A Sensitive Spectrophotometric Method for the Determination of Progesterone,Testosterone Propionate and Nandrolone Phenylpropionate in Ampoules

Abstract

A sensitive spectrophotometric method for the determination of three kdetosteriod drugs is suggested. The method is based on oximation, separation and acid cleavage of their oximes followed by spectro-photometric measurement of the liberated hydroxylamine through oxidation and diazo coupling reactions. The method gave mean percent recoveries of 98.92 ± 0.58, 99.26 ± 0.96, and 99 10 ± 0.47 for progesterone, testosterone propionate and nandrolone phenyl propionate respectively in ampoules. Results were in good agreement with B.P. 1980 method.     

Kinetic Spectrophotometric Determination of Manganese by Use of the Salicylaldehyde-Hydrogen Peroxide System

Abstract

A kinetic method is described for determining trace amounts of manganese(II), based on its catalytic effect on the oxidation of salicylaldehyde by hydrogen peroxide. The reaction is followed spectrophotometrically by measuring the rate of change of absorbance at 500 nm. The calibration graph is linear in the range 5–100 ng/ml with a relative error of ± 1.2%. The method has been applied to the determination of manganese in natural water.     

Determination of Ephedrine via the Formation of Metal Complexes

Abstract

The reaction of ephedrine with carbon disulphide and metals'reagents (nickel, copper and cobalt has been studied. Various methods are accordingly introduced for the determination of ephedrine in pure form and in pharmaceutical formulations. Direct spectrophotometric method determines 0.24-1.21, 0.61-5.45 and 6.05-60.5 μ moles. of epherdrine with a mean accuracy (P'=0.05) of 100.24± 1.48%,99.65±1.68% and 99.73±0.59% using nickel, copper and cobalt respectively. Indirect determinations- through the metals' content- include atomic absorption method, which is suitable for the determination of 0.73-8.5, 1.82-6.66 and 3.63-24.2 μ moles. of ephedrine with a mean accuracy of 99.49±1.18%, 100.13±1.65% and 99.68±0.63% on using nickel, copper and cobalt respectively. The corresponding data on determining the metals by the oxalyldrazide method are : 1.45-16.94, 0.61-1.57 and 0.73-17.54 μ moles. of epherdrine, 99.13±0.6%, 99.35±0.71% and 99.54±0.73% on using nickel, copper and cobalt respectively.     

Flow Injection Analysis Determination of Ascorbic Acid with Spectrofluorimetric Detection

Abstract

A flow injection system for the fluorescence determination of low level of ascorbic acid is proposed. The method is based on the rapid oxidation of ascorbic acid by thallium(I). The fluorescence signal at 419 nm is proportional to the amount of ascorbic acid in the range of (1.4–28.0) × 10^?7 mole. The relative standard deviations for ten replicate measurements of 1.4 × 10^?6 mole of ascorbic acid was 1.3%. The sample rate of 45 ± 5 sample per hour was achieved. The usefulness of the method was tested in the determination of ascorbic acid in fruit juices and vitamin C tablets.     

Spectrophotometric Determination of Steroid Oximes

Abstract

A spectrophotometric procedure for the determination of steroid oximes is described utilizing 11β-hydroxy-iia-methyl-5β-pregnane -3, 20 -dione dioxime (I) and iia-hydroxy-progesterone dioxime (II) as models. The method is based on (a) acid hydrolysis to release hydroxylamine, (b) oxidation of hydroxylamine to nitrous acid with iodine, (c) diazotization of sulfanilic acid with the nitrous acid, (d) coupling of the diazonium compound with N-(i-naphthyl)-ethylenediamine dihydrochloride, and (e) measurement of the azo dye at 550 nm. A stoichiometric yield of hydroxylamine is obtained. Analyses of I and II have given typical recoveries (mean ± S. D.) of 99.5 ± 1.1% and 97.8 + 3.5%, respectively. The method is sensitive to ≥ 0.3 × 10^?5 M dioxime.     

A New Kinetic-Fluorimetric Method for the Determination of Silver Based on Its Inhibitory Effect on the Oxidation of 2-Hydroxybenzaldehyde Thiosemicarbazone with Hydrogen Peroxide Catalyzed by Iron (III)

Abstract

An indirect kinetic determination of silver based on its inhibitory effect on the oxidation of 2-hydroxybenzaldehyde thiosemicarbazone with hydrogen peroxide catalyzed by iron (III) is described. The reaction is followed spectrofluorimetrically by measurement of the initial rate at the wavelengths of the oxidation product (λ_exc=365nm, λ_em=440nm.). The calibration curves are linear between 50-400 ng.ml^?1 of silver with a precision of ± 2.3%. The proposed method has few interferences.     

Gas-Liquid Chromatographic Determination of Diphenhydramine (Dimedrol) Hydrochloride in Some Pharmaceutical Formulations

Abstract

A rapid quantitative gas-liquid chromatographic procedure for the determination of 2-diphenylmethoxy-N, N-dimethylethanamine (diphenhydramine, dimedrol) hydrochloride, in pure form and when it is dispensed in eye drops and lotion, is described. The antihistaminic drug requires no conversion to the free base, and the assayed pharmaceutical formulations need no sample cleanup, preliminary drug separation or derivatization. The method is adopted for a concentration range varied between1.0 - 10 mg.ml^?1 of the drug in ethanolic solutions. The accuracy obtained was 98.6 ± 0.31%, 93.3 ± 0.82%, and 87.9 ± 1.1% for the authentic diphenhydramine hydrochloride, its eye drops and its lotion. The 50% - addition of the drug to the labelled claim in the galenical forms, eye drops and lotion, gives average mean recoveries of 100.8 ± 0.74% and 97.9 ± 0.45% respectively.     

Synthesis of Dimedone-Annelated Heterocycles: Regioselective Heterocyclization of 2-(Cyclohex-2′-enyl)-5,5-dimethyl-3-hydroxy cyclohex-2-enone

Abstract

2-(Cyclohex-2′-enyl)-5,5-dimethyl-3-hydroxycyclohex-2-enone undergoes regioselective heterocyclization to give bridged heterocycles 5a,b and 7 on treatment with pyridine hydrotribromide or hexamethylenetetramine hydrotribromide (1 h); or elemental bromine (7 h); N-iodosuccinimide in acetonitrile at 0–5°C (1 h) and conc. H₂SO₄ at 0–5°C (2 h), respectively.     

A pH-Stat Approach to the Enzymatic Inhibition Analysis of Some Selected Serum Cholinesterase Inhibitors

Abstract

An enzymatic method is described for the pH-stat determination of a series of alkaloids, vitamins, sulfonamides and anions based on the inhibitory effect on the cholinesterase-catalyzed hydrolysis of butyrylcholine iodide (BuCh). All analyses were done at 25.0°C and pH 8.00 Creadable reproducibility of ± 0.02 pH unit)- Sensitivity ranges from 13 ng (physostigmine) to 0.86 g (niacinamide). The precision is < 2.0% with the exception of physostigmine which is ≤ 5.2%. The average recovery and analysis times were (98.1–104.1)% and 10 min., respectively. Complete Inhibition curves are presented and the relative inhibitory “potency” of the compounds examined is inferred.     

Colorimetric and Bromometric Determination of Pirbuterol Hydrochloride

Abstract

Two proposed methods are reported for the quantitation of pirbuterol hydrochloride, namely, (i) colorimetric and (ii) titrimetric methods. The colorimetric method is based on coupling betweem diazotized sulphanilamide and pirbuterol hydrochloride. Under the optimum conditions studied, the coupling product exhibits a maximum at 440 nm. Linear relation between absorbance, A, and concentration of pirbuterol hydrochloride is in the range 5–40 μgml^?1. The mean percentage obtained for capsules (Exirel^R ?15 mg) was 100.8 ± 0.7 whereas mean percentage recovery obtained for the authentic drug was 100.5 ± 0.8.

The titrimetric procedure involves bromination of authentic pirbuterol in acid medium and residual titration of excess bromine. The stoichiometry of the reaction was investigated and infra-red analysis, of the bromoderivative was carried out. When applied to capsules the bromometric method gave mean percentage of 100.18 ± 2.25.     

High Performance Liquid Chromatographic Determination of Pirenzepine Dihydrochloride in Its Pharmaceutical Formulation

Abstract

A high-performance liquid chromatographic procedure for the determination of pirenzepine dihydrochloride as a bulk material and in its tablet dosage form (Gastrozepin^R) is presented. Normal phase liquid chromatography has been performed on a Micro-pack Si-10 column using ammonium hydroxide (28–30% NH₃) in methanol (0.75: 99.25% v/v) as mobile phase at a flow rate of 2 ml/min. Clobazam has been used as internal standard with retention times of 1.9 and 2.8 minutes for clobazam and pirenzepine dihydrochloride, respectively at 254 nm. Analytical calibration yields a linear relationship between 5 and 25 μg/ml, with correlation coefficient of 0.999. Tablets each labelled to contain 25 mg pirenzepine dihydrochloride give mean percentage found of 99.98 ± 0.4. A plot of logarithm of concentration against time for a solution in 6 N hydrochloric acid gives a straight line with a slope of - 0.197 day^?1. The proposed method is, therefore, a stability indicating method.     

Determination of the Total Nitrogen Content of Organic Substances Through the Ammonia Formed in Oxidation by Persulfate

Abstract

A new concept for the analytical application of persulfate oxidation in alkaline media is presented: The persulfate oxidation of organic compounds has been utilized to determine their nitrogen content. The ammonia formed in the oxidation coupled distillation was measured acidimetrically with an accuracy of ± 0.5 % (rel.). The applicability of the method proposed is shown in the determination of the organically bound nitrogen content of numerous model substances as well as industrial and natural matrices: vinasse, aluminate liquor, white- and soy-bean samples, eggprotein.     

Successive Determination of Picogram Amounts of Phosphorus and Arsenic in Pure Water by Indirect Flameless Atomic Absorption (Mo) Spectroscopy

Abstract

The method involves the conversion of the P and As into the yellow 12-molybdo-phosphate or - arsenate complex, respectively, extraction into butyl acetate (in the case of As - with the preliminary addition of ethanol), the decomposition of the heteropoly-compounds with aqueous NH₃ and the back extraction of the liberated Mo into aqueous solution, for flameless AA determination. 10 pg P and 25 pg As in 0.4 ml samples of ultrapure water were determined with percentage errors below ±30%.     

Study of the Reaction of Glutathione with 2,2,6,6-Tetramethyl-4-Hydroxy Piperidine Nitroxide by RP-HPLC

Abstract

In this paper, the quantitative determination of the oxidation products from the reaction mixture of glutathione with 2,2,6,6-tetramethyl-4-hydroxy piperidine nitroxide was carried out satisfactorily by RP-HPLC with an external standard method. The relative error of the quantitative analysis was less than ± 2.0%, the standard deviation was less than 0.68 and the recovery rate was almost above 99%.     

Quantitative Bestimmung von Sulfat und Sulfid (nach Oxydation) mit Hilfe des Orion-„Ionalizers“

A potentiometric procedure for the determination of sulphate has been tested. The analysis requires approx. 10–15 min time. The determination of the end-point is free from individual influences. In the determination of 0.1 N sodium sulphate an average error of the single measurement of fm=± 0.7% was observed. The more detailed complexometric method according to ?Deutsche Einheitsverfahren“ yielded an average mistake of fm=±2%. The method was applied to the determination of sulphate from sulphide (after oxidation of the latter). No considerable deviation from the gravimetrically ascertained values was noted. Borate does not interfere.     

Stability-Indicating Method For The Determination Of N-Desmethyldiazepam And Simultaneous Determination Of Its Degradation Products

Abstract

A simple, direct and sensitive spectrophotometric method for the determination of the intact N-desmethyldiazepam in the presence of its degradation products, 2-amino-5-chlorobenzophenone and glycine, is developed. The proposed procedure is based on direct measurement of the absorbance of its acidified methanolic solution at 361 nm. The procedure determines 8–56 mcg ml^?1 of N-desmethyldiazepam with an accuracy of 100.2 ± 0.51%. The proposed procedure retains its accuracy in presence of up to 80% of the different degradation products. The procedure is applied successfully for the determination of N-desmethyldiazepam in bulk powder, tablets and drops.

Simultaneous determination of the different degradation products in the presence of the parent drug is also described. Thus, 2-amino-5-chlorobenzophenone is determined by direct measurement of its methanolic solution at about 380 nm, with an accuracy of 100.4 ± 0.42%. Glycine is determined colorimetrically using ninhydrin reagent in presence of pyridine, with an accuracy of 99.5 ± 0.78%.     

Spectrophotometric Determination of Risedronate and Etidronate in Pharmaceutical Formulations via the Molybdovanadate Method

Abstract

An accurate and sensitive spectrophotometric method was developed for the determination of risedronate and etidronate in pharmaceuticals. The method was based on oxidation of the studied drugs with potassium persulfate and reaction of the generated orthophosphate ions with molybdovanadate reagent. The produced yellow phosphovanadomolybdate complex was measured at 313 nm. The method was rectilinear in the ranges 0.5–10 and 0.5–8 µg/mL with detection limits of 0.087 and 0.122 µg/mL for risedronate and etidronate, respectively. The method was applied for the determination of the studied drugs in their tablets, and the results agreed with those obtained by the comparison methods.     

Spectrofluorometric Determination of Drotaverine Hydrochloride in Pharmaceutical Preparations

Abstract

A highly sensitive, spectrofluorometric method was developed for the determination of drotaverine HCl in pharmaceutical preparations. The proposed method is based on the measurement of the native fluorescence of the drug in 0.1 M H₂SO₄ at emission 465 nm after excitation at 295 nm. The relative fluorescence intensity-concentration plot was rectilinear over the range of 0.16–4 µg·ml^?1, with good correlation (r = 0.9999) and a lower limit of detection (LOD) of 0.032 µg·ml?1. The proposed method was successfully applied for the determination of drotaverine HCl in tablets and ampoules with a recovery percentage of 100.42 ± 0.601,99.83 ± 0.82 and 99.43 ± 1.08, respectively, which were in accordance with those obtained by a compendial method.     

Assay of Bicarbonate Content in Certain Effervescent Formulations

Abstract

A quantitative method was developed for the assay of the bicarbonate content in a number of potassium-replacement effervescent tablets with citric acid. The method involved treatment of an aliquot of the crushed tablet with water, then with 0.5 N sulfuric acid, followed by quantitative absorption of the liberated carbon dioxide into 0.2 N sodium hydroxide in a closed system with a calcium chloride-protected vent. The sodium carbonate-sodium hydroxide solution was subjected to a two-step titration with standard acid using phenolphthalein and bromophenol blue indicators for the first and second step, respectively. Overall percent recovery (± SD) of potassium bicarbonate from simulated tablets were: 99.6 ± 0.9% (n = 4); in presence of potassium citrate, 100.0 ± 1.3% (n = 4); and in presence of potassium chloride and L-lysine hydrochloride, 101.5 ± 1.9% (n = 3). Application of the method to commercial products near the expiration date showed potassium bicarbonate contents of 80–90% of label claim. The method may be applied to the assay of any bicarbonate salt in other effervescent formulations.     

Extractive Spectrqphotometric Determination of Vanadium Liith o-Aminobenzo-Hydroxamic Acid

Abstract

A new spectrophotometric method for vanadium determination is proposed. The method is based on the extraction in Adogen-toluene solution of the complex formed between V(V) and o-Aminobenzohydraxámic acid

The method allows determination of 50 to 110 μg of V(V). The error and the apparent molar absorptivity are 1.2% and 5.2 ± 10³ l.mol^?1. cm^?1 respectively. The interferences caused by foreign ions have been established. The method is applied with success to determination of vanadium in petroleum crudes.