Simultaneous Determination of Adrenaline and Noradrenaline by First Derivative Spectrophotometry in a Fia Assembly

Abstract

This article deals with the design of an unsegmented-flow injection manifold for the simultaneous determination of adrenaline and noradrenaline two structurally related compounds with overlapping spectra. An FIA manifold is proposed for the simultaneous determination in which the sample solution is directly injected into a carrier-reagent stream of aqueous NaOH. The selected wavelengths (first derivative) were 394 and 342 nm, for noradrenaline and adrenaline, respectively with an integration time of 0.4 s. The calibration graphs are linear over the range 2.0–30 ppm for both drugs. The method is applied to different synthetic mixtures of both drugs.     

Determination of Some Cephalosporins Using Derivative Spectrophotometry

Abstract

A rapid and simple method for the determination of cephalexin, cephalothin sodium and cephradin without prior separation from their alkali-induced degradation products is presented. By measuring the values of the first and second derivative spectra at certain wavelengths, the concentration of the intact drug can be calculated directly without interference of degradation products. The method was proved using synthetic mixtures of the intact drugs with their degradation products, and its suitability to monitor the stability of the drugs was demonstrated.     

Second-Derivative Spectrophotometric Determination of Some Benzenoid Drugs

Abstract

A rapid second-derivative spectrophotometric assay procedure has been described for the determination of some benzenoid drugs in pharmaceutical dosage forms. Spectral interference from formulation excipients in simple uv spectrophotometric methods has been eliminated by the application of the proposed method. The different assay parameters, linearity and precision of the method have been assessed. The assay results obtained for eight batches of the pharmaceutical formulations of these drugs are in accord with the declared amounts. The high specificity, ease and simplicity offered by second-derivative spectrophotometry permit unit dose assay of these formulations.     

Multicomponent Chemometric Determination of Colorant Mixtures by Voltammetry

Abstract

A quantitative chemometric approach, iterative target transformation factor analysis (ITTFA), was applied to the simultaneous determination of mixtures of four food colorants (Amaranth, Sunset Yellow. Tartrazine and Ponceau 4R) by adsorptive voltammetry. The conventional and first-derivative voltammograms of the quaternary mixtures were used to perform the optimization of the calibration procedure by the ITTFA models. The proposed method was applied satisfactorily to the determination of a set of synthetic quaternary mixtures of colorant in phosphate/citric acid buffers (pH 5.7) and acceptable results were obtained. No significant advantages were found with the application of derivative technique in this voltammetric work.     

Spectrophotometric Determination of Etilefrine,Ritodrine, Isoxsuprine and Salbutamol by Nitration and Subsequent Meisenheimer Complex Formation

Abstract

A simple and sensitive colorimetric method has been developed for the determination of four phenolic drugs, namely, etilefrine hydrochloride, ritodrine hydrochloride, isoxsuprine hydrochloride and salbutamol sulphate. The method is, mainly, based on the nitration of the drug molecule followed by the subsequent formation of meisenheimer complex with a nucleophilic reagent (acetone) in alkaline medium. The experimental conditions leading to optimum chromogen intensity and stability were carefully studied and incorporated in the general procedure. Under the proposed conditions, the method was applicable over the concentration range of 4.8–16 μg ml^?1 for the four drugs. The suggested method was further applied for the determination of the studied drugs in bulk and pharmaceutical dosage forms. The results of the analysis were found to agree statistically with those obtained with either the official or the referee methods. The procedure is characterized by its simplicity with accuracy and precision.     

Colorimetric Determination of Some Important Hydrazine Derivatives

ABSTRACT

A simple and rapid colorimetric method for the determination of isoniazid, iproniazid phosphate, phenylhydrazine hydrochloride and hydrazine hydrate is described. The method is based on the formation of a Schiff base when these compounds react with 4-dimethylaminocinnamaldehyde and measurement of the condensed products at 370–555nm. The procedure has been successfully applied to the assay of the pharmaceutical preparations containing the studied drugs and hydrazine, and phenylhydrazine mixture, and the results are compared to the official methods. All the different experimental conditions are studied and incorporated into the procedure.     

Spectrophotometric Determination of Quintomycin Sulphate with Phloroglucinol

Abstract

A new absorptiometric procedure for the determination of quintomycin sulphate in complex galenical mixtures is proposed, based on the reaction of the sample compound with a mineral acid-containing phloroglucinol solution. Absorbance readings at 448 nm obey Lambert-Beer's law within the concentration range from 4. 0 to 32. 0 μg ml^?1. The method is operationally simple and has a good precision and an adequate selectivity.     

Determination of Procaine Penicillin G and Penicillin G by Second Derivative Spectrophotometry in Pharmaceutical Products

Abstract

“Zero-crossing” derivative spectrophotometry has been used for determining binary mixtures of penicillin G and procaine penicillin G.

The procedure is rapid, simple, nondestructive, and does not require resolutions of equations.

Calibration graphs are linear between 2.0 and 50.0 μg mL^?1 of the penicillin G at 226.0 nm, and between 2.0 and 100.0 μg mL^?1 of procaine penicillin G at 319.0 nm, in the presence of each other. A complete and exhausive statistical analysis of the experimental data was realized to demonstrate the validity of method. The method was successfully applied to assay commercial injections of these drugs.     

Sensitive Spectrophotometric Determination of Some Dibenzazepine Drugs with Diazotized P-Phenylenediamine Dihydrochloride

ABSTRACT

A simple, sensitive and selective spectrophotometric procedure was developed for the determination of imipramine hydrochloride, desipramine hydrochloride, clomipramine hydrochloride and trimipramine maleate belonging to dibenzazepine class of drugs. The method is based on the interaction of diazotized p-phenylenediamine dihydrochloride with the drug in sulphuric acid medium. The resulting chromophore was measured at 565 nm, and was stable for about 2.5 hr. The commonly encountered excipients and additives do not interfere with the determination. Dibenzazepine drugs can be determined in the range of 0.1-4.0 μg/ml, with a relative standard deviation of 1.92% for ten replicate measurement of 2.0 μg/ml dibenzazepine drugs. Results from the analysis of preformulations and commercial tablets by this procedure agree well with those of the official method.     

Kinetic-Turbidimetric Determination of Stachyose Based on Its Inhibitory Action on Sucrose Crystallization.

Abstract

The effects of 9 saccharides on the crystallization of sucrose have been comparatively studied with analytical purposes. A sensitive (detection limit 0.1 μg mL^?1) and simple kinetic turbidimetric procedure is used for determination of stachyose, based on its inhibitory action on the crystallization of sucrose. The supersaturated solutions of sucrose were prepared by addition of acetone to stable water sucrose solutions. The induction period of the crystallization process was turbidimetrically measured. Controlled constant stirring and temperature are convenient in order to obtain reproducible results. The method was applied to the determination of stachyose in synthetic mixtures.     

A Partial Least-Squares Multivariate Calibration Method for the Simultaneous Spectrophotometric Determination of Spironolactone,Canrenone and Hydrochlorothiazide

Abstract

An application of a partial least squares calibration method for the simultaneous spectrophotometric determination of spironolactone, canrenone and hydrochlorothiazide is suggested. The use of the PLS for the multicomponent spectrophotometric determination is demonstrated on the analysis of several synthetic mixtures. It was shown that is possible to resolve complex mixtures of     

First-Derivative Spectrophotometric Determination of a Mixture of Pirbuterol Hydrochloride and Butorphanol Tartrate

Abstract

Vierordt's method, its modified version and the first derivative method have been applied for the simultaneous determination of butorphanol tartrate and pirbuterol hydrochloride in laboratory mixtures of authemtic and dosage forms. The first derivative spectrophotometric method yields accurate and reprodeucible results for both drugs. Mean percent recoveries for butorphanol tartrate and pirbuterol hydrochloride in dosage forms were 100.54±0.84 and 100.42±1.27, respectively. Virrordt's method and its modified version have given unreliable results; the reasons behind have been discussed.     

Two-Wavelength Spectrophotometric Determination of Food Color Mixtures with the Function Generator

Abstract

Though the two-wavelength spectrophotometric determination¹ without the function generator permitted measurement of one component contained in two-component mixtures without sample pretreatment, it required proper wavelength selection and could not analyze some kinds of samples. The method of two-wavelength spectrophotometric determination with the function generator herein reported has succeeded in eliminating these limitations thus permitting the analysis of many kinds of samples. This method has further made it possible to measure one component contained in three-component mixtures.     

An Improved Spectrophotometric Method for Determination of Penicillins Alone and in Pharmaceutical Dosage Forms

Abstract

A new spectrophotometric method for determining penicillins has been developed. A known volume of the penicillin solution is heated at 95[ddot]C for 70 min with ammonium molybdate, in sulphuric acid medium and the absorbance of the blue species formed is measured at 670 nm. The method has been successfully applied for the determination of thirteen commercially available penicillins. Beer's law is valid for up to 35-90 μg/ml of antibiotic (according to the penicillin). The procedure has been used for analysing some pharmaceutical preparations for these drugs, e.g., injections and capsules. The sensitivity of the method is largely increased with respect to the vanadate method previously described.     

Resolution of Ternary and Quaternary Mixtures of Drugs in Pharmaceutical Preparations by Use of Spectrophotometric Data in Conjunction with PLS-1 and PLS-2 Data Processing Methods

Abstract

Two variants of partial least-squares methodology (PLS-1 and PLS-2) have been used for the analysis of ternary and quaternary mixtures of acetaminophen-acetylsalicylic acid-codeine and caffeine, respectively. This methodology permits the simultaneous quantification of the aforementioned drugs even with closely overlapping spectral bands without any separation step. The concentration ranges are 4.0–12.0, 0.2–1.0 and 4.0–12.0 μg·ml^?1 for acetaminophen-acetylsalicylic acid-codeine and 10.0–20.0, 6.0–16.0, 1.0–5.0 and 0.2–1.0 μg·ml^?1 for acetaminophen-acetylsalicylic acid-caffeine and codeine, respectively. A systematic study of the experimental data by applying an exhaustive statistical analysis to demostrate the validity of the proposed methods is presented. The results of the determination of these drugs in pharmaceutical preparations are also presented. The analytical results were quite good in all cases.     

Determination of Pentaerythritol Tetranitrate in Pharmaceuticals by High Performance Liquid Chromatography

Abstract

A high performance liquid chromatographic procedure for the analysis of pharmaceutical formulations containing pentaerythritol tetranitrate including the diluted bulk drug and finished products consisting of uncoated tablets and timed-release capsules and tablets was developed. The method employs a reversed-phase system with UV detection at 230 nm. Replicate analyses of 11 commercial formulations (5 diluted bulk drugs and 6 dosage forms gave precision values (CV) having a range of 0.17 to 1.80%. Recovery values obtained from these commercial preparations via fortification ranged from 98.8 to 102.0% while recoveries from 3 synthetic mixtures varied from 99.2 to 100.8%. The detector response for the analyte was observed to be linear over a 50-fold concentration range using nitroglycerin as the internal standard. The proposed HPLC method is specific, easy to perform and exhibits excellent accuracy and precision. Seven different brands of HPLC columns were evaluated for possible use with the method.     

Simultaneous Spectrophotometric Determination of Levodopa and Benserazide in a Pharmaceutical

ABSTRACT

A method based on a partial least-squares calibration (PLS) for the simultaneous spectrophotometric determination of levodopa (I) and benserazide (II) in a commercially available pharmaceutical preparation is proposed. The calibration procedure was developped by using laboratory made mixtures of I and II, and optimized by selecting the most suitable wavelength range and spectral mode. The relative standard error of prediction (RSEP %) was 0.5% and 0.9% with a limiting reproducibility (R) of 4 10^?6 M and 1.5 10^?6 M for levodopa and benserazide, respectively The proposed method is straightforward, expeditious and precise. Its results are consistent with those provided by HPLC for the two analytes.     

Simultaneous Determination of Lonidamine, 1-(2,4-Dichlorobenzyl)-1h-indazole-3-carboxylic Acid,a New Antitumoral,and Its Impurity,N2 Substituted Isomer,by UV Derivative Spectrophotometry

Abstract

A direct and fast analytical method for the determination of Lonidamine and its impurity of synthesis, the N₂ alkylated isomer, by UV derivative spectrophotometry, is described.

The procedure was defined by regression analysis for a high number of standard solutions.

Linear relationships were obtained between mixture composition and maximum amplitude in <²D at 316 nm for Lonidamine quantitation, and peak trough ⁴D 226,234 and ⁴D 323,316 amplitudes by utilising polynomial equation for N₂ isomer quantitation.

The method, yielding accurate and precise results, was satisfactorily applied to laboratory mixtures and to a commercial formulation.     

Rapid and Accurate Determination of Acetaminophen and Phenprobamate in Binary Mixtures by Derivative-Differential UV Spectrophotometry and Ratio-Spectra Derivative Spectrophotometry

ABSTRACT

Derivative-Differential UV spectrophotometry and ratio-spectra first derivative spectrophotometry are presented for the simultaneous determination of analgesic and myorelaxan mixtures, namely acetaminophen (A)- phenprobamate (P). Derivative-Differential UV spectrophotometry is based on pH changes. The other method depends on the application ratio-spectra first derivative spectrophotometry to resolve the interference due to spectral overlapping.

The proposed methods were applied to the determination of this compound in synthetic mixtures and in pharmaceutical preparations. The proposed methods, which give thoroughly comparable data, are simple and rapid, and allow one to obtain precise and accurate results.     

Influence of the Selected Wavelength Range on the Simultaneous Spectrophotometric Determination of Mixture Components by Use of Partial Least-Squares Regression

ABSTRACT

This paper shows the benefits of optimizing the wavelength range and number of factors used in the simultaneous spectrophotometric determination of several analytes in the same sample by use of partial least-squares regression. The optimization criterion used for this purpose is based on the relative standard error of prediction (RSEP), which represents the overall error for a series of mixtures containing different amounts of the analytes; the optimum wavelength range and number of factors are chosen to be those leading to the lowest RSEP value. The ensuing method was applied to the simultaneous determination of the diuretics spironolactone and althiazide at concentrations between 2 and 20 μg · mL^?1 in synthetic samples, where the drugs were quantified with errors less than 5% (spironolactone) and 2.5% (althiazide), and relative standard deviations below 3.5 and 0.8%, respectively. Both drugs were also determined in a pharmaceutical preparation, with recoveries of 100.76% (spironolactone) and 95.86% (althiazide) relative to their nominal contents, and relative standard deviations of 1.1 and 3.5%, respectively. The proposed method for the analysis of the pharmaceutical preparation was validated by HPLC.