Acid In Pharmaceutical Preparations Research Articles

Kinetic study of the tartaric acid-periodate reaction: Determination of tartaric acid using an improved periodate-selective electrode

The preparation of an improved liquid-membrane periodate-selective electrode is described. The electrode exhibits rapid and near-Nernstian response in the range 2 × 10 −6-10 −2 M. The electrode was used to monitor the course of the tartaric acid-periodate reaction. A potentiometric reaction rate method for the rapid and accurate determination of tartaric acid has been developed. A total of 0.4–120 μmol of tartaric acid has been determined with relative error of about 2.0%. The method has been applied to the determination of tartaric acid in pharmaceutical preparations and to the determination of small amounts of tartaric acid in impure citric acid.

Simultaneous determination of dextropropoxyphene napsylate, caffeine, aspirin and salicylic acid in pharmaceutical preparations by reversed-phase HPLC

The official compendial method for the determination of dextropropoxyphene napsylate, caffeine, aspirin and salicylic acid involves a lengthy extraction by gas chromatography and spectrophotometry. The analytical scheme reported here provides a fast, sensitive, and stability-indicating reversed-phase HPLC assay for all these components concurrently. The total elution time is 10 min. The accuracy of the method has been tested on commercial products. The method can easily detect low levels of salicylic acid.

Microgram Determination of Ascorbic Acid in Pharmaceutical Preparations, Urine, Blood Plasma and Fruit Juices

Microgram Determination of Ascorbic Acid in Pharmaceutical Preparations, Urine, Blood Plasma and Fruit Juices

Application of differential pulse polarography to the assay of ascorbic acid

A polarographic method for the determination of ascorbic acid in pharmaceutical preparations and fruit juices is described. The method is based on the oxidation of ascorbic acid by iodine, and the resulting iodide, after removal of excess iodine, is oxidized with bromine to iodate which is measured polarographically. The method enables analysis of solutions as dilute as 1.7 × 10 −6 M ascorbic acid.

Simple and rapid spectrophotometric and titrimetric methods for the determination of ascorbic acid in pharmaceutical preparations

AbstractAscorbic acid in pharmaceutical preparations can be determined by either spectrophotometric or titrimetric methods by its reaction with ferricinium trichloroacetate at pH 3. The latter is quantitatively reduced to ferrocene. This is extracted by chloroform and its concentration calculated from the absorbance at 440 nm. Alternatively, an aqueous solution of ascorbic acid is titrated with that of the blue ferricinium salt which acts as an indicator. Vitamins, minerals, hormones, dextrose and coloured additives do not interfere with the reaction. Both methods are simple, rapid and sensitive.

Polarographic determination of folic acid in pharmaceutical preparations

A.c. polarograms of folie acid recorded from acetate buffer pH 5.5 exhibit a very welldefined wave at the dropping mercury electrode. The current is diffusion-controlled and proportional to the concentration; the optimal range of measurement is 0-24̄ μg ml -1. Two electrons and two hydrogen ions are involved in the reduction. With the phase-sensitive a.c. polarographic method, the calibration graph is linear in the 2 × 10 -8—2 × 10 -6 M range. The method proposed for the determination of folic acid in tablets is very simple and rapid, and does not involve time-consuming separation of iron salts and insoluble constituents in the tablets.

Construction, analytical study and application of a new chloramine-t selective electrode

A chloramine-T (CAT) selective electrode with a liquid membrane of nickel batho-phenanthroline—chloramine-T dissolved in 2-nitro- p-cymene is described. The liquid membrane electrode exhibits rapid and near Nernstian response to chloramine-T activity from 10 -1 to 10 -4 M. The response is unaffected by pH in the range 5–9. Major interferences are penodate and perchlorate. In analytical applications, direct potentiometnc methods for the determination of chloramme-T, ascorbic acid, and arsenic(III), and a titnmetric method for ascorbic acid are described. Ascorbic acid and arsenic(IU) in the ranges 0.4–40 and 0.5–2 mg, respectively, can be determined with relative errors of 1–2%. The method has been applied to the determination of ascorbic acid in pharmaceutical preparations.

Colorimetric determination of folic acid in pharmaceutical preparations.

A colorimetric method, based on colour development with 1,2-naphtho-quinone-4-sulphonic acid, sodium salt, has been developed for the determination of folic acid. The method depends on the availability of the primary amino group that is liberated on reduction of folic acid. The colour produced has an absorbance maximum at 485 nm and obeys Beer's law in the concentration range 11·7 to 58·7 µg ml–1. The method has been used successfully for assaying folic acid, tablets containing folic acid alone or in combination with iron and vitamin B12, and injections of folic acid.

Colorimetric determination of ascorbic acid.

Ascorbic acid reacts with diazotizedp-aminobenzoic acid in alkaline medium giving pink color which obeys Beer's law from 600μg to 2 mg/30 ml. The method has been used for the determination of ascorbic acid in pharmaceutical preparations containing sugars and other vitamins.

Spectrophotometric determination of ascorbic acid with potassium hexacyanoferrate(III)

A new, simple and rapid method of determination of ascorbic acid in amounts of 45–360 μg is described. The ascorbic acid is determined spectrophotometrically at 420 nm from the decrease in absorbance it causes in 1 × 10 −3 M hexacyanoferrate(III) in McIlvaine buffer at pH 5·2. The proposed method is suitable for the determination of ascorbic acid in pharmaceutical preparations and probably natural products.

The Chemical Determination of Folic Acid in Pharmaceutical Preparations

The procedure of Hutchings, et al., has been modified for use with pharmaceutical preparations containing colored materials such as iron salts, liver, vitamins, etc. Concentrations of folic acid as low as 0.01 per cent can be accurately determined in the presence of these colored materials by using the modified procedure. Illustrations are given of how the method was evolved. A curve was prepared for commercial folic acid and water solution using para-amino benzoyl glutamic acid as a primary standard. One by one the colored ingredients were added and the curves examined in turn. The effect of increments of folic acid was studied. Assays were checked at different dilutions. Finally, aged samples of dark solutions were tested by both the chemical and microbiological assays and the results compared.