Y. A. Beltagy

Spectrophotometric determination of some phenothiazine derivatives and opipramol with chloramine-T.

This paper describes a spectrophotometric method for the assay of phenothiazines (and also opipramol, which is similar but contains a CC linkage instead of the S atom of the phenothiazines) as the pure drug or in tablets or solutions for injection. The colour is produced by heating a solution of the drug or drug preparation with a solution of chloramine-T. The coloured product can be extracted into chloroform before the colour measurement or the whole process carried out in ethanol solution, the colour of which is then measured.

Pharmaceutical analysis of some tranquillizers and antidepressants with iodine monochloride.

A titrimetric method for the evaluation of some tranquillizers and antidepressants is proposed. The method is based on the oxidation of these drugs by iodine monochloride, in strong acid medium, the iodine liberated being titrated with potassium iodate by the Andrews method. The proposed method is applied successfully for the determination of 9 phenothiazines, 1 thioxanthene, 2 acid hydrazides and 1 dibenzazepine containing a double bond (Opipramol). Tablets, solutions for injection, and drops are also determined by the proposed method. The mechanism of oxidation for each species is suggested and the results obtained agree with these suggestions. Some official and non-official methods for the evaluation of the drugs have been compared with the iodine monochloride method, which is found to be superior in specificity, sensitivity and speed.

Use of Differential Spectrophotometry for Determination of Cytarabine and Acyclovir in Their Dosage Forms

Abstract Differential (ΔA), first derivative- (ΔD1) and second derivative- (ΔD2) differential ultraviolet spectrophotometric methods have been presented for the quantitation of cytarabine and acyclovir in their pharmaceutical formulations such as injections and creams. The methods are based on measuring ΔA, ΔD1 and ΔD2 of the active ingredients in acidic solutions against their basic solutions as blanks. The proposed methods are sensitive, highly specific and advantageous over the conventional UV assays since all interferences of the excipients or irrelevant absorptions are nullified. Accuracy of the analysis with the proposed procedures is significantly greater than the classical spectrophotometry methods.

New Sensitive Method for the Analysis of Some Non UV Absorbing Quaternised Compounds

Abstract A rapid first derivative spectrophotometric assay of bretylium tosylate, hyoscine butylbromide, oxyphenonium bromide, cetrimide and benzalkonium chloride in pure and in pharmaceutical formulation is developed, The assay depends upon extracting the picrate salt of these quaternised compounds into chloroform from aqueous medium and measurement of peak amplitude at 430 nm or peak - trough amplitude at 365/330 nm. Linear correlation over the concentration range of 5–20 ug ml−1 of the investigated compounds is obtained. The recovery percentage of the pure compound varied from 99.5 to 100.6%. The developed method is simple, sensitive, accurate and suitable for routine analysis of these quaternised compounds in bulk powder and in pharmaceutical formulations.

Some spectrophotometric methods for determination of certain antipyretic and antirheumatic drugs

Heating paracetamol in strongly alkaline medium with 4-nitrosoantipyrine gives a red colour with maximum absorption at 515 nm. Mefenamic and flufenamic acids can be determined colorimetrically after extraction as ion-pairs with Methylene Blue.

Spectrophotometric determination of some penicillins with ammonium vanadate.

A spectrophotometric method for determining some penicillins has been developed. A known volume of the penicillin solution-in phosphate buffer of pH 6.8 is boiled with ammonium vanadate solution-in sulphuric acid medium-for 10 min and the absorbance of the colour formed is measured at 750 nm. The excess of vanadate can also be determined volumetrically. The method has been successfully applied for the determination of penicillin G sodium, phenoxymethyl penicillin, ampicillin sodium, phenethicillin potassium, cloxacillin sodium and methicillin sodium. The procedure is also used for analysing some pharmaceutical preparations of these drugs, e.g., injections. The results obtained are in agreement with those of the B P 1973 methods.

Spectrophotometric determination of cefprozil in pharmaceutical dosage forms, in urine and in the presence of its alkaline induced degradation products

Four simple, rapid and accurate methods for spectrophoto-metric determination of cepfrozil are presented. Method I and II depend on measuring first derivative peak-trough amplitude of the drug in 0.1 N HCl (D1 a) and in phosphate buffer pH 7(D1 b), respectively. Method III and IV are based on measuring the absorbance difference (ΔA) and first derivative difference (ΔD1) of buffered cefprozil solutions against its acidic solutions as blanks. The proposed methods are applied for the determination of the drug in pure and dosage forms with good accuracy and precision. Among the previously mentioned methods; D1 a, D1 b and ΔD1 are used for the determination of cefprozil in urine. These methods have been successfully applied for the determination of cumulative amounts of cefprozil in urine following an oral dose of 500 mg to a human male volunteer. Moreover, by using D1 a method and applying the zero-crossing technique, both the intact drug and its alkaline induced degradation products could be determined in presence of each other without interference. The proposed methods proved to be accurate and reproducible.

Simultaneous Quantitation of Minoxidil and Tretinoin in Magistral and Pharmaceutical Preparations by First Derivative Spectrophotometry

Abstract A first derivative spectrophotometry method has been developed for the simultaneous quantitation of minoxidil and tretinoin. The method is based on measuring the first derivative signals (D1) of minoxidil and tretinoin at 290 and 351 nm, respectively, without any interference from each other, or any other coexisting materials. Beers law was valid over the concentration range 2–10 μg/ml of minoxidil and 0.25–1.25 μg/ml of tretinoin. The proposed method has been applied successfully to the determination of some magistral and pharmaceutical preparations. Relative standard deviations for the assay of both drugs were less than 0.95%.

Application of some colorimetric methods for the spectrophotometric determination of phenylbutazone and oxyphenbutazone

Two methods for determination of phenylbutazone and oxyphenbutazone are described. In the first, naphthoquinone reacts with the product of acid hydrolysis of phenylbutazone or oxyphenbutazone to give an orange colour, having maximum absorption at 480 and 465 nm respectively. In the second, lead tetra-acetate reacts with the hydrolysis product of phenylbutazone (benzidine) to develop a green colour which on heating or addition of excess of reagent changes to yellow, with maximum absorption at 340 nm. Oxyphenbutazone gives a yellow colour with the reagent in the cold, with maximum absorption at 359 nm.

Determination of Canrenone in Spironolactone Using Second Derivative Spectrophotometry

Abstract Second derivative spectrophotometry has been used to determine canrenone (I), the main degredation product in spironolactone (II). Second derivative at 300 nm was found linearly related to concentration in the range of 0.2–1 mg% I has been determined in II down to concentration level of 0.2 mg%. The results were found reproducible with a relative standard deviation of 1.7%.