scholarly journals Automatic continuous on-line monitoring of salicylic acid and acetylsalicylic acid in pharmaceuticals

1990 ◽  
Vol 12 (6) ◽  
pp. 263-266 ◽  
Author(s):  
J. M. López Fernández ◽  
M. D. Luque de Castro ◽  
M. Valcárcel

An asymmetrical FIA merging-zones manifold based on the dual injection of two sample microvolumes was developed for the simultaneous determination of salicylic acid and acetylsalicylic acid in pharmaceutical preparations at a sampling frequency of 30/h. The complex formed between the Fe(III) reagent continuously introduced in the system and salicylic acid was monitored photometrically at 520 nm. One of the sample plugs was prehydrolysed on injection into an NaOH stream and was circulated through a longer channel than the other plug. This yielded two FIA peaks corresponding to salicylic acid and the overall content, respectively. The proposed manifold was successfully used to control the dissolution test of a pharmaceutical preparation.

2001 ◽  
Vol 84 (3) ◽  
pp. 676-683 ◽  
Author(s):  
Natividad Ramos-Martos ◽  
Francisco Aguirre-Gómez ◽  
Antonio Molina-Díaz ◽  
Luis F Capitán-Vallvey

Abstract This paper describes a rapid reversed-phase liquid chromatographic method, with UV detection, for the simultaneous determination of acetylsalicylic acid, caffeine, codeine, paracetamol, pyridoxine, and thiamine in pharmaceutical preparations. A reversed-phase C18 Nucleosil column is used. The mobile phase consists of 2 successive eluants: water (5 min) and acetonitrile–water (75 + 25, v/v; 9 min), both adjusted to pH 2.1 with phosphoric acid. Before determination acetylsalicylic acid is completely converted to salicylic acid by alkaline hydrolysis. Salicylic acid, caffeine, paracetamol, pyridoxine, and thiamine are all detected at 285 nm, whereas codeine is detected at 240 nm. Calibration curves were linear for salicylic acid, caffeine, paracetamol, and pyridoxine in the range of 50–500 mg/L, and for codeine and thiamine in the range of 50–1000 mg/L. The method was applied to the analysis of 13 fortified commercial pharmaceutical preparations. Recoveries ranged from 92.6 to 105.5%, with relative standard deviations of 1.1–5.8%.


2011 ◽  
Vol 65 (6) ◽  
Author(s):  
Mehmet Caglayan ◽  
Ismail Palabiyik ◽  
Mustafa Bor ◽  
Feyyaz Onur

AbstractSimultaneous determination of enalapril maleate (ENA) and nitrendipine (NIT) in pharmaceutical preparations was performed using liquid chromatography (LC) and the partial least-squares-1 (PLS-1) method. In LC, the separation was achieved on a C8 column and the optimum mobile phase for good separation in a gradient elution programme was found to be acetonitrile-water (φ r = 81: 19) and optimum flow-rate, temperature, injection volume, and detection wavelength were set at 1.0 mL min−1, 25°C, 10 μL, and 210 nm, respectively. Dienogest was selected as an internal standard. In the spectrophotometry, a PLS-1 chemometric method was used. The absorbance data matrix related to the concentration data matrix was established by measurement of absorbances in their zero order spectra with an increment of Δλ = 1 nm in the 220–290 nm range for ENA and with Δλ = 1 nm in the 230–290 nm range for NIT in the PLS-1 method. Following this step, calibration was established by using this data matrix to predict the unknown concentrations of ENA and NIT in their binary mixture. These optimised methods were validated and successfully applied to a pharmaceutical preparation in tablet form and the results were subjected to comparison.


2010 ◽  
Vol 93 (3) ◽  
pp. 862-868 ◽  
Author(s):  
Mehmet Gökhan Çağlayan ◽  
Ismail Murat Palabiyik ◽  
Feyyaz Onur

Abstract Simultaneous determination of dienogest (DIE) and estradiol valerate (EST) in sugar-coated tablets was performed by using HPLC and spectrophotometry. In HPLC, the separation was achieved on an ACE C8 column using the mobile phase acetonitrileNH4NO3 (0.03 M, pH 5.4; 70 + 30, v/v) at a flow rate of 2 mL/min. The detection wavelength was 280 nm, and cyproterone acetate was selected as an internal standard. The linearity range was 3.045.0 g/mL for DIE and 18.0100.0 g/mL for EST. As spectrophotometric methods, two chemometric methods, principal component regression and partial least-squares, were developed. In the chemometric techniques, the concentration data matrix was prepared by using mixtures containing these drugs in methanolwater (3 + 1, v/v). The absorbance data matrix corresponding to the concentration data matrix in these methods was obtained by the measurement of absorbances in their zero-order spectra; then, the calibration was obtained by using the data matrix for the prediction of unknown concentrations of DIE and EST in their binary mixture. Working ranges were found as 2.024.0 g/mL for DIE and 20.0270.0 g/mL EST in the methods. These three developed methods were validated and successfully applied to a pharmaceutical preparation, a sugar-coated tablet, and the results were compared with each other.


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