Simultaneous estimation of amlodipine and atorvastatin by micelle-augmented first derivative synchronous spectrofluorimetry and multivariate analysis

Utilization of erythrosine B in spectrofluorimetric quenching analysis of amlodipine and perindopril in pharmaceutical and biological matrices

A spectrofluorimetric approach that is sensitive, simple, validated, and cost-effective has been proposed for the estimation of amlodipine (AML) and perindopril (PER) in their bulk powders, pharmaceutical formulations, and spiked human plasma. The recommended approach utilized the quantitative quenching effect of the two cited drugs on the fluorescence intensity of erythrosine B, as a result of complex binary reactions among each drug with erythrosine B at pH 3.5 (Teorell and Stenhagen buffer). The quenching of erythrosine B fluorescence was recorded at 554 nm after excitation at 527 nm. The calibration curve was detected in the range 0.25-3.0 μg ml-1 , with a correlation coefficient of 0.9996 for AML, and 0.1-1.5 μg ml-1 , with a correlation coefficient of 0.9996 for PER. The established spectrofluorimetric approach was validated for the estimation of the cited drugs with high sensitivity regarding International Council on Harmonization guidelines. Therefore, the established approach could be utilized for quality control of the cited drugs in their pharmaceutical formulations.

A New method for simultaneous qualitative and quantitative determination of amlodipine besylate and atorvastatin calcium in bulk and pharmaceutical formulations using transmission FT-IR spectroscopy

A simple, precise, rapid, and eco-friendly FTIR spectrophotometric method was developed and validated for simultaneous analysis of amlodipine (AML) and atorvastatin (ATV) in drug combination preparations. Firstly, synthetic mixtures were made and scanned with FTIR instrument. Then the result spectra were converted automatically to absorbance spectra. The calibration model was made depending on Beer's law which relates concentration to absorbance. Two characteristic bands corresponding to the carbonyl group at 1708-1688 cm^-1 and 1660-1632 cm^-1 for AML and ATV, respectively, were selected for quantification. The absorbance of a series of standards was measured as the AUC of the chosen bands. Then, the calibration line was obtained by plotting the measured AUCs and the actual concentrations against each other. Validation tests were performed per ICH recommendations. Specificity was evaluated by the separation of APIs and excipients from marketed preparations by methanol. Then, the spectra of extracted excipients, APIs, and pharmaceutical samples were taken and overlapped. The selected peaks were specific and did not interfere with each other or other peaks from the excipients used in the tablet's matrix. Linearity for AML and ATV was in the range of 0.1-1% w/w with excellent coefficients of determination (R²), 0.998 and 0.999 for AML and ATV, respectively. The proposed analytical method was accurate and precious, as the RSD values were less than 2%. The proposed FTIR method was successfully applied to estimate the exact quantity of APIs in pharmaceutical samples. Recoveries were accepted in accordance with USP and were in the range of 94.62-100.6% and 98.175-101.06% for AML and ATV, respectively. Likewise, the acquired results were compared with the HPLC method. And the t- and F- tests were calculated and compared with the theoretical values, which indicate the similarity of results in both developed and reported methods.

Spectrofluorimetric assay of amlodipine and perindopril in their raw materials, pharmaceutical formulations and spiked human plasma through the formation of complexes with Eosin Y

For quantitation of amlodipine (AML) and perindopril (PER) in their authentic, pharmaceutical formulations and spiked human plasma, a simple, sensitive, validated and inexpensive spectrofluorimetric method has been developed. The proposed method is developed to be based on quantitative quenching effect of two antihypertensive drugs on Eosin Y's native fluorescence which was achieved by developing binary complexes between each of the cited drugs in an acidic environment using acetate buffer (pH 4.4) with Eosin Y. Fluorescence quenching was recorded at 544 nm after excitation at 425 nm. For AML and PER, calibration curves were obtained over the range of 0.3–3.0 µg/mL and 0.2–2.0 µg/mL, respectively, with correlation coefficients of 0.9993 and 0.9995, respectively. The developed method was validated according to ICH guidelines. The proposed spectrofluorimetric method is regarded new and sensitive. As a result, the proposed method might be used to estimate the quality of the cited drugs in their pharmaceutical formulations and biological fluid.

First-order derivative synchronous spectrofluorimetric determination of two antihypertensive drugs, metolazone and valsartan, in pharmaceutical and biological matrices

In this study, a facile, rapid, and sensitive spectrofluorimetric method was evolved to analyse two antihypertensive drugs, namely, metolazone (MTZ) and valsartan (VST), in pharmaceutical and biological matrices. Both analytes exhibited intrinsic fluorescence activities which were significantly affected by environmental factors such as pH and solvent systems. However, simultaneous determination of MTZ and VST by conventional spectrofluorometry cannot be achieved simply because of the strong overlap between their fluorescence spectra. Thus, a combination of derivative and synchronous spectrofluorometry was conducted to overcome this dilemma. The proposed method relies on measurement of the first-order derivative of synchronous fluorescence intensity of the studied drugs at Δλ = 160 nm using 0.1 M acetic acid as the optimum solvent. The amplitudes of the first derivative synchronous fluorescence spectra of MTZ and VST were recorded at 236.0 nm (zero-crossing point of VST) and at 262.8 nm (zero-crossing point of MTZ) for simultaneous analysis of MTZ and VST, respectively. The fluorescent method was optimized efficiently to get the maximum selectivity and sensitivity by investigating different solvents, different buffer pHs, and different surfactants. The highest sensitivity and selectivity were achieved when 0.1 M acetic acid was used as a solvent. The method showed a linear concentration range of 10.0-100.0 ng mL^-1 and a limit of detection of <3.0 ng mL^-1 for each analyte. Statistical data analysis confirmed that no significant difference between the proposed spectrofluorometric method and the reference methods. The validity of the proposed spectrofluorometric method approved its suitability for quality control work. The proposed spectrofluorometric method was applied to assay the studied drugs in pharmaceutical dosage and in biological matrices with acceptable %recoveries and small RSD values.