A.S. Issa

The use of chloranil for spectrophotometric determination of some tranquillizers and antidepressants.

Chlorpromazine hydrochloride, promethazine hydrochloride, promazine hydrochloride, perphenazine, thioridazine hydrochloride, chlorprothexine, opipramol hydrochloride, amitriptyline hydrochloride, imipramine hydrochloride and hydroxyzine hydrochloride are estimated in their pure state and in pharmaceutical formulations by means of the reaction of the free bases with chloranil in dioxan-ethanol medium to give a coloured product with maximal absorbance at 550 nm. The method is precise, accurate and specific and recommended for routine analysis for the drugs mentioned.

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 p-chloranilic acid for the colorimetric determination of some antimalarials

A simple and sensitive colorimetric method for the assay of quinine sulphate, primaquine diphosphate, amodiaquine hydrochloride and pyrimethamine is described. The method is based on the interaction of the drugs and p-chloranilic acid to give a stable product with an intense colour which can be used for the determination of these antimalarials in their pharmaceutical preparations.

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 Beers law enabled the determination of these drugs in their pharmaceutical preparations. The assay results are in accord with the pharmacopoeal assay results.

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.

The use of 2,3-dichloro-5,6-dicyano-p-benzoquinone for the spectrophotometric determination of some cardiovascular drugs.

Some basic cardiovascular drugs containing secondary or tertiary amino groups are determined spectrophotometrically. The method is simple and sensitive; it is based on the interaction of the drugs, as n-electron donors, with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) as a pi-acceptor. The highly coloured radical anion exhibits maximum absorption at 460 nm. The drugs determined are pindolol, dipyridamole, hydralazine hydrochloride, quinidine sulphate, prenylamine lactate and tolazoline hydrochloride. Beers law is obeyed for these drugs. The procedure is sensitive enough to permit unit dose assay of the individual drugs in their pharmaceutical formulations. The assay results are in accord with the pharmacopoeial assay results.

Titrimetric determination of some phenothiazine derivatives, with ferricyanide.

Six phenothiazine drugs (chlorpromazine hydrochloride, promethazine hydrochloride, promazine hydrochloride, perphenazine, acetophenazine maleate and trifluoperazine hydrochloride) have been determined by titration with potassium ferricyanide in phosphoric acid medium with Methylene Blue as a screening indicator. The results were in agreement with those obtained by the official methods.

Oxidants for the colorimetric determination of pindolol

A simple, sensitive and accurate colorimetric method is described for the quantitative determination of pindolol either in the pure form or in its tablets. The method is based on the oxidation of the indole moiety in pindolol with potassium persulphate or hydrogen peroxide-in acid medium-to give a highly coloured product that exhibits maximum absorption at 535 nm and 570 nm, respectively. Beers law is obeyed over concentrations ranging from 0.07-0.35 mg/10 ml for potassium persulphate and 0.1-0.5 mg/10 ml for hydrogen peroxide with mean recoveries of 99.6+/-0.6 and 99.8+/-0.9%, respectively. The method is applied for the assay of pindolol tablets without any interference due to tablet fillers.

A Sensitive Spectrophotometric Method for the Determination of Some Imidazoline Derivatives by 2,6-Dichlorophenol-Indophenol

Abstract A new and highly sensitive method is presented for the spectrophotometric determination of four imidazoline derivatives: antazoline hydrochloride, tolazoline hydrochloride, xylometazoline hydrochloride and naphazoline nitrate. The method is based on the reaction of the corresponding drug base with 2,6 - dichlorophenol -indophenol (DGPIP) in chloroform to give a blue chromogen exhibiting a maximum at 588 - 603nm. The method could be applied for the quantitative determination of the above drugs either pure or in their pharmaceutical preparations (tablets and nasal drops). The results obtained are accurate and have good reproducibility.