Development and validation of a stability-indicating RP-HPLC assay method of Verapamil, its suitability for impurity analysis and characterization of degradation impurities by LC-MS/MS

Pramod Kumar Ragham and Kothapalli B. Chandrasekhar

A validated stability indicating RP-HPLC assay of Verapamil was developed by separating its degradants on X-Bridge C18 (150*4.6mm, 5µ) column using 10 mM ammonium acetate at pH 5.5 and 0.02% TEA in acetonitrile as a mobile phase in a gradient elution mode at a flow rate of 1.0 mL/min. The detection was monitored at 230 nm. The method was validated in terms of accuracy, precision, linearity and robustness as per ICH guidelines for assay of Verapamil. Forced degradation studies were performed on bulk sample of verapamil as per ICH prescribed stress conditions using acid, base, oxidative, water hydrolysis, thermal stress and photolytic degradation to show the stability indicating power of the method. Significant degradation was observed during oxidative stress and the degradation product formed was identified by LCMS/MS and no degradation was observed in other stress conditions. The limits of detection and quantification of Verapamil were 0.13 and 0.40 µg/ml respectively. The method was successfully developed and validated to quantify related impurities of Verapamil in bulk drugs. Here it is assumed that the Response factors for the impurities could be equal to the response of Verapamil and considering this, the verapamil at a level of 0.1% specification, the precision, linearity, accuracy and robustness studies were performed. This single method is better applicable for both analysis of assay and related impurities of Verapamil.

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Investigating the replacement of Quick Lime with Ferric Chloride in Quchan Water Treatment System

Golestani Alizadeh H. and Jafarabadi Sadeghi F.

Raw water typically contains high suspending solids content, bacteria, algae and organic material and in some areas, raw water can be very hard. Chemical precipitation is one of the basic treatment processes to treat hard and turbid water. In Quchan, water treatment system inlet water has turbidity and it is very hard; the only coagulant used to remove turbidity is ferric chloride, so the treated water remains very hard. The goal of this experimental work is to replace quick lime with ferric chloride to reduce both turbidity and hardness. The experimental results show that ferric chloride and quick lime can reduce both turbidity and hardness for each of the two kinds of raw water. But the effect of quick lime on hardness removal is more than the ferric chloride and the hardness can be reduced below 500 mg/l. So it can be concluded that the replacement of ferric chloride with quick lime can be used as a suitable way to reduce both turbidity and hardness for Quchan water treatment system.

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Optimum Dodecanol-detergent foam performance for formulation of eco-friendly surfactants

Chattopadhyay Pradipta and Karthick R. Arun

Optimum foam performance is of tremendous importance from the standpoint of formulation of biodegradable, environmental friendly surfactants. To gain deeper understanding on foams required for judging such surfactants, aqueous foams generated by the use of mixtures of dodecanol, n-butanol and popular detergent Surf Excel were first characterized using a Dynamic Foam Analyzer DFA 100 (Kruss GmbH, Germany) for parameters like foam capacity and RMI 30. Mathematical models for foam capacity and RMI 30 were developed by using the Central Composite Experimental Design (CCD) approach of Response Surface Methodology and then statistically analyzed and validated. The responses obtained in the study were foam capacity (FC) and RMI 30 in mL. Numerical optimization for the responses, using the model equations developed, was performed by using Design-Expert Software version 9.0.4.1. The optimum values of responses FC and RMI 30 were found to be in reasonable agreement with the experimental results.

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Mitigating the Environmental Pollution in Diesel Engine using Hydrotreated Vegetable Oil

Hemanandh J., Narayanan K.V., Lavanya M. and Meenakshi Sundaram A.

The present study investigates the use of hydrotreated vegetable oil as fuel and analyzes the emission and performance characteristics of the kirloskar Direct Injection 4 – stroke Diesel engine, air-cooled single cylinder, 4.4 kw, constant speed of 1500 rpm, and compression ratio 17.5:1. The Refined Palmolein oil was hydrotreated using Ni-Mo/Al2O3 as catalyst at 60 bar and 360°C. The hydrotreated refined palmolein oil was used as a fuel. The properties of petro diesel, FAME, and hydro treated refined palmolein oil were compared with Euro IV Indian standards. The experiments were conducted systematically by blending the hydro treated refined palmolein oil by 25% (B25) and 100% (B100) by volume and at different loads such as 0%, 25%, 50%, 75%, and 100%. The emission (CO, HC, NOx and FSN), performance (BSFC and BTE) and combustion analysis were measured. The experimental results showed that there was reduction in CO, HC, NOx and BSFC while there was increase in BTE when compared with petro diesel fuel. The combustion pressure and heat release rate (HRR) for B100 were almost equal to those of diesel. No modification was required in the diesel engine.

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Antimicrobial Activity of Schiff’s Base of Acylated Hydrazine Derivatives of Mercapto-heterocyclic Compounds

Saravanan Dhandayutham, Mohan Singaravel, Ananthan Sarkkari and Shekhawat Anita

Heterocycles bearing nitrogen, sulphur and oxygen moieties constitute the core structure in a number of biologically interesting compounds. Reaction of acylated hydrazine derivatives of mercapto-heterocyclic compounds with substituted aromatic aldehyde afforded Schiff’s base of acylated hydrazine derivative. Tetrazoles, thiadiazoles, oxadiazoles which are structural subunits of these heterocyclic compounds make them biologically active compounds. Schiff”s bases have potential biological activity. Hydrazine derivatives are important and versatile reagents, especially, for the synthesis of Schiff’s base from substituted benzaldehyde derivatives. The generality of this reaction is extended to various mercapto-heterocyclic compounds. In the present communication, the antimicrobial activity of various substituted benzaldehyde derivatives with heterocyclic moieties is reported.

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Utilization of Natural Dyes for Dye-Sensitized Solar Cells based on Nanoscale Titanium dioxide – Working Principle, Fabrication and Characterization

Vyjayanthi J.P.

Taking into account the current scenario of dwindling natural conventional energy resources and the socio-economic problems associated with it, immense research is being undertaken in finding a suitable environment-friendly alternative which must be cost-effective, efficient and feasible with respect to field-scale applications. Dye-sensitized solar cells (DSSCs) are one of the most potential photovoltaic devices. They have gained incredible interest as a suitable substitute to conventional renewable energy sources which can be attributed to two main factors, namely, their high solar energy conversion efficiency and relatively low fabrication cost. This study mainly focuses on the underlying principles governing dye-sensitized solar cells with special emphasis on the use of dyes extracted from natural plant sources as photosensitizers. The study also outlines the procedure followed for fabrication and characterization of solar cells using natural dyes and also highlights improvements in the efficiency of DSSCs as reported in selective studies carried out recently. The performance of the fabricated cells with respect to their conversion efficiency has been discussed and it has been observed that with few modifications in the underlying factors affecting their efficiency, dye-sensitized solar cells could drive the green energy revolution to overcome an impending energy crisis across the globe.

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