scholarly journals Protolytic equilibria in homogeneous and heterogeneous systems of ketoconazole and its direct spectrophotometric determination in tablets

2005 ◽  
Vol 70 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Mirjana Vojic ◽  
Gordana Popovic ◽  
Dusan Sladic ◽  
Lidija Pfendt
Keyword(s):  
Ionic Strength ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Equilibrium Constants ◽  
Heterogeneous Systems ◽  
Water Systems ◽  
Acidity Constant ◽  
Acid Base ◽  
Protolytic Equilibria

The acid-base equilibria of a diprotic, slightly hydrosoluble base ketoconazole were studied in homogeneous and heterogeneous water systems. The determinations were performed at 25?C at a constant ionic strength of M(NaCl). The acidity constant Ka1 was determined by potentiometric (pKa1 3.20) and spectrophotometric (pKa1 3.26) methods. A pKa2 constant of 6.10 was obtained based on the equilibrium constants pKs0 4.84 and pKs1 -1.26, determined in a heterogeneous ketoconazole system. The obtained values of the constants served to calculate the solubility and the distribution of the equilibrium forms of ketoconazole as a function of pH. On the basis of the distribution of the equilibrium forms of ketoconazole, a spectrophotometric method for the determination of its content in commercial tablets was developed. The determinations were performed at 225 nm in 0.1 M HCl. The method is simple and rapid and enables the direct spectrophotometric determination of the content of ketoconazole without previous isolation.

Spectrophotometric study of the acid-base and optical properties of the 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-(diethylamino)phenol (BrPADAP, ClPADAP) and their complexation equilibria with zinc(II) ions

1982 ◽  
Vol 47 (10) ◽  
pp. 2676-2691 ◽  
Author(s):  
Miroslav Macka ◽  
Vlastimil Kubáň
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Alkaline Media ◽  
Acid Base ◽  
Ethanol Medium ◽  
Triton X ◽  
Mixed Water ◽  
Derivatives Of

The optical and acid-base characteristics of BrPADAP and ClPADAP were studied in mixed water-ethanol and water-DMF media and in 10% ethanol medium in the presence of cationic, anionic and nonionic tensides. The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the ML and ML2 complexes with zinc(II) ions were found by graphical analysis and numerical interpretation of the absorbance curves by the modified SQUAD-G program. Optimal conditions were found for the spectrophotometric determination of Zn(II) in the presence of 0.1% Triton X-100 or 1% Brij 35 in alkaline media with pH = 6.5-10. BrPADAP and ClPADAP are the most sensitive reagents (ε = 1.3-1.6 . 105 mmol-1 cm2 at 557 and 560 nm, respectively) for the determination of zinc with high colour contrast of the reaction (Δλ = 104 nm) and selectivity similar to that for the other N-heterocyclic azodyes (PAN, PAR, etc.).

Collaborative Study of the Spectrophotometric Determination of Procainamide Hydrochloride

1976 ◽  
Vol 59 (4) ◽  
pp. 807-810
Author(s):  
Jeffrey C Hamm
Keyword(s):  
Sodium Hydroxide ◽  
Acid Medium ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Dosage Forms ◽  
Standard Deviations

Abstract The USP analysis for procainamide HCl is titrimetric and relatively nonspecific, capsule and tablet dyes may interfere, and the method is not applicable to coated tablets. In the spectrophotofluorometric method the sample deteriorates when exposed to a xenon source. In the ultraviolet spectrophotometric method reported here, the sample is dispersed in acid medium, possible interferences are extracted in chloroform, base is added, procainamide is extracted in chloroform, the residue is dissolved in sodium hydroxide, and the compound is measured by absorption at 272 nm and comparison with a standard. Recoveries of standards added to capsule, tablet, and injection composites ranged from 99.3 to 102%. Twelve collaborators reported duplicate assay results for all 3 dosage forms with per cent standard deviations for 5 samples ranging from 1.01 to 1.27%. The method has been adopted as official first action.

SOME EQUILIBRIUM CONSTANTS OF TRANSITION METAL HALIDES

1960 ◽  
Vol 38 (10) ◽  
pp. 1827-1836 ◽  
Author(s):  
M. W. Lister ◽  
P. Rosenblum
Keyword(s):  
Ionic Strength ◽  
Transition Metal ◽  
Equilibrium Constant ◽  
Spectrophotometric Method ◽  
Equilibrium Constants ◽  
Cell Voltage ◽  
Metal Halides ◽  
Complex Ions ◽  
Anomalous Variation ◽  
A Cell

Measurements are reported on the formation of complex ions in solutions containing cupric and chloride or bromide ions, and solutions of nickel or cobalt with chloride. In each case the halide was present in very low amount. With copper a spectrophotometric method was used, and a cell voltage method with nickel and cobalt. The ionic strength was kept constant, but the temperature was varied. The data show difficulties of interpretation if it is assumed that only MX+ ions (M is the metal, X is the halogen) are formed, the difficulties arising from the anomalous variation of the equilibrium constant with temperature, and from the general drift of the calculated constants from the e.m.f. measurements. Various explanations are considered and it is shown that postulation of M2X+3 ions is at least a possible explanation.

scholarly journals DETERMINATION OF TRACE NITRITE AS 4-(4-NITROBENZENAZO)- 1-AMINONAPHTHALENE COMPLEX BY EXTRACTION-SPECTROPHOTOMETRY

2010 ◽  
Vol 9 (2) ◽  
pp. 254-260
Author(s):  
Choirul Amri ◽  
Dwi Siswanta ◽  
Mudasir Mudasir
Keyword(s):  
Detection Limit ◽  
Organic Solvents ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Absorbance Unit ◽  
Extraction Spectrophotometry ◽  
Linear Concentration

A study of extraction-spectrophotometric method for the determination of trace nitrite as 4-(4-nitrobenzenazo)-1-aminonaphthalene complex using n-amylalcohol and chloroform as organic solvents has been done. Results of the study showed that extraction-spectrophotometric determination of nitrite using n-amylalcohol or chloroform was very sensitive and had low limit of detection. Extraction-spectrophotometric method of nitrite using n-amylalcohol gave range of linear concentration 0.000-0.054 mg/L NO2--N, detection limit of 2.09x10-4 mg/L NO2--N, and sensitivity of 34.514 ± 0.398 absorbance unit per mg/L of NO2--N. Meanwhile, extraction-spectrophotometric of nitrite using chloroform had range of linear concentration of 0.000-0.100 mg/L NO2--N, detection limit of 8.99x10-4 mg/L NO2--N, and sensitivity of 18.353 ± 0.456 absorbance unit per mg/L NO2--N.   Keywords: Nitrite Trace, 4-(4-Nitrobenzenazo)-1-Aminonaphthalene, Extraction-Spectrophotometry

scholarly journals Difference spectrophotometric method for the determination of Fluphenazine hydrochloride in tablets using peroxomonosulfate

2021 ◽  
Vol 9 (2) ◽  
pp. 64-71
Author(s):  
Mykola Blazheyevskiy ◽  
◽  
Valeriy Moroz ◽  
Olena Mozgova ◽  
◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Present Method ◽  
Molar Absorptivity ◽  
Limit Of Quantification ◽  
Derivatizing Agent ◽  
Sensitive Method

The oxidative derivatization method using potassium hydrogenperoxomonosulfate for the indirect spectrophotometric determination of Fluphenazine hydrochloride is presented. Potassium hydrogenperoxomonosulfate is introduced as a derivatizing agent for Fluphenazine hydrochloride, yielding the sulfoxide. This reaction product was successfully used for the spectrophotometric determination of the Fluphenazine hydrochloride. The UV spectroscopic detection of the sulfoxide proved to be a more robust and sensitive method. The elaborated method allowed the determination of Fluphenazine hydrochloride in the concentration range of 0.2-30 µg mL-1. The molar absorptivity at 349 nm is 5.6×103 (dm3cm-1mol-1). The limit of quantification, LOQ (10S) is 0.24 µg/mL. A new spectrophotometric technique was developed and the possibility of quantitative determination of Fluphenazine hydrochloride in tablets 5.0 mg was demonstrated. The present method is precise, accurate and excipients did not interfere. RSD for Fluphenazine Hydrochloride 5.0 mg tablets was 1.37 %.

scholarly journals Spectrophotometric Determination of Epinephrine in Pharmaceutical Preparations Using Praseodymium as Mediating Metals

2011 ◽  
Vol 8 (1) ◽  
pp. 110-117 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Relative Error ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Pharmaceutical Preparations ◽  
Direct Methods ◽  
Orange Yellow ◽  
Sensitive Spectrophotometric Method

A simple, accurate and sensitive spectrophotometric method for the determinaion of epinephrine is described . The method is based on the coordination of Pr (III) with epinephrine at pH 6. Absorbance of the resulting orange yellow complex is measured at 482 nm . A graph of absorbance versus concentrations shows that beer 's low is obeyed over the concentration range (1-50)mg.ml-1 of epinephrine with molar absorpitivity of ( 2.180x103 L.mol-1.cm-1 ), a sandell sensitivity of (0.084 mg.cm-2 ), a relative error of (-2.83%) , a corrolation coffecient (r= 0.9989) and recovery % ( 97.03 ± 0.75 ) depending on the concentration.This method is applied to analyse EP in several commercially available pharmaceutical preparations using direct methods .All statistical calculations are implemented via a Minitab software version 11.

The Direct Spectrophotometric Determination of Protein in Cerebrospinal Fluid

1963 ◽  
Vol 9 (3) ◽  
pp. 283-295 ◽  
Author(s):  
Roman L Patrick ◽  
Ralph E Thiers
Keyword(s):  
Cerebrospinal Fluid ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Gel Filtration ◽  
Spectrophotometric Measurement ◽  
Separation Chamber ◽  
Cerebrospinal Fluid Protein

Abstract A rapid and sensitive direct spectrophotometric method for the determination of cerebrospinal fluid protein which uses as little as 0.1 ml. of sample has been described. The result is not affected by the ratio of albumin to globulin in the sample. Interfering substances are removed prior to spectrophotometric measurement with an automatic separation chamber employing the principle of gel filtration. Slight alterations of the procedure described for the measurement of protein enable one to obtain the nonprotein moiety for study or to measure proteins in other biologic fluids.

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