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.     

Colorimetric Microdetermination of some Corticosteroid Drugs Using Indophenol as Chromophoric Reagent

Abstract

A simple, rapid and sensitive method for the determination of betamethasone (I), dexamethasone (II) and hydrocortisone (III), either in the pure form or in pharmaceutical formulations is described. The method is based on the development of a brown product with indophenoi in basic aqueous-ethanolic (50% v/v) medium. The optimum reaction conditions for the charge transfer complex formed were assessed. The absorbance measurements were made at 820, 816 and 822 nm for I, II and III respectively. The calibration graph was linear in the range 1-26, 1-32 and 1-35 μg/ml of I, II and III with slopes of 0.028, 0.021 and 0.024, respectively. For more accurate analysis, Ringbom optimum concentration ranges were 2.5-23.0, 3.0-28.5 and 3.0-33.0 μg/ml for I, II and III, respectively. The precision of the procedure was checked by calculating the relative standard deviation of ten replicate determinations on a sample containing 20 μg/ml for each drug and was found to be 1.67, 1.39 and 1.85% for I, II and III, respectively. Many common excepience and common drugs present in their dosage forms do not interfere, and the tolerable levels were evaluated. Results of analysis of pure drugs and their dosage forms by the proposed method are in good agreement with those of the British Pharmacopoeia 1993 procedure.     

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.     

Kinetic Spectrophotometric Determination of Acetaldehyde

ABSTRACT

A method for determination of trace quantities of acetaldehyde based on its inhibition effect on the malachite green-sulfite reaction is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance at 613 nm by a fixed time method of 60 seconds. The method allows the determination of acetaldehyde in the range of 0.2-10 μg/ml. The limit of detection was 0.1 μg/ml and the relative standard deviation for ten determinations of 2 μg/ml acetaldehyde was 1.8%. The method is applied to the determination of acetaldehyde in chemical industrial waste water with satisfactory results.     

Fluorigenic Derivatization of Oxazepam. Application to Its Determination in Pharmaceuticals

Abstract

Oxazepam, when heated in mixtures of acetic acid and methanol, undergoes a reaction giving an intense fluorescence at excitation and emission wavelengths of 364 and 469 nm, respectively. The best reaction conditions were a 7:25 methanol:acetic acid volume ratio, a temperature of 100 °C (examinated range 50–100 °C), and a reaction time of 5 minutes. A linear range from 0.025 to 50 μg/ml with a limit of detection of 0.014 μg/ml and a reproducibility within day of less than 5% were attained. A Flow Injection Analysis method was designed and a linear range from 0.1 to 100 μg/ml with a limit of detection of 0.035 μg/ml and a reproducibility within day of less than 5% were obtained. These methods were applied to the determination of oxazepam in five pharmaceutical formulations.     

Simultaneous Determination of Micro Bromide and Iodide by Kinetic Spectrophotometric Method

ABSTRACT

ABSTRACTA new kinetic spectrophotometric method for the simultaneous determination of concentrations of micro bromide and iodide has been proposed. It is based on their catalytic effects on the reaction of m-cresol purple oxidized by potassium periodate in hydrochloride acid medium. The reaction rate was monitored by measuring the decrease in absorbance at 528nm and the increase in absorbance at 455nm. The total difference in absorbance of the sum of bromide and iodide is identical with determination of bromide was carried out after Cr(VI) oxidized I? to I₂, and I₂ was removed by extraction with CCI₄, and the amount of iodide was measured by subtracting the absorbance change of bromide from the total absorbance change in the presence of bromine and iodide. The optimum conditions influencing the reaction rate were studied. The linear range of determination is 0～4.0μg/ml for Br? and 0～3.0 μg/ml for I?. The detection limits are 0.032μg/ml for Br? and 0.059 μ/ml for I?. The method was successfully applied to the determination of micro amounts of bromide and iodide in food and life samples.     

Fluorimetric Determination of Plasma Cortisol in Chronic Renal Failure

Abstract

A fluorimetric method for the determination of plasma cortisol has been studied in detail. The method is based upon reaction with ethanol-sulphuric acid reagent and measurement of the produced fluorescence at exc. 470 and em. 550 nm. Some modifications were suggested regarding extraction solvent and time of the reaction. Under the proposed conditions, the method is rapid and a sensitivity of 1.5 μg/100 ml was attained. It was applied on 29 patients with chronic renal failure and 12 normal subjects. Cortisol levels at 8 AM in patients on either haemodialysis (27.05 ± 8.94 μg/100 ml) or under conservative treatment (45.13 ± 10.68 μg/100 ml) were significantly higher (P < 0.001) than control group (16.12 ± 3.45 μg/100 ml).     

Spectrophotometric Determination of Trimethoprim in Pure Form and in Pharmaceutical Preparations using Bromothymol Blue,Bromocresol Green and Alizarin Red S

ABSTRACT

Simple, sensitive and selective methods for the determination of trimethoprim (TMP) in pure form and in pharmaceutical formulations are described. The methods are based on the reaction of TMP as a π-electron donor with bromothymol blue (BTB), bromocresol green (BCG) and alizarin red S (ARS) as electron acceptors. The coloured products are quantified spectrophotometrically at their corresponding λ_max.

Beer's law is obeyed in case of BTB in the range 2.9-23.2 μg/ml (CHCl₃), 2.9-20.0 μg/ml (CH₂Cl₂) and 5.0-29.0 μg/ml (ClC₆H₅), in the case of BCG 2.9-27.5 μg/ml (H₂O/alc.), 2.9-18.3 μg/ml (CHCl₃) and 2.9-20.3 μg/ml (CH₂Cl₂) and for ARS in the range 3.0-12.0 μg/ml in H₂O/alc medium.

The specific absorptivities, molar absorptivities, Sandell sensitivities, standard deviations and percent recoveries are evaluated. Application of the suggested methods to dosage forms is presented and compared with the pharmacopoeial method. The interference from additives and sulfa compounds, especially sulfamethoxazole, has been overcome by extraction into chloroform or methylene chloride.     

Detection and Spectrophotometric Determination of Uranyl Ion with Erichromcyanine R

Abstract

Colour reaction has been studied for the identification and the spectrophotometric determination of uranyl ion with Erichromcyanine R. The detection limit was 7 μg. Beers law is obeyed in the concentration range containing 13 μg to 125 μg/10 ml of uranium.     

A Novel Protein Assay With an Azo Dye Using Rayleigh Light Scattering Technioque

ABSTRACT

The interaction of SPADNS [3-(4-sulfophenylazo)-4, 5-dihydroxy-2, 7-naphthalene disulfonic acid] with proteins in acidic solution was studied by spectrophotometric and Rayleigh light scattering (RLS) methods. SPADNS reacts rapidly with albumin at room temperature, and the intensity of the weak RLS of SPADNS was enhanced remarkably and quantitatively by this reaction.

Based on this observation, a novel RLS method for serum albumin determination was developed. The linear range is 0.125-14.9 μg/ml for BSA. The relative standard deviation (n=10) for 5.0 μg/ml BSA was 3.94%. The method was applied to the determination of proteins in human plasma, and the results were compared with the traditional proteins assay (CBB method). There is almost no interference from amino acids, metal ions and other coexistent substances. The reaction mechanism was also discussed.     

Highly Selective Photometric Method for the Determination of Periodate

ABSTRACT

A simple and selective photometric procedure was developed for the micro-determination of periodate in aqueous media. The method is based on the reaction of periodate with Gallocyanine at pH = 4.8. The reaction was monitored photometrically by measuring the absorbance of the reaction mixture at 620 nm. The effects of reagent concentration, temperature and influence of other species for the determinations of periodate were investigated. Periodate can be determined in the range of 0.02-2.20 μg/ml, with a relative standard deviation of 1.96% for ten replicate measurements of 0.13 μg/ml periodate. Periodate can be determined in the presence of iodate or iodide.     

A Fluorescence Quenching Method for the Determination of Iodide Ion with Salicylfluorone and Hydrogen Peroxide

Abstract

A highly sensitive and selective fluorescence quenching method has been developed for rapid determination of iodide ion with salicylfluorone (SAF) as fluorogenic reagent (λ_ex = 495 nm, λ_em = 520 nm) at pH 2.5-3.0. The calibration graph is linear over the range 0.05-300 μg/25 ml. The detection limit is 0.05 μ/25 ml iodide. Other halide ions do not interfere with the determination even when present in large excess. The method is rapid and was successfully applied for the determination of iodide ion in sodium chloride, table salt and low sodium salt.     

Utility of Dihaloquinone Chlorimides for the Determination of Phenazopyridine

Abstract

Phenazopyridine was found to react with each of 2, 6-dichloroquinone chlorimide (DCQ) and 2,6-dibromoquinone chlorimide (DBQ) in the presence of sodium acetate to produce a green colour peaking at 700 nm. The produced colour was found to obey Beers law in the range of 2-25 μg/ml. The molar ratio of the reaction could be realized, and a proposal of the reaction pathway was presented. The suggested procedure could be applied successfully to the determination of phenazopyridine HCl in tablets and the results obtained were compared favourably with those given with the official method.     

Spectrophotometric Determination of Trace Amounts of Molybdenum in Steel and Pure Iron with a New Chromogenic Reagent Dimethoxyhydroxyphenylflurone

ABSTRACT

A simple method for the direct determination of trace molybdenum in low alloy steel and pure iron with selectivity and sensitivity is reported. In the presence of TritonX-100 and sulphuric-phosphoric acid medium, a new chromogenic reagent dimethoxyhydroxyphenyl-flurone (DMHPF) forms a red complex with molybdenum(VI). The molar absorptivity is obeyed from the range of 0? 8 μg/25 ml for molybdenum(VI). Most of metal ions and 35000-fold amounts of iron do not interfere with the determination of molybdenum. The proposed method has been successfully used for the determination of trace amounts of molybdenum in steel and pure iron specimens.     

Integrated Retention/Spectrophotometric Detection Method for the Determination of Formaldehyde

Abstract

An integrated-sensor method for the determination of formaldehyde based on retention of the reaction product of the analyte with p-rosaniline and sulfite in a flow-cell packed with Dowex 1-X-8 anion exchange resin was developed. The method has a good selectivity with a detection limit of 0.3 μg ml^?1 (1 ml sample) or 75 ng ml^?1 (2 ml sample), and a linear range between 1–30 μg ml^?1. The relative standard deviations (n = 11) were 2.8 and 1.3% for 2 and 20 μg ml^?1 formaldehyde, respectively. Depending on the working conditions, the sampling frenquency ranged between 10 and 18 h^?1. The method was applied to the determination of formaldehyde in well water.     

Second Derivative Ultraviolet Spectrophotometry and High Performance Liquid Chromatography with Fluorometric Detection of Cycloserine Using 9-Chloro-10-methyl Acridinium Triflate as a New UV and Fluorescent Labeling Agent

Abstract

Sensitive and simple second derivative UV spectrophotometric and HPLC with fluorometric detection methods were developed for cycloserine based on derivatization with 9-chloro-10-methyl acridinium triflate (CMAT) to yield a reaction product which absorbs in the UV at 361 nm and is fluorescent using excitation and emission wavelengths of 257 nm and 475 nm, respectively. The CMAT derivatization reaction takes 30 minutes at 70°C. Cycloserine was linear in the 0.3 – 5.0 μg/ml range (r=0.999, n=5) for the second derivative UV method and the 0.8 – 5 μg/ml range for the HPLC method (r=0.999, n=5). The limit of detection for cycloserine in the HPLC method can be improved to 0.15 μg/ml with the addition of glacial acetic acid to the analytical sample. The HPLC assay was applied to the determination of cycloserine in spiked human urine samples. The correlation coefficient (r) was in the 0.999 range and sensitivity was at the low pg/ml level.     

Spectrophotometric determination of some dibenzazepines with picryl chloride

A simple and sensitive spectrophotometric method has been developed for the determination of some dibenzazepines, based on reaction with picryl chloride in chloroform medium and measurement at 395 nm. Beer's law is obeyed in concentration ranges 0.1-1.0 microg/ml for imipramine hydrochloride, trimipramine maleate and opipramol dihydrochloride, 0.16-1.6 microg/ml for desipramine hydrochloride and 0.4-2.4 microg/ml for clomipramine hydrochloride. The method was applied successfully to the determination of dibenzazepines in tablets and the results were comparable to those obtained by official procedures.     

Microdetermination of Trace Cobalt In Water By Direct Polyurethane From Thin-Layer Spectrophotometry

Abstract

Traces of cobalt in water sample are preconcentrated into a white thin-layer of a parallelpiped polyurethane foam, by the sorption of its thiocyanate complex from acidic medium.

The cobalt thiocyanate complex possesses a blue colour in the foam matrix which has a maximum absorption at 625 nm. the absorbance of the Dlue species is mesured directly in the foam matrix at 680 625 and 540 nm. with different media in the measuring cell. the net absorbance at 625 nm is calculated using a multiwavelength program, where the value of the blank is subtracted. Beer's law is obeyed in the concentration range 0.025-2.0 μg per dl with a detection limit of 25 μg per dl for a 100 ml sample volume. the method is specific for cobalt     

Spectrophotomhtric Determination of Vanadium with Salicylic Acid in Formic Acid Medium

Abstract

A method is described for the spectrophotometric determination of vanadium by measuring its colored complex with salicylic acid in formic acid medium. Lambert-Beer's law is followed in the range of 2.0 - 32.0 μg V/ml of the final solution. Thirty-six ions were tested and did not interfore, at the established conditions.     

Kinetic Flow Injection Spectrophotometric Determination of Nitrite by its Catalytic Effect on the Oxidation of Chlorophosphonazo-pN by Bromate

Abstract

A flow injection kinetic method has been developed for the determination of nitrite, based on its catalytic effect on bromate oxidation of chlorophosphonazo-pN in H₂SO₄ medium. The reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 551 nm. The sampling frequency was 83 h^?1. The calibration curve was linear between 0.050 and 1.00 μg/ml, and the detection limit was 0.018 μg/ml. The proposed method was applied to the determination of nitrite in waters and soil with satisfactory results.