Authors:Susheel Varghese, P. Vasanthi, and Thengungal Ravi
This paper describes a validated high-performance thin-layer chromatography (HPTLC) method for the simultaneous determination of ivermectin (IVM) and albendazole (ALB) in combined tablet dosage forms. The HPTLC separation was carried out on aluminum-backed silica gel 60 F254 layers using toluene-ethyl acetateglacial acetic acid, 6:4:0.5 (ν/ν/ν), as the mobile phase. Quantification was achieved with UV detection at 247 nm. The developed analytical method was validated according to International Conference on Harmonization guidelines in terms of parameters such as accuracy, precision, linearity, and specificity. Good linearity was observed in the concentrations ranging from 0.12 to 0.54 and 8 to 36 μg per band for IVM and ALB, respectively. The recovery study results ranged from 98% to 101% for IVM and ALB, showing the accuracy of the method. The method was successfully applied for the analysis of the drugs in laboratory-prepared mixtures and commercial tablets. The developed method is simple, precise, and sensitive, and applicable for the simultaneous determination of IVM and ALB in pure powder and tablets.
A rapid and sensitive reverse-phase liquid chromatographic method using ultraviolet detector was developed and validated for estimation of raloxifene hydrochloride in rabbit plasma. Plasma samples were extracted using simple protein precipitation-extraction method. The method was developed under isocratic conditions using a Zorbax SB-C8 analytical column with optimum mobile phase composition of 20 mM pH-4.5 ammonium acetate buffer-acetonitrile (63:37 υ/υ) at a flow rate of 1 mL min−1. The detector response was found to be linear in the concentration range of 50–1500 ng mL−1. High recoveries ranging from 97.2% to 100.2% were obtained, which precludes the use of internal standard. The developed method was found to be accurate, precise, and selective in the estimation of raloxifene hydrochloride in rabbit plasma based on the results of method validation carried out as per standard guidelines. The drug was found to be stable under various processing and storage conditions. The developed method was successfully applied in the estimation of raloxifene hydrochloride and the determination of various pharmacokinetic parameters post-intravenous bolus administration of drug in rabbits.
The effects of variation in different parameters on the environmental distribution of base line 137Cs and 40K activities in Kaiga environment and their migration into biosphere are discussed. Transfer factors of these radionuclides from soil to different parts of commonly available plants in this region were estimated. Base line radioactivity levels in soil at Kaiga were higher as compared to pre-operational values reported from other power station sites in India and were mainly attributed to the very high precipitation rate prevailing in this area. Also, this area being an undisturbed forest land, fallout activities are re-circulated to the soil by the decay of parts of trees.40K and 137Cs activity levels in leaves of shallow rooted plants were found to be higher as compared to that in deep rooted trees. Transfer factors of soil to plant parts revealed that there is no major bio-accumulation of 137Cs in any parts of Colocassia esculenta (L.) and Chromolaena odorata (L.) King & Robinson. Comparison of 40K/137Cs ratio between soil and different parts of these plants has revealed that uptake of K is relatively more efficient as compared to that of Cs, presumably because of the faster kinetics of K due to its larger atom inventory in the soil.
Two modifications of the existing method of determining free acidity in highly concentrated uranyl nitrate solutions by alkalimetric
titrations in neutral potassium oxalate medium have been carried out to improve the reliability of the method. Free acidities
of several synthetic solutions containing uranium and nitric acid in a wide range of concentration ratios were determined
by all the three methods and compared with the results obtained by a more accurate ion exchange method. Interference from
other hydrolyzable ions and the precision and accuracy were studied and compared.
The species of radioiodine in the primary coolant water of the heavy water moderated, heavy water cooled 100 MW research reactor have been identified. It was observed that IO
was the major species in the reactor coolant during reactor operation and I– was the major species during shutdown. Organic and elemental forms amount only to less than 2% of total radioiodine. A simple method was developed for the estimation of gross iodine activity in reactor coolant water. The method involves the separation of all inorganic forms of iodine into a photographic film consisting of a thin layer of silver halide. The iodine in the film was estimated by gross counting of the film in a Geiger-Müller counter. Gross iodine activity in the reactor coolant samples estimated by the present method were in agreement with that obtained by direct -spectrometry with a Ge detector. It is concluded that the method can be used for the routine estimation of radioiodine in reactor coolant water.133I/131I and135I/131I ratios in the film were estimated and found to be useful in identifying split rod conditions in the reactor.
129I content of batches of Na131I vials, used for nuclear medicine procedures, was estimated by neutron activation analysis. The average value of the129I/131I activity ratio /corresponding to zero decay time of the latter/ was /4.98±2.8/x10–9. It is concluded that the contribution of129I from medical applications of131I in India is insignificant in relation to that from nuclear fuel cycle activities.
Authors:P. Ravi, R. Vats, S. Joseph, and N. Gadekar
A simple, sensitive and rapid high-performance liquid chromatography method with ultraviolet (UV) detector was developed and validated for the analysis of Nebivolol (NBL) in rat plasma. The plasma sample, spiked with raloxifene hydrochloride as an internal standard (IS), was subjected to single step protein precipitation method prior to analysis. Chromatographic separation was achieved on the Agilent C8 (150 mm × 4.6 mm, 5 μm) column and monitored at a wavelength of 280 nm. Elution was carried out, in an isocratic mode, using a mobile phase consisting of acetonitrile and potassium di-hydrogen orthophosphate buffer (pH 3.5 ± 0.1) in the ratio of 37:63 v/v. Retention times of IS and NBL were 5.1 ± 0.10 min and 8.01 ± 0.12 min, respectively. No interference was observed from plasma components in the analysis of NBL and IS. Calibration curve was linear over the range of 125–3000 ng/mL (r2 = 0.999). NBL was found to be stable under various processing and storage conditions. The developed method was applied in the quantification of NBL in plasma samples, determining various pharmacokinetic parameters from intravenous bolus and oral administration of the drug in Wistar rats. NBL was found to follow two compartmental open models in Wistar rats.
Authors:S. Sugandhi, S. Prabhu, D. Mishra, P. Ravi, and A. Hegde
Mumbai Harbour Bay (MHB) is a recipient of low level treated effluents from BARC, Trombay. In addition, the Bay is also a
recipient of domestic and industrial wastes from the city of Mumbai and adjoining areas. The average value of uranium concentration
reported for Indian Bay water at Tarapur and Mumbai is ~3.0 ppb which is comparable with the reported value for Arabian sea.
As such the global average is reported to be ~3.3 ppb by Oceanologists. The present study deals with the distribution of uranium
in seawater of MHB. The uranium activity in MHB by alpha spectrometry was found to be between 1.0 and 4.4 ppb with an average
concentration of 2.5 ppb which is comparable with the earlier reported average activity of 2.6 ppb in the MHB as well as those
reported globally. To compare the results obtained by alpha spectrometry, uranium estimation was also carried out using Laser
fluorimeter and the levels of uranium concentration have ranged between 0.8 and 4.9 ppb with an average concentration of 2.7 ppb.
Authors:P. Ravi, M. Iyer, S. Sahasrabudhe, M. Subramanian, and S. Somasundaram
Methods have been developed for the routine analysis of129I in effluents of fuel reprocessing plants using 29.4 keV xenon X-rays. Direct counting methods have been standardized in liquid medium as well as in ion-exchange resin medium. A low energy photon spectrometry Ge detector system and a well-type NaI/Tl/ detector are used for direct counting. Attenuation of xenon X-rays in liquid medium as well as in ion-exchange resin medium have been studied. Sample size is optimized by studying the self attenuation of xenon X-rays in the sample. Activity as low as 1 Bq could be detected with an accuracy of 11% and 30% using LEPS and NaI/Tl/counting systems, respectively.
Authors:S. Ravi, S. Ravi, A. K. Deepa, A. K. Deepa, S. Susheela, S. Susheela, P. V. Achuthan, P. V. Achuthan, S. Anil Kumar, and U. Jambunathan
A method has been developed for the estimation of 90Sr in reprocessed uranium oxide samples obtained from the Purex processing of natural uranium spent fuel discharged from the
research reactor. The method employs a combination of precipitation and solvent extraction procedure to eliminate other beta-impurities
prior to resorting to the estimation of 90Sr by beta-counting. 106Ru was eliminated by volatalizing with perchloric acid, uranium was removed by carrier precipitation with strontium as sulphate.
The sulphate precipitate was converted to carbonate and dissolved in nitric acid. 234Th and 234Pa were eliminated by synergistic solvent extraction using tri-n-butyl phosphate and thenoyl trifluoroacetone extractant mixture
in xylene. An iron scavenging step was included to remove any residual impurities. Finally, strontium is precipitated as SrC2O4. H2O. The separated 90Sr activity was followed to check the equilibrium growth of 90Y.