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  • Author or Editor: N. Desai x
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Abstract  

A solvent extraction method is proposed for the extraction and separation of uranium from salicylate media using tris-/2-ethyl hexyl/ phosphate dissolved in xylene as an extractant. The optimum conditions were evaluated from a critical study of pH, salicylate concentration, extractant concentration, period of equilibration and diluent. The method permits the separation of uranium from thorium, cerium, titanium, zirconium, hafnium, copper, vanadium and chromium from binary mixtures and is applicable to the analysis of uranium in synthetic samples. The method is precise, accurate, fast and selective.

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Summary

Stability-indicating HPLC method was developed for determination of solifenacin succinate (SLN) as bulk drug and from pharmaceutical formulation. The HPLC separation of SLN from its degradation products was achieved using Oyster BDS C8 (250 mm × 4.6 mm i.d., 5 μm particle size) column with a flow rate 0.7 mL min−1 and using a UV detector to monitor the eluate at 210 nm. The mobile phase was composed of 10 mM ammonium formate buffer (adjusted pH 3 with formic acid)-acetonitrile-methanol (52.5:37.5:10, v/v/v). The linear regression analysis data for the calibration plots showed good linear relationship with r 2 = 0.9999 in the working concentration range of 2–100 μg mL−1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.07 and 0.21 μg mL−1, respectively. API and formulation of SLN were subjected to acid and alkali hydrolysis, oxidation, thermal and photodegradation. Standard drug peak was well resolved from the peaks of degradation products with significantly different retention time values. Also, isolation and identification of major base degradation product were carried out. The method is simple, accurate, specific, repeatable, stability-indicating, reduces the duration of the analysis and is suitable for routine determination of SLN in pharmaceutical formulation.

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Abstract  

A single reagent radioimmunoassay for thyroxine in blood samples absorbed on filter paper for the mass screening of neonatal hypothyroidism is described. Blood samples were collected by pricking the heel of newborn babies (3 days old) and pressing Whatman 3 filter paper against the wound. 6 mm diameter blood spots were punched out at the time of assay and incubated with 0.4 ml of a preincubated antigen-antibody complex for six hours at 37 °C. 1 ml of 22% polyethylene glycol is used for the precipitation of antigen-antibody complex. The assay has a sensitivity of 2.2 ng/ml. 500 samples collected from newborns were analyzed in the assay and gave a mean of 117.6±31.9 ng/ml.

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Abstract  

A simple and reliable technique for the simultaneous estimation of serum triiodothyronine (T3) and thyroxine (T4) is discussed. T3 assay was done by the solid phase technique using antibody coated Eppendorf pipette tips. T4 assay was done by the polyethylene glycol separation system. The assay used 50 l of serum sample. Inter-assay and intra-assay coefficient of variation are less than 12% throughout the assay range, for both assays.

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Hydroxycitric acid made the genus Garcinia economically important. Genetic and chemical diversity has been studied in Garcinia species using molecular markers, HCA and antioxidant activity. Nine species were collected and screened for molecular diversity and six were subjected to analyse antioxidant and HCA content and its interspecies variability. A total of 129, 125 and 89 bands with polymorphism of 78.74%, 78.4% and 93.36% were obtained using ISSR, RAPD and EST-SSR, respectively. The average PIC value obtained with ISSR, RAPD and EST-SSR markers was 0.9161, 0.9440 and 0.8903, respectively. Determined HCA content by HILIC-HPLC system using 0.1% orthophosphoric acid and acetonitrile (30:70) as mobile phase in fruit powder of various Garcinia species was found to be significantly different. G. gummi-gutta, G. indica and G. xanthochymus are rich of HCA containing 12.44±1.04%, 7.92±0.83% and 6.3±0.286%, respectively. G. morella, G. talbotii and G. celebica contained very negligible amount of HCA, 0.023±0.012%, 0.083±0.034% and 0.34±0.013%, correspondingly. G. talbotii showed high antioxidant capacity (95.40±0.720). Below that G. indica and G. xanthochymus were showing significant amount of total phenols (1.23±0.015 and 1.07±0.008), flavonoids (11.17±0.075 and 12.35±0.219) and antioxidant activity (90.73±0.976 and 91.37±0.854). Correlation analysis found significant association between molecular and chemical variation indicating influence of genetic background on the observed HCA and antioxidant profiles. The conducted analysis showed the most distinct species at the genetic and chemical levels were G. gummi-gutta, G. indica and G. xanthochymus. This study signifies the utility of molecular and chemical fingerprints for commercial exploitation of HCA from Garcinia species.

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