Quantitative Densitometric Determination of Theophylline

Abstract

A method for identification and quantification of theophylline in certain dosage forms, that employs TLC-scanner is reported. the method is applied for theophylline either as raw material or in certain dosage forms admixed with other medicamenta. Samples were extracted with methanol, separated and measured in situ on silica gel G plates at about 270 nm using TLC-scanner. the mean recovery (six determinations) was 99.9± 0.57. the developed procedure has been found to be simple, rapid and precise and its application to various dosage forms was demonstrated and yields comparable results with UV measurement after location, scraping and elution from the plates.     

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.     

The Determination of Methenamine and its Salts in Tablet Dosage Forms Using Ion-Pair Extraction

Abstract

This paper reports a simple, accurate, reproducible, stability-indicating procedure which may be used to quantitatively determine methenamine base, methenamine mandelate or methenamine hippurate in tablet dosage forms. The procedure initially involves the separation of methenamine from the dosage form and from formaldehyde, the decomposition product, by a cartridge ion-pair extraction process. The methenamine may then be assayed by a number of methods. In this paper the methenamine was hydrolyzed to formaldehyde and the formaldehyde determined by the Nash procedure. The method compares favorably with the USP XXI procedure for methenamine tablets. Advantages of the procedure include the ability to use a single method for the base and salt forms of the drug and the potential application to stability and quality control studies of methenamine dosage forms.     

Spectrofluorimetric Determination of Indenolol in Biological Fluids

Abstract

A simple sensitive and highly reproducible fluorimetric method for the routine determination of indenolol in biological fluids and in dosage forms has been developed.     

High Performance Liquid Chromatographic Assay of Verapamil Hydrochloride in Dosage Formsk

Abstract

A stability indicating high-performance liquid chromatographic (HPLC) method for determining verapamil hydrochloride in dosage forms is described. The assay affords baseline separation of the drug from its synthesis impurities and from photolytic degradation products, as well as from formulation excipients. The drug was extracted in 0.05 N hydrochloric acid, chromatographed on a C₁₈ reverse-phase column, eluted with methanol-water-acetic acid-triethylamine (55:44:1:0.1) and the effluent was detected at 280 nm. Linearity studies were carried out using peak height or peak area measurements and the detector response to the concentration of verapamil hydrochloride was confirmed. Excellent interlaboratory precision and recovery data were obtained by the spiked placebo method. This procedure was rapid and selective for the assay of the cardiotonic drug. Application of the method for the assay of verapamil hydrochloride in representative dosage forms is described.     

Determination of Bretylium in Pharmaceutical Dosage Forms

Abstract

A simple, high-pressure liquid chromatographic method for determination of bretylium in pharmaceutical dosage forms is described. The sensitivity of the method is 50 ng with high reproducibility. Exogenous additives from injection, infusion or tablet dosage forms do not interfere with the assay. An increase in the pH of the sample, however, caused a decrease in the peak height of bretylium. Bretylium is a chemically stable compound. Under conditions of either 1.5 N hydrochloric acid, nitric acid, or sodium hydroxide at 25°C and 100°C for a period of up to 48 hours did not influence the outcome of the assay.     

Spectrofluorimetric determination of two β-agonist drugs in bulk and pharmaceutical dosage forms via derivatization with dansyl chloride

A sensitive, simple and rapid spectrofluorimetric method has been developed for the determination of both Fenoterol hydrobromide (FNT) and Ritodrine hydrochloride (RTH) in pure and dosage forms. The method is based on derivatization using dansyl chloride (DNS-Cl) as fluorogenic agent and measuring the fluorescence of the products at emission wavelengths of 517 and 515 nm after excitation at 348 and 343 nm for FNT and RTH, respectively. Different experimental parameters affecting the fluorescence intensities were carefully studied and optimized. The relation between fluorescence intensities and drug concentrations were rectilinear over the concentration range of 0.25–6.0 μg/mL for both drugs with a minimum detectability of 0.065 and 0.045 μg/mL for FNT and RTH, respectively. The percentage recoveries ±SD were 100.1 ± 0.9, 99.9 ± 0.6 for FNT and RTH respectively. The proposed method was successfully applied to the determination of both drugs in their commercial dosage forms. The obtained results were statistically validated and agreed well with those obtained with reference methods. A suggestion for the reaction pathway with DNS-Cl was postulated.     

HPLC-Methods for Separation and Quantitation of Reserpin and its Main Degradation Products

Abstract

An analytical method suitable for the stability control of dosage forms containing reserpine by HPLC is described. Besides reserpine the method quantitatively determines isoreserpine, 3,4-didehydroreserpine, trimethoxybenzoic acid, and renoxidine. The additional degradation products reserpic acid, and the secondary oxidation product 3,4,5,6-tetradehydroreserpine are qualitatively recorded.     

Indirect Determination of Organic Compounds by Atomic Absorption Spectrophotometry: The Study of Vitamin B12 in Pharmaceutical Dosage Forms

Abstract

A method for the determination of vitamin B₁₂ in pharmaceutical dosage forms is presented. The method involves, dissolution of the vitamin B₁₂ and subsequent determination of the complexed cobalt by atomic absorption spectrophotometry. The method is both rapid and sensitive giving applications to quality, control of this type of formulation.     

High Performance Liquid Chromatographic Analysis of Penicillin V Solid Dosage Forms

Abstract

An isocratic high performance liquid chromatographic (HPLC) method for the determination of Penicillin V in solid dosage forms is described. A reverse phase RP-8 column and a mobile phase of 52% methanol in 0.05 M phosphate buffer (pH 3.3) were employed. Detection was effected at 254 nm. The results obtained are compared with those from the iodometric method.     

High Performance Liquid Chromatographic Assay of Hydromorphone Hydrochloride Injection

Abstract

A stability indicating high performance liquid chromatographic (HPLC) method for determining hydromorphone hydrochloride in dosage forms is described. The drug was chromatographed on a C₁₈ reverse phase column, using a mobile phase consisting of sodium lauryl sulfate, acetic acid, acetonitrile and water, and detected at 280 nm. Linearity of detector response to the concentration was confirmed. The procedure showed excellent reproducibility and gave quantitative recoveries of the drug from spiked placebos. Photodegraded samples of the dosage form, were assayed by the HPLC procedure and the current USP spectrophotometric procedure. Comparison of the results showed that the USP procedure is only partially stability indicating.     

Colorimetric and Atomic Absorption Spectrometric Determination of Some Heterocyclic Nitrogenous Compounds of Pharmaceutical Interest

Abstract

Simple spectroanalytical methods are proposed for the determination of five heterocyclic nitrogenous compounds. The suggested methods depend upon the formation of the ion-pair complexes of the studied compounds with ammonium reineckate followed by colorimetric and atomic absorption measurement of the complexes solutions. The proposed methods were applied to the determination of some pharmaceutical dosage forms containing the studied compounds. Results obtained were in agreement with those obtained by official and compendium methods.     

Development and validation of RP-HPLC method for simultaneous estimation of prednicarbate,mupirocin and ketoconazole in topical dosage forms

A simple and accurate reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for simultaneous estimation of prednicarbate (PC), mupirocin (MP) and ketoconazole (KT) in topical dosage forms. This combination is preferred for topical delivery of anti-inflammatory, antibacterial and antifungal agents for treatment of various skin disorders. The proposed RP-HPLC method utilizes a Hypersil GOLD C18, 5 μm, 250 mm × 4.6 mm i.d. column, mobile phase consisting of methanol-water (80: 20, v/v) adjusted to pH 5.0 with orthophosphoric acid in isocratic mode at the flow rate of 0.5 mL/min and UV detection at 243 nm. The method does not require any specific sample preparation except extraction of active pharmaceutical ingredients from the developed topical emulgel formulations using dichloromethane. Linearity was found in the range of 0.05–0.3 mg/L for PC and 0.4–2.4 mg/L for each of MP and KT with R ² > 0.999. The method is precise with low RSD%, accurate (overall average recovery yields: 99.92% for PC, 99.44% for MP and 99.74% for KT) and selective. Due to its simplicity and accuracy, the method is suitable for simultaneous analysis of PC, MP and KT in topical dosage forms.     

GLC and Colorimetric Methods for the Determination of Capsaicin

Abstract

GLC and colorimetric methods for Capsaicin and its dosage forms are investigated. They offer an improvement in ease, speed and accuracy. The first GLC method is based on the formation of methyl derivative of capsaicin. The colorimetric procedure is based on the formation of O-nitroso-derivative between the drug and sodium nitrite.     

Quantitation of Hydralazine Hydro-Chloride in Pharmaceutical Dosage Forms Using Highc Performance Liquid Chromatography

Abstract

Stability-indicating assay methods for the quantitation of hydralazine hydrochloride based on high-performance liquid chroma-tography using two different columns have been developed. Phenyl-prooanolamine can be used as an internal standard with both columns (μC₁₈ and μphenyl) while hydrochlorothiazide can be used only with μphenyl column. The method is accurate and precise with percent relative standard deviations based on 6 readings of less than 2. The excipients present in the dosage forms did not interfere with the assay method. In combination with hydrochlorothiazide, hydralazine can be quantified only with μphenyl column. Two oral liquid dosage forms prepared in a local hospital using commercially available strawberry syrup/simple syrup decomposed completely in one day.     

Determination and Quantification of Pitavastatin Calcium in Tablet Dosage Formulation by HPTLC Method

Abstract

A simple, sensitive, reliable, and rapid HPTLC method has been developed for the determination of pitavastatin calcium in tablet dosage form. Identification and determination were performed on aluminum backed silica gel 60F₂₅₄ washed with methanol. The mobile phase of ethyl acetate‐methanol‐ammonia‐1 drop formic acid (7:2:0.8) calibration plots were established showing the dependence of response (peak area) on the amount chromatographed. The spot were scanned at 245 nm. The method has a linear range of 50–250 ng/spot. The method was validated for selectivity, repeatability, and accuracy. The method was used for determination of the compound in commercial pharmaceutical dosage forms. It is a more effective option than other chromatographic techniques in routine quality control.     

Liquid Chromatographic Assay for Salicylic Acid in Liquid and Semisolid Formulations

Abstract

A high performance liquid chromatographic assay for quantitating salicylic acid (S) in lotion, collodion, ointment and cream formulations is described. The method involved direct determination of S in the liquid dosage forms after appropriate dilutions with the mobile phase. Prior extraction of S from ointments and creams was carried by chloroform. Metronidazole was used as the internal standard and a μ-Bondapak phenyl column with a mobile phase made of 30%, methanol in 5 mM solution of tetrabutylammonium phosphate (pH 7.5) led to an efficient separation. Retention times of about 3 and 7.5 min were obtained for the internal standard and S respectively. The recovery of S from the dosage forms was tested by adding known amounts of S to each preparation and mixing before determination. The mean percentage recovery was in the range of 98–101.1%. The method was found to be accurate, simple and reproducible.     

Application of the ‘Zero-Crossing’ Derivative Spectrophotometry to the Analysis of Mixtures of Cefoperazone and Cefamandole Nafate in Pure and Pharmaceutical Dosage Forms

Abstract

‘Zero - crossing’ first and second derivative spectrophotometry has been employed for the quantitation of mixtures of cefoperazone Na and cefamandole nafate. Beer's law holds for up to 44 ug/ml of each cephalosporin, in both derivative modes. The method has been applied to the recovery of these antibiotics in mixtures of injectable dosage forms.     

Electroanalytical Application of Carbon Based Electrodes to the Pharmaceuticals

Abstract

Carbon and its derivatives, as the high performance material, occupy a special place in electrochemistry due to its ‐in many ways‐ extreme properties. Recent trends and advances in the electrochemistry of carbon‐based electrodes are reviewed. The varieties of carbon‐based electrodes, their basic physicochemical properties and some characteristics are surveyed. Special attention is paid to the possibilities of carbon‐based electrodes in electroanalytical investigation in pharmaceutical dosage forms and biological samples using modern electrochemical techniques. This review includes a summary of the rules that must be considered for drug analysis from its dosage forms and biological samples using carbon‐based electrodes. The present review is the first comprehensive report on the heterogeneous and homogeneous carbon electrodes, and an addition to many excellent reviews on carbon electrodes in the literature. This review summarizes some of the recent developments and applications of carbon‐based electrodes for drug compounds in their dosage forms and in biological samples in the period from 1996 till 2006. Also some further selected designs (screen‐printed; carbon nanotubes, etc.) and applications have been discussed.     

Spectrophotometric Determination of Chlorpheniramine in Some Dosage Forms Using the Charge – Transfer Complexation Technique

SUMMARY

A spectrophotometric method of assay of chlorpheniramine in some of its dosage forms based on the principle of charge transfer complexation between chlorpheniramine (the n – donor) and chloranilic acid (the π - acceptor) is described.

A 1:1 molecular complex with maximum absorption at 530 nm was formed. The association constant, molar absorptivity, and free energy change of the complex indicate that the complex has high stability. Beer's law was obeyed within the concentration range of 2 to 24 mg% (0.2 to 0.24 mg/ml.). The sensitivity of this method is 4.02 x 10^?5M of chlorpheniramine base. There were high percentage recoveries when the method was employed to the quantitative determination of chlorpheniramine from commercial tablets and injection. This newly proposed method is easy, fast and requires minimum chemicals and equipment, and, therefore, could be utilized in the assay of chlorpheniramine in dosage forms.