ANALYTICAL METHOD DEVELOPMENT AND VALIDATION STUDIES OF TICAGRELOR TABLETS BY RP-HPLC

Objective: The present study was conducted to develop a simple and precise analytical method for the estimation of ticagrelor in tablet formulation.Methods: Reverse Phase HPLC was used for method development and validation studies of ticagrelor. The optimum chromatographic conditions comprised of C18 column (Kromasil, 250×4.6 mm, 5 µ) as the stationary phase and aqueous buffer (containing 0.5 ml formic acid and triethylamine each in water) and acetonitrile in the ratio of 50:50 v/v as the mobile phase. The flow rate was 1.3 ml/min with detection at 256 nm and a run time of 6 min. Forced degradation studies were conducted and the isocratic mode was modified to a gradient mode to make the method stability indicating in nature.Results: The retention time of ticagrelor was 3.372 min. The linearity studies indicated that the range of the developed method was 20-90 ppm with a correlation coefficient of 0.9956. The method was specific with a percent mean recovery was found to be 99.93%.. The % RSD in the precision studies was 0.069. The validated method was applied to conduct the assay of ticagrelor in tablets and the with a percent mean recovery of 99.82%. The modified method was capable of resolving 13 related substances from the ticagrelor peak in the forced degradation studies.Conclusion: The developed and validated RP-HPLC isocratic method was simple, accurate and precise as per the ICH guidelines. It was suitable for the analysis of ticagrelor in bulk and tablet formulation. The modified gradient method can be used to resolve the in-process impurities and related substances and can be directly applied to liquid chromatography hyphenated with mass spectroscopy (LC/MS) studies with minor modifications for identification of related substances

Meglumine catalyzed one-pot green synthesis of novel 4,7-dihydro-1H-pyrazolo3,4-bpyridin-6-amines

Meglumine efficiently catalyzes the one-pot, five-component reaction of hydrazine, ethyl acetoacetate, aryl aldehydes, substituted phenylacetonitriles and ammonium acetate in ethanol at room temperature to afford novel 4,7-dihydro-1H-pyrazolo3,4-bpyridin-6-amine derivatives. The present approach offers several advantages such as shorter reaction durations, low cost, excellent yields, milder reaction conditions, simple workup procedure and is environment friendly. All the synthesized derivatives are characterized by IR,1H NMR,13C NMR, HRMS and CHN analysis. � 2016 Mohamed Afzal Pash

Thermal slip in oblique radiative nano-polymer gel transport with temperature-dependent viscosity : solar collector nanomaterial coating manufacturing simulation

Nano-polymeric solar paints and sol-gels have emerged as a major new development in solar cell/collector coatings offering significant improvements in durability, anti-corrosion and thermal efficiency. They also exhibit substantial viscosity variation with temperature which can be exploited in solar collector designs. Modern manufacturing processes for such nano-rheological materials frequently employ stagnation flow dynamics under high temperature which invokes radiative heat transfer. Motivated by elaborating in further detail the nanoscale heat, mass and momentum characteristics, the present article presents a mathematical and computational study of the steady, two-dimensional, non-aligned thermo-fluid boundary layer transport of copper metal-doped water-based nano-polymeric sol gels under radiative heat flux. To simulate real nano-polymer boundary interface dynamics, thermal slip is analysed at the wall. A temperature-dependent viscosity is also considered. The conservation equations for mass, normal and tangential momentum and energy are normalized via appropriate transformations to generate a multi-degree, ordinary differential, non-linear, coupled boundary value problem. Numerical solutions are obtained via the stable, efficient Runge-Kutta-Fehlberg scheme with shooting quadrature in MATLAB symbolic software. Validation of solutions is achieved with a Variational Iterative Method (VIM) utilizing Langrangian multipliers. The impact of key emerging dimensionless parameters i.e. obliqueness parameter, radiation-conduction Rosseland number (Rd), thermal slip parameter (ALPHA), viscosity parameter (m), nanoparticles volume fraction (PHI) on non-dimensional normal and tangential velocity components, temperature, wall shear stress, local heat flux and streamline distributions is visualized graphically. Shear stress and temperature are boosted with increasing radiative effect whereas local heat flux is reduced. Increasing wall thermal slip parameter depletes temperatures

Bilateral systematised epidermolytic epidermal nevus: A case report

Verrucous epidermal nevi (VEN) are benign congenital hamartomas consisting of keratinocytes. Histological examination mostly exhibits hyperkeratosis, acanthosis, papillomatosis and, rarely, the features of epidermolytic hyperkeratosis (EHK). We report a case of a 6-year-old boy who presented at Aga Khan University Hospital, Karachi, Pakistan with bilaterally symmetrical linear epidermal nevi following Blaschko\u27s lines and showing epidermolytic hyperkeratosis on histology. The patient was treated with topical keratolytics and emolients which led to considerable improvement. To the best of the authors\u27 knowledge, this is the first report of VEN from Pakistan

SELINDA: a secure, scalable and light-weight data collection protocol for smart grids

Security in the smart grid is a challenge as an increasing number of sensors and measurement devices are connected to the power grid. General purpose security protocols are not suitable for providing data security to devices with limited memory, computational power and network connectivity. In this paper, we develop a secure and light-weight scalable security protocol that allows a power system operator (PO) to collect data from measurement devices (MDs) using data collectors (DCs). The security protocol trades off between computations and device memory requirements and provides flexible association between DC and MDs. These features allow data to be securely transferred from MDs to PO via mobile or untrustworthy DCs. We analyze the complexity and security of the protocol and validate its performance using experiments. Our results confirm that our proposed protocol collects data in a secure, fast and efficient manner. © 2013 IEEE.published_or_final_versio

Comparative node selection-based localization technique for wireless sensor networks: A bilateration approach

Wireless sensor networks find extensive applications, such as environmental and smart city monitoring, structural health, and target location. To be useful, most sensor data must be localized. We propose a node localization technique based on bilateration comparison (BACL) for dense networks, which considers two reference nodes to determine the unknown position of a third node. The mirror positions resulted from bilateration are resolved by comparing their coordinates with the coordinates of the reference nodes. Additionally, we use network clustering to further refine the location of the nodes. We show that BACL has several advantages over Energy Aware Co-operative Localization (EACL) and Underwater Recursive Position Estimation (URPE): (1) BACL uses bilateration (needs only two reference nodes) instead of trilateration (that needs three reference nodes), (2) BACL needs reference (anchor) nodes only on the field periphery, and (3) BACL needs substantially less communication and computation. Through simulation, we show that BACL localization accuracy, as root mean square error, improves by 53% that of URPE and by 40% that of EACL. We also explore the BACL localization error when the anchor nodes are placed on one or multiple sides of a rectangular field, as a trade-off between localization accuracy and network deployment effort. Best accuracy is achieved using anchors on all field sides, but we show that localization refinement using node clustering and anchor nodes only on one side of the field has comparable localization accuracy with anchor nodes on two sides but without clustering

Historical perspective of in situ hybridization for the analysis of genomic constitution of plants

In situ hybridization involves hybridization of DNA or RNA probes to the cytological preparations. The technique originally used auto-radiographic labeling to map both repetitive and low copy DNA sequences. The problem associated with this technique was its short half life, lack of safety and long exposure time which hindered its widespread use in DNA hybridization. To overcome these problems, non isotopic in situ hybridization was developed for use in animal and plant species. In the last decade, the development of haptens and fluorochromes enabled simultaneous multicolored detection of differentially labeled probes. Characterization of parental genomes in interspecific hybrids, restructured chromosomes, gene mapping, detecting nature of chromosome pairing, establishing phylogenetic relationship among the species and localizing introgressed segment have been successfully achieved by fluorescence in situ hybridization. Keywords: In situ hybridization, phylogenetic relationship, homoeologous pairin

Isolation of 4,5- O

There is a continual need to develop novel and effective melanogenesis inhibitors for the prevention of hyperpigmentation disorders. The plant Artemisia capillaris Thunberg (Oriental Wormwood) was screened for antipigmentation activity using murine cultured cells (B16-F10 malignant melanocytes). Activity-based fractionation using HPLC and NMR analyses identified the compound 4,5-O-dicaffeoylquinic acid as an active component in this plant. 4,5-O-Dicaffeoylquinic acid significantly reduced melanin synthesis and tyrosinase activity in a dose-dependent manner in the melanocytes. In addition, 4,5-O-dicaffeoylquinic acid treatment reduced the expression of tyrosinase-related protein-1. Significantly, we could validate the antipigmentation activity of this compound in vivo, using a zebrafish model. Moreover, 4,5-O-dicaffeoylquinic acid did not show toxicity in this animal model. Our discovery of 4,5-O-dicaffeoylquinic acid as an inhibitor of pigmentation that is active in vivo shows that this compound can be developed as an active component for formulations to treat pigmentation disorders