Determination of salicylic acid and aspirin in multicomponent tablets by liquid chromatography on a nonionic resin

Fast and single solid phase fluorescence spectroscopic batch procedure for (acetyl) salicylic acid determination in drug formulations

A solid phase fluorescence spectroscopic batch procedure for (acetyl) salicylic acid in drug formulations have been developed. The procedure is based on the sorption of salicylic acid (SA) on Sephadex DEAE A-25 anion exchanger gel (100 mg) by equilibration from an aqueous solution (10 or 25 ml) for 5 min; the equilibrated gel is transferred into an 1 mm quartz cell and the native fluorescence of SA sorbed on it is directly measured (lambda(ex)=297 nm; lambda(em)=405 nm). Good linearity was found in the 10-200 and 5-100 microg l(-1) ranges (for 10 and 25 ml sample volume, respectively) with R.S.D. (%) of 2.8 and 1.1. The procedure was successfully applied to the determination of acetyl salicylic acid (ASA) in drug formulations after alkaline hydrolysis to yield SA.

Simultaneous determination of acetaminophen, acetylsalicylic acid and ascorbic acid in tablet form using HPLC

The purpose of the present study was to develop a simple and accurate HPLC method to measure the amount of each agent in a multidrug pharmaceutical formulation. Three drugs, acetaminophen, acetylsalicylic acid and ascorbic acid, were analyzed simultaneously. A commercial pharmaceutical effervescent tablet was examined and the amount of each of these agents successfully determined. The present method appears to be more convenient than the current procedures described in American and British Pharmacopoeias in which each drug is assayed separately.

Development and validation of a dissolution method for warfarin sodium and aspirin combination tablets

A dissolution method for warfarin sodium-aspirin combination tablets was developed which utilizes USP Apparatus 1 (baskets) at 50 rpm with 900 ml of phosphate buffer (pH 6.8; 0.05 M) medium at 37 degrees C. A reversed-phase liquid chromatographic method was also developed for the simultaneous determination of warfarin sodium, aspirin and salicylic acid on an octadecylsilica column using acetonitrile-tetrahydrofuran-glacial acetic acid-water (23:5:5:67, v/v/v/v) as the mobile phase with UV detection at 282 nm. Validation data were obtained which demonstrate that the dissolution methodology is accurate, precise, linear and rugged for the combination tablets.

Comparison of three new spectrophotometric methods for simultaneous determination of aspirin and salicylic acid in tablets without separation of pharmaceutical excipients

Simultaneous analysis of aspirin (ASA) and salicylic acid (SA) in pharmaceutical tablet preparations was performed by two multicomponent UV-spectrophotometric methods utilizing principal component regression and classical least square algorithm. Additionally, an assay procedure based on second-derivative spectroscopy was developed. The analysis was performed in turbid solutions without separation of interfering excipients. The range, as determined by the second-derivative methods, was 0.2 to 103.2 micrograms/mL for ASA and 0.07 to 44.5 micrograms/mL for SA. Sensitivity for determination of SA was 0.004% of ASA content for the second-derivative method and 0.2% of ASA content for both multicomponent methods. The methods were applied to laboratory mixtures and commercial tablet formulations containing ASA and SA. The advantage of the second-derivative method in determining small amounts of SA in commercial tablet preparations is shown in comparison with a conventional HPLC method. All UV-spectrophotometric methods are rapid, accurate, and reproducible.

Determination of aspirin by pre-column transacetylation reaction of 3-aminophenol and reversed-phase high-performance liquid chromatography: simultaneous determination of aspirin, acetaminophen, and caffeine

The accuracy of the measurement of aspirin by high-performance liquid chromatography (HPLC) is reduced by its hydrolysis into salicylic and acetic acids during sample preparation. The ready and quantitative transacetylation of 3-aminophenol by aspirin, giving 3-hydroxyacetanilide (which is stable), has been utilized as a pre-column reaction for the determination of aspirin either alone or in the presence of acetaminophen and caffeine by reversed-phase HPLC.

Quantitative determination by high-performance liquid chromatography of acetylsalicylic acid and related substances in tablets

High-performance liquid chromatography on a Zorbax C8 7-micron column (25 cm X 0.46 cm I.D.) with methanol-water-1 M phosphoric acid (59:36:5) as the mobile phase has been used for the analysis of several naturally aged batches of fourteen brands of acetylsalicyclic acid tablets. The extraction solvent is methanol, containing 2% v/v of formic acid. Salicylic acid is the main impurity. Acetylsalicylsalicylic acid is the second most important impurity, and the corresponding salicylsalicylic acid is rarely present. Buffered or dispersible tablets contain relatively more of the latter two impurities and eventually also the corresponding higher oligomers. Acetylsalicylic anhydride is always a minor impurity. Comparison is made with classical spectrophotometric methods, which are observed to be selective for salicylic acid.

Analysis of a complex analgesic formulation by high-performance liquid chromatography with column-switching

An isocratic method is described which allows the complete separation of acetylsalicylic acid, paracetamol, caffeine, carbromal, bromisoval and codeine as well as the potential impurities salicylic acid, diacetyl-p-aminophenol and acetylcodeine. A column-switching technique was developed employing two columns (10 cm and 25 cm) containing 7-microm Zorbax C(8) material. The separation is better and faster than that obtained with a gradient elution method.

Simultaneous high-performance liquid chromatography assay of acetylsalicylic acid and salicylic acid in film-coated aspirin tablets

A reversed-phase high-performance liquid chromatography (HPLC) method has been developed for the simultaneous assay of acetylsalicylic acid (I) and salicylic acid (II) in film-coated aspirin tablets. As little as 0.1% II (relative to I) can be quantitatively determined. Using a 5-microns octadecylsilane column with water-acetonitrile-phosphoric acid (76:24:0.5) as the mobile phase enabled the chromatographic separation to be completed in 4 min. Due to the slow rate of decomposition of I to II in the extraction solvent, acetonitrile-methanol-phosphoric acid (92:8:0.5), the analysis of many samples was routinely performed by means of automated HPLC equipment. Other compounds (non-aspirin salicylates, caffeine and acetaminophen) were also separated by the chromatographic system.

Analysis of tablets containing aspirin, acetaminophen, and ascorbic acid by high-performance liquid chromatography

The high-performance liquid chromatographic method described enables the quantitation of the components and the main impurities of tablets containing aspirin, acetaminophen, and ascorbic acid. A C8 reverse-phase column was used; the mobile phase was methanol-0.2 M phosphate buffer (pH 3.5)-water (20:10:70). Results obtained for a brand of effervescent tablets, normally aged for 5 years and stressed at 37 degrees C, 50 degrees C, or in 79% relative humidity at room temperature, are reported. Salicylic acid was the main product of decomposition. Diacetyl-p-aminophenol was observed to be formed by transacetylation.

Stabilized normal-phase high-performance liquid chromatographic analysis of aspirin and salicylic acid in solid pharmaceutical dosage forms

A simultaneous analysis of aspirin and nonaspirin salicylates in solid pharmaceutical dosage forms is described. Two separate extraction procedures are employed, one for plain aspirin tablets and one for tablets containing aspirin plus buffers or antacids. The analyses of the extracted samples are accomplished by a stabilized normal-phase high-performance liquid chromatographic (HPLC) procedure. Prepared samples and standards are stable for up to 24 h, and the methodology is suitable for an automated HPLC system.

Simultaneous determination of aspirin and salicylic acid in bulk aspirin and in plain, buffered, and enteric-coated tablets by high-pressure liquid chromatography with UV and fluorescence detectors

A quantitative high-pressure liquid chromatographic method that uses a reversed-phase column coupled to UV and fluorescence detectors was developed to determine aspirin and salicylic acid in bulk aspirin and in plain, buffered, and enteric-coated tablets. The aspirin was dissolved, filtered, and injected into the chromatograph. The UV absorbance of aspirin was determined at 254 nm, and the fluorescence of salicylic acid was measured at 425 nm. Excipients and impurities did not interfere. Recoveries of 100% were obtained for aspirin and salicylic acid from simulated tablet formulations. Results obtained by the USP XIX procedure and the proposed method were compared. The coefficient of variation for the aspirin analysis was 0.59%; for salicylic acid, it was 1.69%. The rate of hydrolysis of aspirin to salicylic acid in the solvents used was < 0.05%/hr.

Aspirin--a national survey II: Determination of salicylic acid in bulk aspirin and aspirin formulations by high-pressure liquid chromatography using a fluorescence detector

A quantitative high-pressure liquid chromatographic method, using a reversed-phase column coupled to a fluorescence detector, was developed to determine salicylic acid in bulk aspirin and plain and buffered aspirin tablets. The aspirin was dissolved, filtered, and injected into the chromatograph; the fluorescence of the salicylic acid was measured at approximately 425 nm. Excipients and impurities did not interfere, and recoveries of 100% were obtained. The method was used to analyze 84 aspirin samples.

High-pressure liquid chromatographic determination of salicylic acid in aspirin powder and pharmaceutical dosage forms

A sensitive, simple, and rapid method for the quantitation of salicylic acid in aspirin powders and its dosage forms was developed. The method is based on reversed-phase high-pressure liquid chromatography using a mobile phase containing 20% methanol in aqueous phosphate buffer of pH 2.3. Other common ingredients present with aspirin such as acetaminophen, caffeine, codeine phosphate, phenacetin, and salicylamide do not interfere. Salicylic acid quantities as low as 0.1 microgram can be assayed with a relative standard deviation of +/- 2.3%. Sensitivity can be increased by using lower sensitivity settings. The method was tried on numerous commercial products and an old aspirin powder. The results generally were excellent, except that all of the aspirin and salicylic acid could not be extracted from suppositories. The old aspirin powder failed the USP limit test for salicylic acid. The powder apparently absorbed moisture and contained salicylamide as an impurity.

Simultaneous quantitation of acetaminophen, aspirin, caffeine, codeine phosphate, phenacetin, and salicylamide by high-pressure liquid chromatography

A method for the simultaneous quantitation of acetaminophen, aspirin, caffeine, codeine phosphate, phenacetin, and salicylamide was developed. The method is based on reversed-phase high-pressure liquid chromatography with a mobile phase buffered with phosphate (pH 2.3). The procedure not only separated these six active ingredients but also salicylic acid, the major decomposition product of aspirin. The method gave excellent results for three commercial products and a synthetic mixture containing four active ingredients. Lowering the pH increased the retention time of some weak acids and decreased that of some weak bases. Only these changes in the retention times made the separation possible.