Simultaneous spectrophotometric and volumetric determinations of amoxycillin, ampicillin and cloxacillin in drug formulations: reaction mechanism in the base catalysed hydrolysis followed by oxidation with iodate in dilute acid solution.

A method for the analysis of degraded products of amoxycillin, ampicillin and cloxacillin in drug formulations, obtained as a result of their base hydrolysis is described. Simultaneous spectrophotometric and volumetric determinations of the antibiotic is based on the neutralization of the degraded product by dilute hydrochloric acid to get a pH approximately 2 to be conducive for redox titration using potassium iodate as titrant. A red purple colour is developed in carbon tetrachloride at the end point. Spectrophotometry is done after separating the organic layer and measuring the absorbance of red-purple colour at lambda(max) 520 nm. The pathways of different degraded products and their oxidation mechanism is described on IR, TLC and UV spectroscopic studies.

Resin bead detection and spectrophotometric determination of oxyphenbutazone with p-dimethylaminocinnamaldehyde: Application to bulk drug and dosage forms.

An analytical method for resin bead detection and spectrophotometric determination of oxyphenbutazone with p-dimethylaminocinnamaldehyde as a reagent is described. Acid hydrolysed product of oxyphenbutazone produced a red color product with p-dimethylaminocinnamaldehyde that absorbs maximally at 520 nm. The detection limit is 0.8 mug in resin phase and 4.0 mug in aqueous phase. Beer's law is obeyed in the concentration range of 0.4-4.0 mug/ml of oxyphenbutazone. The method is unaffected by the presence of acetylsalicylic acid, salicylamide, phenylbutazone and number of other excipients but paracetamol gives a positive reaction and novalgin being reductone interferes with the test, both should be removed by extraction with dilute sulfuric acid.

Extraction spectrophotometric method for the determination of ascorbic acid in pharmaceutical preparations, urine and fruit juices with potassium iodate.

An indirect determination of ascorbic acid is based on extraction of the iodine produced by reduction of potassium iodate. Beer's law is obeyed over the range 0.02-0.36 mg/ml ascorbic acid.

Filter-paper test for microgram detection of aliphatic amines.

A new simple, sensitive and selective test for the detection of microgram amounts of aliphatic amines with diphenylcarbazide-soaked Whatman No. 1 filter paper as the detection medium is described. A feature of the study is the observation that the reaction does not take place in solution in the absence of the filter paper.

Spectrophotometric determination of novalgin in tablets by use of potassium iodate.

An indirect colour reaction has been studied for determination of novalgin in tablets. The method is simple, rapid and reproducible with a relative standard deviation of 0.2%. Novalgin is determined spectrophotometrically by means of its colour reaction with potassium iodate. Beer's law is obeyed over the range 1-10 mg of drug. A tentative reaction mechanism has been proposed.

Ion exchange method for rapid determination of alkalinity of water-soluble tea ash containing high levels of manganese.

An ion exchange method to determine the alkalinity of water-soluble tea ash containing high levels of manganese is described. A chromatographic column containing a strong cation exchange resin (20-50 mesh) in Na+ form, with a bed volume of 5 mL is used. The present ion exchange method is compared to pH titrations and also to the official AOAC methods (31.012, 31.015, 31.016). Results with the new method are accurate and precise.

Microgram detection of phenols and determination of nitro- and nitroso-phenols.

The microgram detection of phenols and determination of nitro- and nitroso-phenols is based on their treatment in alkaline solution with a chlorinated hypochlorite solution, resulting in characteristic colours. Ion-exchange resin beads are used to make the test sensitive and selective. A few nitro and nitroso compounds have been determined spectrophotometrically.

Selective role of oxidants in the presence of cation-exchange resins in Na(+)-form for the detection and differentiation of acidic, basic and neutral amino-acids.

A test for detection and differentiation of acidic, basic and neutral amino-acids is based on use of a sulphonic acid cation-exchange resin in Na(+)-form, in the presence of various oxidants (permanganate, dichromate, chromate, iodate, peroxide) and final detection with Nessler's reagent.

A new ion-exchange test for detection of ketones on the microgram scale.

A test for the detection of certain ketones is based on the reaction with 1-chloro-2,4-dinitrobenzene in the presence of an anion-exchange resin in the OH(-) form, to give a violet colour on the resin bead surface.

Organic and inorganic ion-exchange beads as indicators in redox and precipitation titrations.

Resin beads in the Fe(III) or p-dimethylaminobenzylidene-rhodanine form are used as indicators in precipitation titrations with K(3)Fe(CN)(6), and Ag(+). Resin beads with dipheny lamine adsorbed on them can be used as indicators in cerimetric titrations. They have some advantages over conventional indicators.