Investigation of charge dynamics in the corona-aged silicone rubber alumina nanocomposite

The effect of corona aging on the surface potential dynamics and charge trap characteristics of silicone rubber alumina nanocomposite are examined using surface potential decay measurement. The aging was carried out by exposing the specimens to corona stress generated by a high-frequency AC multi needle-plane electrode system. The results show that the addition of alumina filler increases the surface potential decay time and maximum trap energy. A reduction in trap depth is observed with the corona aging, and the addition of alumina filler limits the degradation and change in charge trap distribution. The results of an analysis of the space charge behavior of different nanocomposites and their comparison are presented. The space charge variation analysis was carried out under the applied electric field of 20 kV/mm at room temperature using the pulsed electro-acoustic technique (PEA). Based on the results, the charge density, electric field, and charge trap distribution were deduced. It is concluded that the space charge concentration and enhancement in the electric field of the aged material increases with aging duration and it is maximum in the case of 60 min corona-aged pure silicone rubber. Analysis of the recovery of the charge dynamics of the sample after corona discharges at the different time intervals shows that the recovery of trap distribution is faster for a virgin sample and slower for the sample with 5 wt% of alumina

Validated RP-HPLC Method for Analysis of Aripiprazole in a Formulation

A rapid, simple and validated reversed-phase high-performance liquid chromatographic method has been developed for analysis of aripiprazole in tablet dosage form. Aripiprazole was separated on an ODS analytical column with a 40:60 (v/v) mixture of acetonitrile and triethanolamine buffer (5 mM, pH 3.5 ± 0.05 adjusted by addition of 85% phosphoric acid) as mobile phase at a flow rate of 1.5 mL min-1. The effluent was monitored by UV detection at 254 nm. Calibration plots were linear in the range of 20 to 60 µg mL-1 and the LOD and LOQ were 0.411 and 1.248 µg mL-1, respectively. The high recovery and low relative standard deviation confirm the suitability of the method for routine quality control determination of aripiprazole in tablets

Kalaichelvi R, UV Spectrophotometric Method for Determination of Cinitapride in Pure and its Solid Dosage. E-Journal of Chemistry

ABSTRACT A simple, sensitive and reproducible spectrophotometric method was developed for the determination of clebopride in pure form and in pharmaceutical formulation. It has an absorption maximum at 263 nm and obeys beer's law in the concentration range 20 -100 µg mL -1 . Results of analysis were validated statistically and by recovery studies. The apparent molar absorptivity and sandell's sensitivity were 3.944x10 3 L mol -1 cm -1 and 1.06x10 -5 µg cm -2 , respectively. The slope and intercept of the equation of the regression line are 0.0106 and 0.0045 respectively. Correlation coefficient was found to be 0.9999. This method is successfully employed for the determination of clebopride in pharmaceutical preparation

Simple Extractive Colorimetric Determination of Oxaprozin by Acid-Dye Complexation Methods in Solid Dosage Form

A simple and sensitive extractive spectrophometric method has been described for the assay of oxaprozin (OXA) either in pure form or in pharmaceutical solid dosage form. The developed method involves formation of colored chloroform extractable ion-pair complex of OXA with bromocresol green in aqueous acidic medium. The extracted complexes showed absorbance maxima at 421 nm. Beer's law is obeyed in the concentration range of 10-50 μg mL-1. This method has been applied to the determination of drug in commercial tablets. Results of analysis were validated statistically. The excipients present in the formulations do not interfere with the assay procedure

UV Spectrophotometric Determination of Aripiprazole in Bulk and Pharmaceutical Formulation

A simple, sensitive and reproducible spectrophotometric method was developed for the determination of aripiprazole in pure form and in pharmaceutical formulation. It has an absorption maximum at 219 nm and obeys beer's law in the concentration range 2- 10 µg mL-1. Results of analysis were validated statistically and by recovery studies. The apparent molar absorptivity and sandell's sensitivity were 5.2 x 105 L mol-1 cm-1 and 8.4 x 10-3 µg cm-2, respectively. The slope and intercept of the equation of the regression line are 0.0035 and 0.1155 respectively. Correlation coefficient was found to be 0.9998. This method is successfully employed for the determination of aripiprazole in pharmaceutical preparation

UV Spectrophotometric Estimation of Acipimox inBulk and Capsule Dosage Form

A new simple, rapid, accurate, sensitive and precise spectrophotometric method in ultra violet region has been developed for determination of acipimox (ACX) in bulk and capsule dosage form. Acipimox exhibited maximum absorbance at 231 nm with apparent molar absorptivity of 1.5104 × 104 in distilled water. Beer’s law was found to be obeyed in the concentration range 1-10 μg mL-1. Correlation coefficient was found to be 0.9998. The developed method was validated respect to linearity, precision, accuracy. The proposed method is useful for the routine estimation of ACX in bulk and capsule dosage form

UV Spectrophotometric Method for Determination of Cinitapride in Pure and its Solid Dosage Form

A new, rapid, precise, accurate and sensitive analytical method was developed for the UV spectrophotometric assay of cinitapride (CTP). The drug obeyed the Beer's law and showed good correlation. It showed absorption maxima at 260 nm in methanol. The linearity was observed between 5-40 µg mL-1. The results of analysis were validated by recovery studies. The recovery was more than 99%. The proposed method is the only method available for spectrophotometric determination of the drug. It is simple, precise, sensitive and reproducible and can be used for the routine quality control testing of the marketed formulations