First Derivative Spectrophotometric Determination of Certain Drugs in Two-Component Mixtures

Abstract

Four two-component mixtures have been assayed using both Vierordt's and first derivative spectrophotometric methods. Such mixtures are acepifylline and phenobarbitone, phenylbutazone and amidopyrine, procaine and caffeine, and sulphamethoxazole and trimethoprim. These selected applications illustrate the relative ease and simplicity offered by first derivative spectrophotometry for the assay of two component mixtures with spectral interferences from matrix formulations.     

导数吸附伏安法同时测定柠檬黄及日落黄

色素日落黄和柠檬黄在ｐＨ８．２的硼酸钠－酸介质中均有良好的吸附伏安波，但波峰相互重叠，难以同时测定。本文提出以二阶导数法对日落黄和柠檬黄的重叠伏安波谱进行分析，以达到日落黄和柠檬黄同时测定的目的，方法简便快速。本法分析几种饮料中的日落黄及柠檬黄，结果满意。     

Spectrophotometric Determination of Cefadroxil and Metyrosine in Dosage Forms

Abstract

A simple and sensitive spectrophotometric method is described for the determination of cefadroxil and metyrosine in pure form and in pharmaceutical formulations. The method is based on reacting these drugs with 4-aminoantipyrine (AAP) in the presence of an alkaline oxidising agent. The coloured products were measured spectrophotometrically at 500 nm and 470 nm for cefadroxil and metyrosine, respectively. Beer's law was obeyed over the concentration range 1-28 and 2-44 μg ml^-1 for cefadroxil monohydrate and metyrosine, respectively. The molar ratio in both cases was established and a proposal for the reaction pathway was suggested. The percentage recoveries obtained were in accordance with those given by the reference methods.     

Ratio-Spectra Zero-Crossing Derivative Spectrophotometric Determination of Certain Drugs in Two-Component Mixtures

ABSTRACT

Two two-component mixtures have been assayed using both Vierordt's method and ratio-spectra zero-crossing derivative spectrophotometric methods. Such mixtures are hydrochlorothiazide-spironolactone and hydrochlorothiazide-ramipril. These selected applications illustrate the relative ease and simplicity offered by ratio - spectra zero - crossing derivative spectrophotometry for the assay of two component mixtures with spectral interferences from matrix formulations.     

The Use of Charge Transfer Complexation in the Spectrophotometric Determination of Some Corticosteroid Drugs Through Intermediate Oxime Formation

Abstract

Two spectrophotometric procedures for the assay of three corticosteroid drugs through oximation and subsequent charge transfer complexation with two electron acceptor substances are proposed. The optimum experimental conditions, and molar ratio of reactants were studied. The applicability of the proposed procedures to assay the tested compounds in tablets from and comparison with an official method revealed the reliability, sensitivity and accuracy of the suggested procedures.     

Spectrophotometric Determination of Some Antibacterial Drugs Using p-Nitrophenol

Abstract

A simple, quick and sensitive spectrophotometric method for pipemidic acid, norfloxacin and ciprofloxacin lactate is described, based on a reaction with p-nitrophenol in water medium, apparently by a charge-transfer mechanism, to yield 1:1 complexes with analytically useful maximum absorption at 404 nm, 407nm and 403nm. Optimum conditions for determination, linear calibration range and apparent molar absorptivities have been reported. The methods are highly accurate and have been successfully applied to the determination of pipemidic acid, norfloxacin and ciprofloxacin lactate in tablets. The results are in good agreement with the official methods.     

Titrimetric and Spectrophotometric Determination of Some Phenothiazine Psychotropics in Pure Form and in Pharmaceutical Formulations with Metavanadate

 Two simple, fast, accurate and precise methods for the determination of six phenothiazines and a number of their pharmaceutical formulations are described. The titrimetric method involves the oxidation of the drugs by metavanadate in sulphuric acid medium and titration of vanadium(IV) formed, with cerium(IV) using ferroin indicator and acetone as catalyst. In spectrophotometry, vanadium(IV) formed was reacted with ferriin and the resulting ferroin measured at 510 nm. Phenothiazines in the ranges 5–100 mg and 2.5–25.0 μg mL⁻¹ can be determined by titrimetry and spectrophotometry, respectively, with detection limits of 0.96–2.05 mg and 0.0359–0.0565 μg mL⁻¹, respectively. Both methods were applied successfully to the determination of the studied drugs in pharmaceutical preparations. The reliability of the assays was established by parallel determination by the official methods of British Pharmacopoeia and the results being statistically evaluated. Received September 26, 2000. Revision March 25, 2001.     

Spectrophotometric method for assay of penicillins

Ninhydrin in 0.2M citrate buffer (pH 5) containing SnCl₂ is proposed as a new reagent for Spectrophotometric determination of penicillins and analysis of their pharmaceutical formulations. The method is based on acid hydrolysis of penicillins with 5M HCl and subsequent treatment with ninhydrin. The resulting violet colour exhibits maximum absorption at 570 nm.     

Spectrophotometric Determination of Some Cardiovascular Drugs Using P-Chloranilic Acid

Abstract

A simple and sensitive spectrophotometric method for the assay of some cardio-vascular drugs is described. The method is based on the interaction of the drug and p-chloranilic acid (p-CA) to give a stable and intensively coloured ion-pair salt. The drugs used are quinidine sulphate, prenylamine lactate, dipyridamol, hydralazine hydrochloride, tolazoline hydrochloride and pindolol. The optimum experimental conditions for colour development have been studied. Conformity to Beer's law enabled the determination of these drugs in their pharmaceutical preparations. The assay results are in accord with the pharmacopoeal assay results.     

Simultaneous Determination of Acetaminophen and Phenobarbital in Suppositories by Partial Least-Squares Spectrophotometric Calibration

Abstract

The use of partial least-squares spectrophotometric calibration for the simultaneous determination of suppositories in a multicomponent formulation is presented. This method is applied to the deternination of acetaminophen and phenobarbital in suppository preparations. The results show that these components in a molar ratio of about 61:1 in suppositories have been determined simultaneously with high precision.     

Spectrophotometric Determination of Some Phenolic Antibiotics in Dosage Forms

 A simple and sensitive spectrophotometric method is described for the determination of some phenolic antibiotics namely: cefadroxil, amoxicillin and vancomycin. The method is based on the measurement of the orange yellow species produced when the drugs are coupled with diazotized benzocaine in triethylamine medium. The method is applicable over the range of 0.8–12 μg/ml for cefadroxil, 2–16 μg/ml for amoxicillin and 2–18 μg/ml for vancomycin. The formed compounds absorb at 455 nm for both cefadroxil and amoxicillin and at 442 nm for vancomycin. The proposed method has detection limits of 0.018 μg for cefadroxil, 0.0034 μg for amoxicillin and 0.0156 μg for vancomycin. The stoichiometric ratio for the studied compounds was found to be 1:1 and a proposal of the reaction pathway was made. The proposed method was applied for the analysis of the cited drugs in their pharmaceutical preparations. The results are in good agreement with those obtained by the official methods. Received February 7, 2000. Revision June 14, 2000.     

Spectrophotometric Analysis of some Phenothiazine Neuroleptics using Chloramine-T

ABSTRACT

A sensitive and selective spectrophotometric method has been developed for the determination of six phenothiazine neuroleptics. The method is based on the interaction of the drugs with chloramine-T in sulphuric acid medium to yield a red, reddish-violet, orange or greenish-blue intermediate with maximum absorption at 500-636 nm. Beer's law is obeyed over the range 5-125 μg ml^?1 of the drugs. The apparent molar absorptivities were found to be in the range 1.04x10³ to 5.46x10³ 1.mol^?1cm^?1. The investigated drugs were assayed in tablets and injections. The mean percentage recoveries were 97.65-101.75 and the relative standard deviations were found to be less than 2%.     

Global Forcing Number of Benzenoid Graphs

A global forcing set in a simple connected graph G with a perfect matching is any subset S of E(G) such that the restriction of the characteristic function of perfect matchings of G on S is an injection. The number of edges in a global forcing set of the smallest cardinality is called the global forcing number of G. In this paper we prove several results concerning global forcing sets and numbers of benzenoid graphs. In particular, we prove that all catacondensed benzenoids and catafused coronoids with n hexagons have the global forcing number equal to n, and that for pericondensed benzenoids the global forcing number is always strictly smaller than the number of hexagons.     

A Method of Computing the PI Index of Benzenoid Hydrocarbons Using Orthogonal Cuts

The Padmakar–Ivan (PI) index of a graph G is defined as PI , where for edge e=(u,v) are the number of edges of G lying closer to u than v, and is the number of edges of G lying closer to v than u and summation goes over all edges of G. The PI index is a Wiener–Szeged-like topological index developed very recently. In this paper, we describe a method of computing PI index of benzenoid hydrocarbons (H) using orthogonal cuts. The method requires the finding of number of edges in the orthogonal cuts in a benzenoid system (H) and the edge number of H – a task significantly simpler than the calculation of PI index directly from its definition. On the eve of 70th anniversary of both Prof. Padmakar V. Khadikar and his wife Mrs. Kusum Khadikar.     

Determination of Some Quinone Containing Drugs by Direct and Titrimetric First Derivative Spectrophotometric Methods

Abstract

The first-derivative spectra of some metal complexes of danthron and phanquone show well defined, prominent peaks. This can be made the basis of a spectrophotometric technique for the determination of both danthron and phanquone.

Two spectrophotometric. procedures are described. The first-derivative spectrophotometric technique, found to be more sensitive than the direct-absorbance method when the metal complex is weakly absorbing, can be applied to the determination of danthron, and phanquone both in pure form and in pharmaceutical formulations. Danthron can be determined in the range of 0.48–5.7 mg using metal complexes. Phanquone can be determined in the range of 0.42–2.08 mg using iron (II), and 3.78–11.34 mg using cobalt (II).

The second procedure is a first-derivative spectrophotometry titration for the determination of 0.096–0.57 mg of danthron and 0.048–1.0 mg of phanquone using the standard metal ion- solutions as titrants.     

Charge-Transfer Complexation for Spectrophotometric Assay of Certain Imidazole Antifungal Drugs

Abstract

A spectrophotometric method is described for the assay of some antifungal agents containing an imidazole ring: clotrimazole, econazole, ketoconazole and miconazole. The method is based on the formation of a charge-transfer complex between the drug as n-electron donor and iodine as [sgrave]-acceptor. The product exhibited two absorption maxima at 290 and 377 nm; measurements are made at 290 nm. Beer's law is obeyed in a concentration range of 1-40 μg/ml. The method is rapid, simple and sensitive and can be applied to the analysis of some commercial dosage forms without interference. A detailed investigation of the formed complex was made with respect to its composition, association constant and free energy change.

     

Fourth Order Derivative Spectrophotometric Determination of Benzyl Alcohol in Piroxicam Injections

Piroxicam is a drug with analgesic and anti‐inflammatory properties. It is present in numerous pharmaceutical preparations. Injectable forms usually contain benzyl alcohol as an excipient, which is used as a blocking anesthetic (4%) and an antiseptic (4–10%). In this work, spectrophotometric methodology was used in order to determine benzyl alcohol in piroxicam injectable formulations by applying the fourth derivative method adopting the zero‐crossing technique. The results obtained show that the method has significant advantages over other reported methods and is appropriate for routine pharmaceutical analysis. The method showed excellent linearity in the range of 2–100 μg mL^?1 with limit of detection (S/N = 3) 0.07 μg mL^?1 (6.47 × 10^?7 M). The proposed method could be applied successfully for the determination of benzyl alcohol in injectable formulations with average % recovery of 100 ± 0.61.     

Spectrophotometric Determination of Ceftazidime in Pharmaceutical Preparations Using Neocuproin as a Complexing Agent

Abstract

A simple and reproducible spectrophotometric method for the assay of ceftazidime with neocuproin-copper(II) reagent has been developed. The procedure is based on the drug in an acidic medium, subsequent formation of yellow ternary complex in citrate buffer solution (pH 4.2), and measurement at 454 nm. Beer's law is obeyed in the range 15.0–40.0 µg mL^?1 with correlation coefficient r ² = 0.9995. The procedure holds good accuracy and precision when applied to the analysis of ceftazidime in powder for injection with good recovery percent ranging from 100.17±1.0 without interference from additives.     

Spectrophotometric Determination of Some Pharmaceutical Compounds Using 2,2-Diphenyl-1-picrylhydrazyl

Abstract

A spectrophotometric method for the determination of some pharmaceutical amides, hydrazides and thiols is described. The method is based on the reaction of the studied drugs with 2,2-diphenyl-1-picryl hydrazyl (DPPH). The latter is employed to abstract a hydrogen atom from the drugs thereby promoting a process of radical coupling. This results in a reduction of the violet colour of DPPH with the formation of the yellow coloured 2,2-diphenyl-1-picrylhydrazine (DPPH₂). This fading in colour of DPPH reagent depends on the concentration of the drug being determined. Beer's law is obeyed in the ranges of 1–5 μg/ml (for isocarboxazid and gliclazide), 0.25–2.5 μg/ml (for isoniazid), 0.5–5 μg/ml (for iproniazid), 1–7 μg/ml (for tolazamide), 2–15 μg/ml (for captopril) and 1–6 μg/ml (for sulphathiourea). The validity of the method was tested by analysing the studied drugs in pure form as well as in tablets. Results of analyses were compared statistically with the official or reported methods.     

Spectrophotometric Determination of Some Antiulcerative Drugs in Pharmaceutical Dosages

The aim of this work is to develop cheap, safe, rapid, reliable and reproducible spectrophotometric method for the assay of some antiulcerative drugs namely Omedar, Nadine and Rantag in their pharmaceutical dosages, using methyl red (MR) as a chromogenic reagent. The proposed method is based on the reaction of each of the three drugs with MR at pH 3.0. The optimum analytical variables have been investigated carefully. The maximum absorbance was obtained at 405 nm with absorptivity of 1.35 × 10⁴ L/mol cm. Beer’s law is obeyed in the range of concentration of 0.5–15 μg/mL for ranitidine (active ingredient) content in the studied drugs. The limits of detection and quantification of the drug active ingredient were 0.05 and 0.13 μg/mL, respectively, with a linear regression correlation coefficient of 0.998, and recovery was in the range 99.91–100.48%. Effects of pH, temperature, standing time and MR concentration on the determination of ranitidine hydrochloride of the drugs have been examined. This method is simple and can be used for the determination of ranitidine in the pharmaceutical dosages of antiulcerative drugs.