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Determination of nortriptyline hydrochloride in bulk and pharmaceutical formulations

Kumar R. S., Manjunatha D. H., Seetharamappa J., Harikrishna K., Shaikh S. M. T.

Chemia Analityczna

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2007

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Vol. 52, No. 2

337-346

EN

wo simple, fast, and sensitive extractive spectrophotometric methods for determination of nortriptyline hydrochloride (NTPH) in pure and pharmaceutical formulations have been developed. These methods are based on the formation of chloroform-soluble ion-association complexes of NTPH and bromopheno! blue (BPB) and bromopyrogallol red (BPR) in NaOAc-HCi buffer of pH 3,29. Absorption maxima of both complexes were recorded at 410 nm and at 425 nm, respectively for BPB and BPR. Reaction conditions were optimized to obtain the maximum color intensity. The systems obeyed Beer's law in the analyte's concentration ranges of 0.1-7.2 μ mL-1 and 0.5-23.4 μ mL-1 for BPB and BPR, respectively. The proposed methods are simple, accurate, and suitable for analysis of pharmaceutical formulations.

PL

Opracowano dwie proste, szybkie i czule spektrofotornetryczne metody oznaczania chlorowodorku nortryptyliny (NTPH) w postaci związku chemicznego i preparatu farmaceutycznego. Metody te polegająna tworzeniu rozpuszczalnych w chloro formie jonowoasocja-cyjnych kompleksów NTPH z błękitem bromofenolowym (BPB) i z czerwienią bromopiro-gallolową (BPR) w buforze NaOAc-HCl o pH = 3,29. Maksima absorpcj i obu kompleksów rejestrowano przy 410 i 425 nm, odpowiednio dla BPB i BPR. Warunki reakcji optymalizowano tak aby uzyskać maksimum intensywności barwy. Ukiad spełnia prawo Beera w zakresie stężeń analitów 0,1-7,2 μ mL-1 i 0,5-23,4 μ mL-1, odpowiednio dla BPB i BPR. Zaproponowana metoda jest prosta, dokładna i można ją stosować do analizy preparatów farmaceutycznych.

2

Fluorescence and Circular Dichroism Studies on the Interaction of Brmocresol Purple with Bovine Serum Albumin

Kamat B., Seetharamappa J.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 5

723-732

EN

The mechanism of interaction of bromocresol purple (BCP) with bovine serum albumin (BSA) has been investigated by spectrofluorometric and circular dichroism methods. Association constant for the BCP-BSA system showed that the interaction is non-covalent in nature and that there occurs only a partial occupation of a binding site. Binding studies in the presence of hydrophobic probe, 8-anilino-1-naphthalene sulphonic acid, sodium salt (ANS) showed that there is hydrophobic interaction between BCP and ANS and they may share common sites in BSA. Stern-Volmer analysis of fluorescence quenching data showed that the fraction of fluorophore (protein) accessible to the quencher (BCP), was close to unity, indicating thereby that both tryptophan residues of BSA are involved in dye-protein interaction. The rate constant for quenching, greater than 1010M-1s-1, indicated that the dye binding site is in close proximity to tryptophan residue of BSA. Thermodynamic parameters, obtained from data at different temperatures, showed that the binding of BCP to BSAinvolves hydrophobic bonds predominantly. Fluorescence intensity data in the presence of additives showed that hydrophobic interaction plays a prominent role. Significant decrease in concentration of free dye was observed for BCP in presence of paracetamol. Circular dichroism studies revealed the change in helicity of BSA, due to binding of BCP to BSA.

3

Spectrofluorimetric determination of cetirizine hydrochloride in pharmaceutical preparations

Melwanki M. B., Seetharamappa J., Gowda B. G., Sajjan A. G.

Chemia Analityczna

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2001

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Vol. 46, No. 6

883-887

EN

A rapid and simple fluorimetric procedure for the determination of trace amounts of cetirizine hydrochloride in pharmaceutical formulations has been developed. The measurement of the fluorescence intensity was performed at 297 nm after excitation at 230 nm. The fluorescence intensity is a linear function of concentration of cetirizine hydrochloride up to 16 ug ml(-1) . The detection limit was found to be 0.31 ng ml(-1).

PL

Opracowano szybką i prostą spektrofluorymetryczną metodę oznaczania chlorowodorku cetyryzyny w substancji i w preparatach farmaceutycznych. Pomiary intensywności fluorescencji wykonywano przy długości fali 297 nm po wzbudzeniu przy 230 nm. Stwierdzono, że intensywność fluorescencji jest liniową funkcję stężenia cetyryzyny do 16ug ml(-1). Granica wykrywalności wynosi 0.31 ng ml (-1)"'.