Metoprolol tartrate is a selective b-adrenergic antagonist, which is used in the treatment of cardiovascular disorders such as hypertension, angina pectoris, cardiac arrhythmias and myocardial infarction. The drug is quite sensitive, even a small dose of the drug gives sufficient blockade. Since the bblockers are also misused as doping agents in sports and therefore these drugs have been added to the list of forbidden drugs by the International Olympic Committee (IOC). 1)Therefore the development of an analytical method for the determination of metoprolol tartrate is of great significance.The assay of the drug is listed in the monograph of British Pharmacopoeia, which describes a potentiometric titration method.2) Several analytical methods have been developed for the determination of metoprolol in biological fluids and pharmaceutical formulations based on high performance liquid chromatography, [3][4][5][6][7][8][9][10][11] gas chromatography, 12,13) capillary electrophoresis, 14) thin layer chromatography, 15,16) infrared spectroscopy, 17) and electrochemical methods. 18,19) The above mentioned techniques are sensitive but expensive and require laborious clean up procedure prior to analysis. Spectrophotometry is the technique of choice even today due to its inherent simplicity and therefore frequently used in the laboratories of the developing countries to overcome versatile analytical problem. The drug has been determined in the visible region based on ion-pair formation between drug and reagents like oxidized quercetin 20) ; bromophenol blue, bromocresol purple, bromocresol green ; and carbon disulfide-copper chloride. 24)The charge transfer complexation reactions of metoprolol tartrate with s and p-acceptors 24,25) have also been utilized for its quantification in pharmaceutical formulations. Shingbal and Bhangle 26) have reported a spectrophotometric method based on the reaction of drug with 2,4-dinitrofluorobenzene in HCl/dioxan medium to form a colored chromophore, which absorbs maximally at 380 nm. The quantification of metoprolol tartrate was done on treatment of the drug with ammonium metavanadate, 27) FeCl 3 , 28) N-bromosuccinimide, 29) and a mixture of KNO 3 and H 2 SO 4 followed by addition of alkali to get colored chromophore.30) The literature is still poor in analytical procedures based on kinetic spectrophotometry for the determination of drug in pharmaceutical preparations. There is, therefore, a need for a simple and sensitive kinetic spectrophotometric method for the determination of metoprolol tartrate in pharmaceutical formulations. It was found that potassium permanganate oxidizes the metoprolol in alkaline medium and this reaction has not been used before to quantify the drug spectrophotometrically. This paper describes a simple and sensitive kinetic spectrophotometric method for the determination of metoprolol tartrate in drug formulations. The method involves the oxidation of drug with alkaline potassium permanganate at 25Ϯ1°C and subsequent measurement of absorbance at 610 nm. The in...

Recebido em 26/2/11; aceito em 18/7/11; publicado na web em 19/8/11A spectrophotometric method based on the formation of ion-pair complex between haloperidol and eriochrome black T (EBT) at pH 1.85 has been described. The formed complex was extracted quantitatively into chloroform and measured at 510 nm. Infra red (IR) studies were performed to confirm the formation of ion-pair complex. Beer's law was obeyed in the concentration range of 2.0-9.0 μg mL -1 with molar absorptivity of 2.67 × 10 4 L mol -1 cm -1 . The detection limit was found to be 0.18 μg mL -1 . Statistical comparison of the results of the proposed method with those of the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.

Globally, dyes are widely used in the pharmaceutical, food, textile, cosmetics, plastics, leather, paint, ink and paper industries. Eosin is an acidic orange-pink dye and has very strong staining properties. Haematoxylin and eosin Y (H and E) combination is the most common staining and primary diagnostic technique in histo-pathological laboratories. This review mainly discussed the utility of eosin dye in quality control laboratories as an ion pairing agent for drug analysis. Eosin Y is one the most common ion pairing agent and its mono and di anionic forms are capable of interacting with many drug molecules to form colored/fluorescent binary or ternary complexes that can be analyzed with or without extraction by spectrofluorimetry and/or spectrophotometry. Quenching fluorescence and advantages of spectrofluorimetry over spectrophotometry were also discussed. Fluorescence detection greatly enhances the sensitivity and providing a sensitive and relatively inexpensive instrumental method of analysis using eosin Y for various important drugs in pure, commercial dosage forms and biological fluids.

In this paper, the applications of thermoplastic, thermoset polymers, and a brief description of the functions of each subsystem are reviewed. The synthetic route and characteristics of polymeric materials are presented. The mechanical properties of polymers such as impact behavior, tensile test, bending test, and thermal properties like mold stress-relief distortion, generic thermal indices, relative thermal capability, and relative thermal index are mentioned. Furthermore, this paper covers the electrical behavior of polymers, mainly their dielectric strength. Different techniques for evaluating polymers’ suitability applied for electrical insulation are covered, such as partial discharge and high current arc resistance to ignition. The polymeric materials and processes used for manufacturing cables at different voltage ranges are described, and their applications to high voltage DC systems (HVDC) are discussed. The evolution and limitations of polymeric materials for electrical application and their advantages and future trends are mentioned. However, to reduce the high cost of filler networks and improve their technical properties, new techniques need to be developed. To overcome limitations associated with the accuracy of the techniques used for quantifying residual stresses in polymers, new techniques such as indentation are used with higher force at the stressed location.

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