scholarly journals Application of the First Derivative Absorption Spectrum-Shift-Length Method to the Simultaneous Determination of Binary Mixture.

1992 ◽  
Vol 40 (10) ◽  
pp. 2817-2821 ◽  
Author(s):  
Kiyoshi SHIMIZU ◽  
Yoshinori MOTOYAMA ◽  
Motoharu IWATSURU
2021 ◽  
Vol 12 (9) ◽  
pp. 27-32
Author(s):  
Shah Esha Bhavin ◽  
Gajjar Anuradha

The application of the ratio spectra derivative spectrophotometry to the simultaneous determination of Paracetamol (PCM) and Tapentadol (TAP) in combined pharmaceutical tablets is presented. The spectrophotometric procedure is based on the use of the first derivative of the ratio spectra obtained by dividing the absorption spectrum of the binary mixtures by a standard spectrum of one of the compounds. The first derivative amplitudes were measured at 220 and 232 nm for the assay of TAP and PCM, respectively. Calibration graphs were established for 1-5 μg mL-1 for TAP and 6.5-32.5 μg mL-1 for PCM in binary mixture. The detection limits for TAP and PCM were found 0.098 and 0.595 μg mL-1, respectively, while the quantification limits were 0.298 μg mL-1 for TAP and 1.805 μg/ml for PCM. The relative standard deviations were found to be less than 2%, indicating reasonable repeatability of both methods. The proposed methods were hence validated as per ICH guidelines and successfully applied to the determination of these drugs in commercial tablets.


2011 ◽  
Vol 6 ◽  
pp. ACI.S7282 ◽  
Author(s):  
Nashwah Gadallah Mohamed

A spectrophotometric method was developed for simultaneous determination of amlodipine (Aml) and valsartan (Val) without previous separation. In this method amlodipine in methanolic solution was determined using zero order UV spectrophotometry by measuring its absorbency at 360.5 nm without any interference from valsartan. Valsartan spectrum in zero order is totally overlapped with that of amlodipine. First, second and third derivative could not resolve the overlapped peaks. The first derivative of the ratio spectra technique was applied for the measurement of valsartan. The ratio spectrum was obtained by dividing the absorption spectrum of the mixture by that of amlodipine, so that the concentration of valsartan could be determined from the first derivative of the ratio spectrum at 290 nm. Quantification limits of amlodipine and valsartan were 10-80 μg/ml and 20-180 μg/ml respectively. The method was successfully applied for the quantitative determination of both drugs in bulk powder and pharmaceutical formulation.


2020 ◽  
Vol 16 (3) ◽  
pp. 254-261
Author(s):  
Ekram H. Mohamed ◽  
Ahmed Hamza ◽  
Aya Reda ◽  
Ola Adel ◽  
Sara Atef

Background: The ability of the normalized spectra when used as a divisor and in combination with isosbestic point to resolve complex binary or ternary mixtures, Candesartan and Hydrochlorthiazide binary mixture was taken as a model. Introduction: A green simple smart and accurate method using ethanol as a solvent namely simultaneous derivative ratio (SIDD) was applied to prove the power of normalized spectra and isosbestic point as spectrophotometric resolving tools. Methods: In the proposed SIDD method, the zero order spectra of drugs were simply manipulated using the normalized spectra of CAN as divisor to obtain the ratio and first derivative spectra in two successive steps. Firstly, the total amplitude at isosbestic point 255.4 nm of the ratio spectra of the mixture was measured representing the total actual concentration of both drugs in the mixture. Then, the first derivative of the ratio spectra was obtained to determine Hydrochlorothiazide concentration at 233 nm. While the concentration of Candesartan was determined subsequently by subtracting the Hydrochlorothiazide concentration calculated after derivatization from the total concentration of both drugs obtained at the ratio spectra before the derivatization step. Results: The SIDD was successfully applied for simultaneous determination of both drugs in their pure form or in their binary mixture either in synthetic prepared mixtures or in combined dosage form the adopted method was validated according to the ICH guidelines and the results were found to be within the acceptable limits. Conclusion: The adopted method highlighted the important role of normalized spectrum when used as a divisor in addition to the importance of isosbestic point to resolve severely overlapped spectra. All the measurements were carried using ethanol which is considered one of the greenest solvents making the method an environmentally friendly one. the adopted method was validated according to the ICH guidelines and the results were found to be within the acceptable limits.


2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Shilan A. Omer ◽  
Nabil A. Fakhre

In this study, three simple and accurate spectrophotometric methods for simultaneous determination of pyriproxyfen and chlorothalonil residues in cucumbers and cabbages grown in experimental greenhouse were studied. The first method was based on the zero-crossing technique measurement for first and second derivative spectrophotometry. The second method was based on the first derivative of the ratio spectra. However, the third method was based on mean centering of ratio spectra. These procedures lack any previous separation steps. The calibration curves for three spectrophotometric methods are linear in the concentration range of 1–30 μg·mL−1 and 0.5–7 μg·mL−1 for pyriproxyfen and chlorothalonil successively. The recoveries ranged from 82.12–97.40% for pyriproxyfen and 81.51–97.04% for chlorothalonil with relative standard deviations less than 4.95% and 5.45% in all instances for pyriproxyfen and chlorothalonil, respectively. The results obtained from the proposed methods were compared statistically by using one-way ANOVA, and the results revealed there were no significant differences between ratio spectra and mean centering methods with the zero-crossing technique. The proposed methods are successfully applied for the simultaneous estimation of the residue of both pesticides in cucumber and cabbage samples.


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