http://nopr.niscair.res.in/handle/123456789/9051 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/9061 Title: Synthesis, characterization and physical properties studies of an anionic surfactant <br/> <br/>Authors: Verma, Anupam; Purkait, Mihir Kumar <br/> <br/>Abstract: An anionic surfactant, sodium octadecyl sulfate was synthesized from non-toxic <i style="">n</i>-octadecanol using chlorosulfonic acid as the sulfating agent. The synthesized surfactant was characterized by melting point, FT-IR, ¹H-NMR and ESI-Mass spectroscopic studies. Physical properties of the surfactant like Krafft point, surface tension, conductivity, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and powder X-ray diffraction (XRD) have also been studied. The surface tension and critical micelle concentration (CMC) were found to be around 48 mN/m and 0.2 mM at 30°C, respectively. Both CMC and surface tension value decreased with increase in temperature. CMC decreased from 0.2 to 0.1 mM when temperature increased from 30 to 50^oC. The Krafft point is 56°C and the melting point is 209^oC. <br/> <br/>Page(s): 233-237 http://nopr.niscair.res.in/handle/123456789/9060 Title: Simultaneous spectrophotometric estimation and validation of three component tablet formulation containing paracetamol, nimesulide and tizanidine <br/> <br/>Authors: Chandratrey, A; Sharma, R <br/> <br/>Abstract: In the present study, two spectrophotometric methods that do not require prior separation for simultaneous estimation of three drugs: paracetamol, nimesulide, and tizanidine in tablet formulation have been reported. Shimadzu UV-1700, capable of multi-component analysis was used for quantitation. Method I was based on derivative spectrophotometry and the absorbances were measured at 229.5, 271, and 323.0 nm, being the zero crossing points for paracetamol, nimesulide and tizanidine, respectively. Method II is based on multi-wavelength spectroscopic method, absorbances of standard solutions were measured at 229.0 nm, 272.0 nm, 262.0 nm and 323.0 nm based on statistical calculations and results of the sample solutions. All the three drugs obey Beer’s law in the concentration range employed for the methods. The results of the analysis for both methods were tested and validated for various parameters according to International Conference on Harmonization Q 2B guidelines. The utility of the developed methods has been demonstrated by analysis of commercially available tablet dosage form. <br/> <br/>Page(s): 229-232 http://nopr.niscair.res.in/handle/123456789/9059 Title: Micro and nanogram determination of lamotrigine in pharmaceuticals by visible spectrophotometry using bromophenol blue <br/> <br/>Authors: Rajendraprasad, N; Basavaiah, K; Vinay, K B <br/> <br/>Abstract: Three reliable, rapid, highly sensitive and selective methods have been developed and validated for the determination of lamotrigine (LMT) in pure drug and in tablets. The first method (method A) is based on the formation of chloroform extractable ion-pair complex between LMT and bromophenol blue (BPB) at pH 1.44±0.01 with a wavelength of maximum absorption at 420 nm. In the second (method B) and third (method C) methods, the drug-dye ion pair is dissolved in either ethanolic H₂SO₄ and resulting acid form of the dye is measured at 420 nm or ethanolic KOH and the resulting base form of the dye is measured at 600 nm. All variables affecting the drug-dye complex formation and its extraction into CHCl₃ have been investigated and conditions optimized. Beer’s law was obeyed over 2.5-25 µg mL^-1, 50-400 ng mL^-1 and 10-80 ng mL^-1, for method A, method B and method C, respectively. The calculated molar absorptivity values are 7.26 <img src='/image/spc_char/cross.gif' border=0> 10³, 5.4 <img src='/image/spc_char/cross.gif' border=0>10⁵ and 2.6 <img src='/image/spc_char/cross.gif' border=0> 10⁶ l mol^-1 cm^-1, respectively, for methods A, B and C; and the corresponding Sandell sensitivities are 0.0353, 0.0005 and 0.0001 µg cm^-2. The limits of detection (LOD) and quantification (LOQ) have also been reported. The stoichiometry of the formed ion-pair complex was found to be 1:1.for method A, and the stability constant is also calculated. The accuracy and precision of the methods were evaluated on intra-day and inter-day basis; and the relative error (RE) and the relative standard deviation (RSD) were ≤ 2.0% and ≤ 1.4%, respectively. The proposed methods were successfully applied for the determination of LMT in bulk powder and in tablets. <br/> <br/>Page(s): 220-228 http://nopr.niscair.res.in/handle/123456789/9058 Title: Synthesis, characterization and bioactivity of Fipronil derivatives as a lead for new insecticide <br/> <br/>Authors: Xiaohua, Zheng; Dingxin, Jiang; Zhicheng, Liu; Hanhong, Xu <br/> <br/>Abstract: Fipronil is the first phenylpyrazole insecticide introduced for pest control. In order to further study fipronil derivatives of better bioactivity and systemic property derived from the pyrazole-5-amine by addition reaction/elimination/substitution reaction,<span style="color: rgb(204, 0, 51);"> ten modified compounds were prepared. Their insecticidal bioactivities against the 3^rd instar larvae of <i>Plutella xylostella</i> were determined. The data suggested that bioactivities of most of the compounds are higher than that of fipronil, while some of them showed only modest activity as compared with fipronil. <i style=""></i> </span> <br/> <br/>Page(s): 215-219