Sensitive spectrophotometric determination of atenolol in pharmaceutical formulations using bromate-bromide mixture as an eco-friendly brominating agent

Three simple and sensitive spectrophotometric methods are proposed for the determination of atenolol (ATN) in bulk drug and tablets. The methods are based on the bromination of ATN by the bromine generated in situ by the action of the acid on the bromate-bromide mixture followed by the determination of unreacted bromine by reacting with a fixed amount of either meta-cresol purple (MCP) and measuring the absorbance at 540 nm (method A) and 445 nm (method B) or erioglaucine (EGC) and measuring the absorbance at 630 nm (method C). Beer's law is valid within the concentration ranges of 1.0-20.0, 2.0-40.0 and 1.0-8.0 μg/mL for method A, method B and method C, respectively. The calculated molar absorptivities were found to be 1.20×10(4), 4.51×10(3) and 3.46 × 10(4)  L/mol · cm for method A, method B and method C, respectively. Sandell's sensitivity values, correlation coefficients, limits of detection and quantification are also reported. Recovery results were statistically compared with those of a reference method by applying Student's t- and F-test. The novelty of the present study is the measurement of two different colors using MCP, that is, red-pink color of MCP in acid medium at 540 nm and yellowish-orange color of brominated MCP at 445 nm.

Determination of atenolol in pharmaceutical formulations by diffuse reflectance spectroscopy

A simple analytical method for quantification of atenolol in pharmaceutical formulations by diffuse reflectance spectroscopy is described. The method is based on the reaction, on the filter paper surface, between the drug and p-chloranil producing a colored compound. The best reaction conditions were obtained with 20 µL of atenolol solution and 20 µL of p-chloranil. All reflectance measurements were carried out at 550 nm and the linear range was from 1.13x10-2 to 7.88x10-2 mol L-1 (r = 0.9992). The limit of detection was 2.80 x 10-3 mol L-1. The proposed method was successfully applied to analysis of different commercial brands of pharmaceutical formulations and the results obtained by the proposed method were in good agreement with those obtained using the British Pharmacopoeia method.

Preparation of a Novel Iodide-Selective Electrode Based on Iodide-Miconazole Ion-Pair and Its Application to Pharmaceutical Analysis

An iodide-miconazole ion-paired complex was used as a suitable ion-exchanger for the preparation of a plasticized-PVC membrane electrode. Among different solvent mediators tested, dioctylsebacate exhibited the proper response characteristics, including Nernstian slope of the calibration curve, fast response time and good reproducibility of the emf values. The electrode exhibits a Nernstian slope of -59.8 +/- 0.5 mV decade(-1) for I- ion over a concentration range of 1.0 x 10(-5) - 1.0 x 10(-2) M with a limit of detection of 7.0 x 10(-6) M. The electrode displays a good selectivity for I- with respect to a number of inorganic and organic species. It canbe used over a pH range of 2.5 - 8.5. The membrane sensor was successfully applied to the determination of iodide in water samples and blood serum, as well as in pharmaceutical products such as iodoquinol and thyroxin.