Ishak Mat

Stability-indicating micellar electrokinetic chromatography method for the analysis of sumatriptan succinate in pharmaceutical formulations

A micellar electrokinetic chromatography method for the determination of sumatriptan succinate in pharmaceutical formulations was developed. The effects of several factors such as pH, surfactant and buffer concentration, applied voltage, capillary temperature, and injection time were investigated. Separation took about 5 min using phenobarbital as internal standard. The separation was carried out in reversed polarity mode at 20 °C, 26 kV and using hydrodynamic injection for 10s. Separation was achieved using a bare fused-silica capillary 50 μm×40 cm and background electrolyte of 25 mM sodium dihydrogen phosphate-adjusted with concentrated phosphoric acid to pH 2.2, containing 125 mM sodium dodecyl sulfate and detection was at 226 nm. The method was validated with respect to linearity, limits of detection and quantification, accuracy, precision and selectivity. The calibration curve was linear over the range of 100-2000 μg mL(-1). The relative standard deviations of intra-day and inter-day precision for migration time, peak area, corrected peak area, ratio of corrected peak area and ratio of peak area were less than 0.68, 3.48, 3.28, 2.97 and 2.83% and 2.01, 5.50, 4.46, 4.92 and 4.07%, respectively. The proposed method was successfully applied to the determinations of the analyte in tablet. Forced degradation studies were conducted by introducing a sample of sumatriptan succinate standard solution to different forced degradation conditions using neutral (water), basic (0.1 M NaOH), acidic (0.1 M HCl), oxidative (10% H(2)O(2)) and photolytic (exposure to UV light at 254 nm for 2 h). It is concluded that the stability-indicating method for sumatriptan succinate can be used for the analysis of the drug in various samples.

Study of TiO2 nanotubes as an implant application

Vertically aligned TiO2 nanotubes have become the primary candidates for implant materials that can provide direct control of cell behaviors. In this work, 65 nm inner diameters of TiO2 nanotubes were successfully prepared by anodization method. The interaction of bone marrow stromal cells (BMSC) in term of cell adhesion and cell morphology on bare titanium and TiO2 nanotubes is reported. Field emission scanning electron microscopy (FESEM) analysis proved interaction of BMSC on TiO2 nanotubes structure was better than flat titanium (Ti) surface. Also, significant cell adhesion on TiO2 nanotubes surface during in vitro study revealed that BMSC prone to attach on TiO2 nanotubes. From the result, it can be conclude that TiO2 nanotubes are biocompatible to biological environment and become a new generation for advanced implant materials.

Cellular Homeostasis and Antioxidant Response in Epithelial HT29 Cells on Titania Nanotube Arrays Surface

Cell growth and proliferative activities on titania nanotube arrays (TNA) have raised alerts on genotoxicity risk. Present toxicogenomic approach focused on epithelial HT29 cells with TNA surface. Fledgling cell-TNA interaction has triggered G0/G1 cell cycle arrests and initiates DNA damage surveillance checkpoint, which possibly indicated the cellular stress stimuli. A profound gene regulation was observed to be involved in cellular growth and survival signals such as p53 and AKT expressions. Interestingly, the activation of redox regulator pathways (antioxidant defense) was observed through the cascade interactions of GADD45, MYC, CHECK1, and ATR genes. These mechanisms furnish to protect DNA during cellular division from an oxidative challenge, set in motion with XRRC5 and RAD50 genes for DNA damage and repair activities. The cell fate decision on TNA-nanoenvironment has been reported to possibly regulate proliferative activities via expression of p27 and BCL2 tumor suppressor proteins, cogent with SKP2 and BCL2 oncogenic proteins suppression. Findings suggested that epithelial HT29 cells on the surface of TNA may have a positive regulation via cell-homeostasis mechanisms: a careful circadian orchestration between cell proliferation, survival, and death. This nanomolecular knowledge could be beneficial for advanced medical applications such as in nanomedicine and nanotherapeutics.

Crystal Structure of TiO 2 Nanotube Arrays Anodized at Different Voltage for Cell-Metal Interaction

In recent study, vertically aligned TiO2 nanotubes have become the primary candidates that can provide direct control of many type cell behaviors and its functionality. TiO2 nanotubes were successfully developed within 10 V to 40 V of applied potential. The intensity of peaks (101) increases with increasing voltage up to 40 V, indicating an improvement in degree of crystalinity. The average crystallite size of the samples anodized at 10 V is about 19.65 nm and increase to 30.88 nm at 40 V. PA6 cell interaction were high on 40 V sample (110 nm-diameter) TiO2 nanotubes . It was found that anatase phase with appropriate diameter are believed to affect the growth of cells.

TiO2 Foam: Characterization and Cell Adhesion

In recent years, it has been proposed that the new era of implants design should be focused on the use of the new generation of biocompatible materials or reengineers the currently available materials. The objective of this research was to study cell-metal interactions using highly porous TiO2 foam. To obtain the porous TiO2 foam, polymeric foam replication methods might be one of the most effective methods. Surface chemical composition, morphology and phase are investigated by field emission scanning electron microscope (FESEM) and X-Ray Diffraction (XRD). In vitro cellular response of cells has been studied on TiO2 foam. In the investigations of the cellular responses of cells, two aspects were considered: the number of growing cells and their morphological features. It was clear that rough surface morphology was important factor for better cell-metal interaction. Surface topography can affect the cell migratory significantly and adhesion behavior on implant surfaces.

Effect of processing condition on the formation of ZnSe nanoparticles

ZnSe nanoparticles were synthesised by wet chemical route. The effect of refluxing time was studied extensively on the formation of ZnSe nanoparticles via a rapid polyol approach. It was found that a rapid polyol approach is able to produce ZnSe microspheres which are composed of numerous small sizes of nanoparticles. Moreover, longer refluxing time gave monodispersed and better uniformity of ZnSe nanostructures but also bigger size of microspheres.