012

The synthesis, photophysical, and electrochemical attributes of a novel class of boron difluorides containing an aromatic-fused alicyclic/hetero- alicyclic ring built on a β-iminoenamine chromophoric backbone are reported. The compounds displayed large Stokes shifts (86-121 nm), and were emissive in the solid state. The quantum yields obtained in solution at room temperature were unusually lower by an order of magnitude compared to those in the solid state. Some of the tested compounds displayed aggregation-induced emission (AIE). Single crystal XRD analyses revealed a lack of interplanar π-π interactions, which are presumed to be absent owing to non-planarity of the alicyclic component in the molecule. For most of the studied compounds, time-dependent DFT (TD-DFT) calculations invariably reveal intramolecular charge transfer (π-π*) characteristics with the frontier orbitals concentrated on the boron-nitrogen heterocycle. The participation of boron and fluorine atoms was found to be negligible. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Kumaran E.,Shasun Research Center | Santhi M.,Shasun Research Center | Balasubramanian K.K.,Shasun Research Center | Bhagavathy S.,Shasun Research Center | Bhagavathy S.,B.S. Abdur Rahman University
Carbohydrate Research | Year: 2011

Montmorillonite K-10 clay-catalyzed substitution reactions of 3,4,6-tri-O-alkyl-2-C-hydroxymethyl-Dglycals, 3,4,6-tri-O-acetyl-D-glycals, 3,4,6-tri-O-alkyl-D-glycals, and 3,4-(dihydro-2H-pyran-5-yl)methanol with a few alcohols and phenols are described. The reactions of 2-C-hydroxymethyl-D-glycals with phenols were similar to those of 2-C-acetoxymethyl-D-glycals and afforded pyrano[2,3-b]benzopyrans. This montmorillonite K-10 clay-catalyzed transformation is facile both under ambient (Method 1) and microwave conditions (Method 2). Ferrier rearrangement of 3,4-(dihydro-2H-pyran-5-yl)methanol with p-cresol, 2,6-xylenol, and ethanol led to totally unexpected transformations. Reaction of 2-C-hydroxymethyl- D-galactal with 2,6-dimethylphenol in the presence of montmorillonite K-10 led to a novel domino transformation affording 4-(5',6'-dihydro-4H-pyran-3'-ylmethyl)-2,6-dimethylphenol. In contrast, 3,4,6-tri-O-acetyl-D-glucal furnished the Ferrier rearrangement product, 2,6-dimethylphenyl 4,6-di-Oacetyl- 2,3-dideoxy-α-D-erythro-hex-2- enopyranoside. Also, isomerization of 3,4,6-tri-O-alkyl-D-glycals to products of allylic rearrangement, 2,3-unsaturated-O-glycosides in good yields is reported. © 2011 Elsevier Ltd. All rights reserved.


Koch M.,University of Zürich | Perumal K.,Shasun Research Center | Perumal K.,Annamalai University | Blacque O.,University of Zürich | And 5 more authors.
Angewandte Chemie - International Edition | Year: 2014

Design of highly efficient phosphorescent emitters based on metal- and heavy atom-free boron compounds has been demonstrated by taking advantage of the singlet fission process. The combination of a suitable molecular scaffold and appropriate electronic nature of the substituents has been utilized to tailor the phosphorescence emission properties in solution, neat solid, and in doped PMMA thin films. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Petrus A.J.A.,Kanchi Mamunivar Center for Post Graduate Studies Autonomous | Bhuvaneshwari N.,Kanchi Mamunivar Center for Post Graduate Studies Autonomous | Alain J.A.L.,Shasun Research Center
Indian Journal of Natural Products and Resources | Year: 2011

Indigenous leafy vegetables of the traditional rural communities are potentially nutritious and contain a vast array of beneficial phytochemicals that offer protection against several chronic and age-related human ailments. The present study was planned to assess the antioxidative constitution of the fresh leaves of Mukia maderaspatana (Linn.) M. Roem. (Family: Cucurbitaceae). The total phenolic, flavonoid, carotenoid and vitamin E contents were determined using specific spectrophotometric methods and the amount of ascorbic acid by titrimetry. The medicinal leafy vegetable was found to be a good dietary source of the low molecular weight antioxidants analysed. The leaf extract exhibited potent in vitro antioxidant/radical scavenging (ABTS•+ and FRAP assays) and metal (Ferrous ion) chelating activities and also inhibited β-carotene bleaching. Saponarin has been isolated and determined as the major phenolic antioxidant by HPLC. The amount of phenolics (292.392 ±1.087 mg GAE), flavonoid (247.079 ± 0.705 QE), carotenoids (0.812 ± 0.075 mg), vitamins C (17.046 ± 0.839 mg) and E (0.194 ± 0.068 mg) and saponarin (220.800 ± 0.944 mg) present and the antioxidant capacities (301.926 ± 0.869 mg vitamin C equivalent antioxidant capacity) are reported for 100 g of fresh leaves. The protective/therapeutic significance of these antioxidant components is also highlighted.


Tudhope S.R.,Shasun Pharma | Bellamy J.A.,Shasun Pharma | Ball A.,Shasun Pharma | Ball A.,Syngenta | And 13 more authors.
Organic Process Research and Development | Year: 2012

A safe, practical and scalable process for manufacture of (-)-huperzine A has been developed and scaled up to manufacture several hundred grams of (-)-huperzine A with chemical and optical purity of >99%. The process consists of 11 chemical stages starting from commercially available materials with only nine isolation steps and no chromatography purification. This process provides a reliable and cost-effective source of synthetic (-)-huperzine A and its derivatives for pharmaceutical and nutraceutical markets. © 2012 American Chemical Society.


PubMed | Shasun Research Center
Type: Journal Article | Journal: Chemistry, an Asian journal | Year: 2012

The synthesis, photophysical, and electrochemical attributes of a novel class of boron difluorides containing an aromatic-fused alicyclic/hetero-alicyclic ring built on a -iminoenamine chromophoric backbone are reported. The compounds displayed large Stokes shifts (86-121nm), and were emissive in the solid state. The quantum yields obtained in solution at room temperature were unusually lower by an order of magnitude compared to those in the solid state. Some of the tested compounds displayed aggregation-induced emission (AIE). Single crystal XRD analyses revealed a lack of interplanar - interactions, which are presumed to be absent owing to non-planarity of the alicyclic component in the molecule. For most of the studied compounds, time-dependent DFT (TD-DFT) calculations invariably reveal intramolecular charge transfer (-*) characteristics with the frontier orbitals concentrated on the boron-nitrogen heterocycle. The participation of boron and fluorine atoms was found to be negligible.

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