Modification of WS2thin film properties using high dose gamma irradiation.

The tunability of the transition metal dichalcogenide properties has gained attention from numerous researchers due to their wide application in various fields including quantum technology. In the present work, WS2has been deposited on fluorine doped tin oxide substrate and its properties have been studied systematically. These samples were irradiated using gamma radiation for various doses, and the effect on structural, morphological, optical and electrical properties has been reported. The crystallinity of the material is observed to be decreased, and the results are well supported by x-ray diffraction, Raman spectroscopy techniques. The increase in grain boundaries has been supported by the agglomeration observed in the scanning electron microscopy micrographs. The XPS results of WS2after gamma irradiation show evolution of oxygen, carbon, C=O, W-O and SO4-2peaks, confirming the addition of impurities and formation of point defect. The gamma irradiation creates point defects, and their density increases considerably with increasing gamma dosage. These defects crucially altered the structural, optical and electrical properties of the material. The reduction in the optical band gap with increased gamma irradiation is evident from the absorption spectra and respective Tauc plots. TheI-Vgraphs show a 1000-fold increase in the saturation current after 100 kGy gamma irradiation dose. This work has explored the gamma irradiation effect on the WS2and suggests substantial modification in the material and enhancement in electrical properties.

Development of Solid-Phase Extraction and HPLC Method for Simultaneous Estimation of Ilaprazole and Glimepiride in Rat Plasma: Application to Pharmacokinetic Studies.

A novel, simple and mass spectrometry (MS) compatible high-performance liquid chromatography (HPLC) method is reported for the simultaneous estimation of ilaprazole (ILA) and glimepiride (GLM) in rat plasma. The bio-analytical procedure involves extraction of ILA, GLM and internal standard (IS) from rat plasma with a solid-phase extraction (SPE) process. The chromatographic analysis was performed on Waters-600 system using an isocratic mobile phase comprising methanol:water (80:20 % v/v) with pH of water modified to three using formic acid at a flow rate of 1.0 mL/min and Kinetex C18 column maintained at 30 ± 1°C. The signals were monitored using a PDA detector set at 225 nm. IS, ILA and GLM eluted at 2.04, 4.7 and 7.4 min, respectively, and the total run time was 10 min. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 10-600 ng/mL (r2 = 0.999). The intra- and inter-day precisions for ILA and GLM were (%RSD values) in the range of 1.52-9.74 and 1.52-11.76%, respectively, in rat plasma. The method was successfully applied in pharmacokinetic studies followed by oral administration of GLM and ILA in rats.

Study of stress degradation behavior of rasagiline mesylate under hydrolytic conditions by high performance liquid chromatography.

A precise and rapid reverse phase HPLC method has been developed for the estimation of Rasagiline Mesylate in bulk drug under stressed hydrolytic conditions according to ICH guidelines Q1(A)R2. The stressed samples of Rasagiline Mesylate were analyzed using Prontosil ODS column. The mobile phase consists of methanol and Phosphate buffer. The pH of the phosphate buffer was adjusted to 3.0 using orthophosphoric acid. The composition of mobile phase Methanol: Phosphate buffer (75:25 v/v) was kept constant up to 1 minute and then changed to 90:10 v/v in next 9 min by HPLC gradient programming. The flow rate was maintained at 1.0 ml/min and detection was carried out at 210 nm using 996 PDA detector. The method was validated in terms of linearity, accuracy, precision specificity and selectivity. The method was found to be linear in the range of 5-15 µg/ml with a correlation coefficient of 0.993.

Gradient HPLC-DAD determination of paracetamol, phenylephrine hydrochloride, cetirizine in tablet formulation.

Present work describes the development and validation of a simple and reliable high-performance liquid chromatography-diode array detection (HPLC-DAD) procedure for the analysis of phenylephrine hydrochloride (PHE), paracetamol (PAR) and cetirizine dihydrochloride (CET), in pharmaceutical mixture. The method was applied successfully on tablet dosage form. Effective chromatographic separation of PHE, PAR and CET was achieved using a Kinetex-C18 (4.6, 150 mm, 5 mm) column with gradient elution of the mobile phase composed of 10 mM phosphate buffer (pH 3.3) and acetonitrile. The elution was a 3 step gradient elution program step-1 started initially with 2% (by volume) acetonitrile and 98% phosphate buffer (pH 3.3) for first 2 min. In step-2 acetonitrile concentration changed linearly to 20% upto 12 min the analysis was concluded by step-3 changing acetonitrile to 2% upto 20 min. The reliability and analytical performance of the proposed HPLC procedure were statistically validated with respect to linearity, ranges, precision, accuracy, selectivity and robustness. Calibration curves were linear in the ranges 5-15, 250-750 and 2.5-7.5 µg/ml for PHE, PAR and CET, with correlation coefficients >0.9996. The validated HPLC method was applied to a pharmaceutical mixture of a marketed preparation tablet in which the analytes were successfully quantified with good recovery values with no interfering peaks from the excipents.

Development and validation of RP-HPLC method for sildenafil citrate in rat plasma-application to pharmacokinetic studies.

Sildenafil citrate (SIL) is used in the treatment of erectile dysfunction and other chronic disorders. For the pharmacokinetic investigation of SIL we developed a simple and sensitive method for the estimation of SIL in rat plasma by reverse phase high-performance liquid chromatography (RP-HPLC). The drug samples were extracted by liquid-liquid extraction with 300 µl of acetonitrile and 5 ml of diethyl ether. Chromatographic separation was achieved on C18 column using methanol:water (85:15 v/v) as mobile phase at a flow rate of 1 ml/min and UV detection at 230 nm. The retention time of SIL was found to be 4.0 min having a separation time less than 5 min. The developed method was validated for accuracy, precision, linearity and recovery. Linearity studies were found to be acceptable over the range of 0.1-6 µg/ml. The method was successfully applied for the analysis of rat plasma sample for the application in pharmacokinetic study, drug interaction, bioavailability and bioequivalence.

Development and validation of RP-HPLC method for simultaneous estimation of glimepiride and sildenafil citrate in rat plasma-application to pharmacokinetic studies.

A simple and sensitive method was developed for simultaneous estimation of Glimepiride (GLIM) and Sildenafil citrate (SIL) in rat Plasma by reverse phase high performance liquid chromatography (RP-HPLC). The drug samples were extracted by liquid-liquid extraction with 300 µl of acetonitrile and 5 ml of diethyl ether. Chromatographic separation was achieved on C18 column using methanol: water (85:15 v/v) as mobile phase at a flow rate of 1 ml/min and UV detection at 230 nm. The retention time of GLIM and SIL was found to be 2.5 and 4.0 min respectively with total run time of 7 min. The developed method was validated for accuracy, precision, linearity and recovery. The method was linear and found to be acceptable over the range of 100-12 000 ng/ml. The method was successfully applied for the analysis of rat plasma sample for application to pharmacokinetic.

Assessment of use of complementary alternative medicine and its impact on quality of life in the patients attending rheumatology clinic, in a tertiary care centre in India.

PURPOSE: Complementary and alternative medicine (CAM) has witnessed an increase in use in recent times in rheumatological conditions and is expected to have impact on the quality of life (QOL). We had planned to conduct this study to investigate the extent of use of CAM and its effect on QOL of patients at a tertiary care center. MATERIALS AND METHODS: Ethics committee approval was obtained. Sixty patients suffering from osteoarthritis (OA) and rheumatoid arthritis (RA) were enrolled as per the selection criteria, after obtaining their informed consent. Each patient was interviewed for CAM use/non-use, and Western Ontario and McMaster Universities (WOMAC) (modified) index for QOL was recorded by the study personnel. STATISTICAL ANALYSIS: The normality was checked by using Kolmogorov-Smirnov test. Descriptive statistics was performed and Mann-Whitney U-test was used to compare the QOL of CAM users and non-users. RESULTS: Of the 60 patients enrolled with OA (10) and RA (50), 58% (35/60) used CAM. Ayurveda and massage therapy were the commonest [80% (28/35)], followed by yoga asana [34% (12/35)] and homoeopathy [20% (7/35)]. It was observed that combinations of therapies were used too. Nearly half [49% (17/35)] of the CAM users were on self-prescribed medication and 71% (25/35) of them did not inform the physician of CAM use. The QOL of CAM users (WOMAC score: 56.31 ± 6.82) was better than that of CAM non-users (WOMAC score: 60.16 ± 4.02) (P value 0.01). CONCLUSION: Patients with RA frequently used CAM and QOL improvised with CAM use. We observed that self-administration of CAM was common and this was not informed to the treating physician.

Condensation-induced jumping water drops.

Water droplets can jump during vapor condensation on solid benzene near its melting point. This phenomenon, which can be viewed as a kind of micro scale steam engine, is studied experimentally and numerically. The latent heat of condensation transferred at the drop three phase contact line melts the substrate during a time proportional to R (the drop radius). The wetting conditions change and a spontaneous jump of the drop results in random direction over length approximately 1.5R , a phenomenon that increases the coalescence events and accelerates the growth. Once properly rescaled by the jump length scale, the growth dynamics is, however, similar to that on a solid surface.