NOPR Collection:

Extractive spectrophotometric methods for determination of terbinafine hydrochloride in pharmaceutical formulations using some acidic triphenylmethane dyes

Tue, 01 May 2012 00:00:00 GMT

Title: Extractive spectrophotometric methods for determination of terbinafine hydrochloride in pharmaceutical formulations using some acidic triphenylmethane dyes Authors: Chennaiah, M; Veeraiah, T; Kumar, T Vinod; Venkateshwarlu, G Abstract: Three simple and sensitive extractive spectrophotometric methods have been described for the assay of terbinafine hydrochloride either in pure form or in pharmaceutical formulations. The developed methods involve formation of coloured chloroform extractable ion-pair complexes of the drug with bromothymol blue (BTB), bromophenol blue (BPB) and bromocresol green (BCG) in acidic medium. The extracted complexes show absorbance maxima at 410 nm for all three methods. Beer’s law is obeyed in the concentration ranges 2.0-25, 2.0-25 and 2.0-25 µg/mL with BTB, BPB and BCG respectively. The effects of concentration of dye, pH, and interference of excipients have been studied and optimized. The limits of detection and quantification have been determined for three methods. All the three methods have been validated as per the guidelines of ICH. The methods have been applied for the determination of drug in commercial tablets and the results of analysis are validated statistically through recovery studies. Page(s): 218-221

Pretreatment of coffee pulping wastewater by Fenton’s reagent

Tue, 01 May 2012 00:00:00 GMT

Title: Pretreatment of coffee pulping wastewater by Fenton’s reagent Authors: Kumar, B Manoj; Ulavi, Savitha U; Ramesh, H S; Asha, G; Pallavi, R Abstract: The present study deals with treatment of coffee pulping wastewater using Fenton’s oxidation process. The coffee pulping wastewater used for the present study is characterized by low pH with high concentration of COD, ammonia nitrogen, nitrate nitrogen and phosphorous with BOD/COD ratio varying from 0.037 to 0.050. The effect of different operating conditions, namely Fenton dosage, mixing speed, pH and reaction time, is evaluated. Working with the wastewater pH of 6.42, mixing speed of 25 RPM, molar ratio of 12.43 and mass ratio of 0.60 for reaction time of 60 min makes possible the COD conversion of 84.39%. The percentage removal of other pollutant parameters, such as ammonia nitrogen, nitrate nitrogen and phosphorous, is found to be 90.75, 57.5 and 80% respectively. Page(s): 213-217

Spectrophotometric determination of quetiapine fumarate through ion-pair complexation reaction with tropaeolin ooo

Tue, 01 May 2012 00:00:00 GMT

Title: Spectrophotometric determination of quetiapine fumarate through ion-pair complexation reaction with tropaeolin ooo Authors: Vinay, K B; Revanasiddappa, H D Abstract: A sensitive, rapid and reproducible spectrophotometric method for the determination of quetiapine fumarate (QTF), an antipsychotic drug, in bulk drug, tablets and human urine has been developed and validated. The method includes the formation of a 1:2 chloroform extractable ion-pair complex between the drug and the dye tropaeolin ooo (TP) in acidic medium (pH 1.83±0.03). The resulting orange-red coloured ion-pair complex exhibits an absorption maximum at 480 nm. The optimum conditions for the ion-pair formation have also been established. The method permits the determination of QTF over a concentration range 2.0 – 20.0 µg mL^-1. The apparent molar absorptivity and Sandell sensitivity values are found to be 2.30 × 10⁴ Lmol^-1cm^-1 and 0.0264 µg cm^-2 respectively. The limits of quantitation and detection values are also reported. The accuracy and precision results of the method evaluated on intra-day and inter-day basis are found to be satisfactory. The proposed method has been successfully applied to the determination of QTF in bulk drug, tablets and spiked human urine with satisfactory results. The excipients from the tablets and other basic substances present in urine do not interfere in the assay. Page(s): 205-212

Theoretical and electrochemical studies on the effect of substitution on 1, 2, 4- triazole towards mild steel corrosion inhibition in hydrochloric acid

Tue, 01 May 2012 00:00:00 GMT

Title: Theoretical and electrochemical studies on the effect of substitution on 1, 2, 4- triazole towards mild steel corrosion inhibition in hydrochloric acid Authors: John, Sam; Joseph, Abraham Abstract: The present paper reports study on the inhibition of mild steel in 0.5 M HCl with different concentrations of substituted 1,2,4-triazoles using conventional weight loss method, potentiodynamic polarization studies, linear polarization studies, electrochemical impedance spectroscopy and quantum chemical calculations. The theoretical study has been initiated using density functional theory at the B3LYP/6-31G (d) level in order to elucidate the inhibition efficiencies and reactive sites of these inhibitor molecules. The efficiencies of corrosion inhibitors and the global chemical reactivity relate to some parameters, such as E_HOMO, E_LUMO, gap energy (ΔE), electronegativity (χ), global hardness (η) and the fraction of electrons transferred from inhibitor molecule to the metal atom (ΔN). The calculated results are in good agreement with the experimental data on the whole. In addition, the local reactivity has been analyzed through the Fukui function and condensed softness indices. Results show that the corrosion rate decreases and inhibition efficiency increases with inhibitor concentration. The results of polarization studies reveal that the additive acts as a mixed type inhibitor. The surface adsorption of inhibitor molecules decreases the double layer capacitance and increases the polarization resistance. Page(s): 195-204