Novel spectrophotometric methods for simultaneous determination of timolol and dorzolamide in their binary mixture

Lotfy, Hayam M.; Hegazy, Maha A.; Rezk, Mamdouh R.; Omran, Yasmin Rostom

doi:10.1016/j.saa.2014.02.005

Cited by 83 publications

(31 citation statements)

References 34 publications

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“…This method was based on the same principle as the absorption factor method [34][35][36][37]. The method has mainly depended on the presence of an isoabsorptive point in the zero order absorption spectra of the drugs (λiso 267 nm) where the drugs have equal absorptivities at this point.…”

Section: Absorbance Subtraction Methods (As)mentioning

confidence: 99%

Simultaneous determination of levonorgestrel and ethinyl estradiol in combined dosage form utilizing spectrophotometric methods and high performance thin layer chromatographic method on nanosilica gel plates

et al. 2017

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Simultaneous quantification of levonorgestrel (LEV) and ethinyl estradiol (EE) was performed utilizing five different spectrophotometric methods and a high performance thin layer chromatographic method (HPTLC). The applied spectrophotometric methods were based on either ratio spectra namely; ratio difference, ratio subtraction and derivative ratio or the presence of isosbestic point specifically; absorbance subtraction and amplitude modulation. The proposed methods had the ability to resolve the overlapped spectra of the drugs with a linear relationship in the concentration range 1-65 µg/mL and 1-95 µg/mL for LEV and EE, respectively. The developed HPTLC method has revealed a good separation of the drugs upon utilizing Nano Silica Gel on TLC plates with fluorescent indicator 254 nm glass plates as the stationary phase and chloroform: methanol (99:1, v:v) as the mobile phase. The proposed HPTLC method has shown high sensitivity, where the linearity range was 0.02-3.00 µg/band and 0.5-20.0 µg/band, for LEV and EE, respectively. The proposed methods were successfully applied for the analysis of laboratory prepared mixtures as well as combined dosage form. Validation for all methods was conducted in compliance with the ICH guidelines proving the methods to be selective, linear, precise and accurate. The proposed methods were statistically compared with the pharmacopoeial method, where the obtained results showed no significant difference regarding accuracy and precision.

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Section: Absorbance Subtraction Methods (As)mentioning

confidence: 99%

Simultaneous determination of levonorgestrel and ethinyl estradiol in combined dosage form utilizing spectrophotometric methods and high performance thin layer chromatographic method on nanosilica gel plates

et al. 2017

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“…The developed area under the curve ("AUC"), modified absorption factor method (MAFM) and modified amplitude center method (MACM) are firstly introduced for resolving ternary mixture of overlapping spectra. The newly introduced analytical methods are a modification of the recently developed spectrophotometric methods, [11][12][13][14][15][16][17][18][19][20][21][22] while the same author published a PLS chemometric method for analysis of the same ternary mixture since 2012.…”

Section: )mentioning

confidence: 99%

“…The modification was carried out in order to apply the previous method to ternary or more complicated mixtures. Moreover, this method has advantage over the amplitude factor method, [17][18][19] in that it does not need any derivatization or division steps, hence signal to noise ratio is enhanced.…”

Section: )mentioning

confidence: 99%

Three New Methods for Resolving Ternary Mixture with Overlapping Spectra: Comparative Study

Abdelwahab

Mohamed

2017

CHEMICAL & PHARMACEUTICAL BULLETIN

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In this study three new spectrophotometric methods have been developed and validated for simultaneous determination of ternary mixture of metronidazole (MET), diloxanide (DLX) and mebeverine HCl (MEB) without prior separation steps. The newly introduced methods consisted of several steps utilizing either zero order or ratio spectra without the need for derivatization steps. The developed methods are called area under the curve ("AUC"), modified absorption factor (MAFM) and modified amplitude center (MACM) spectrophotometric methods. Selectivity and validity of the methods were checked by using different synthetic mixtures and by analysis of their combined dosage form where low standard deviation values and good percentage recoveries were obtained. Additionally, methods linearity, accuracy and precision were determined following United States Pharmacopoeia (USP) recommendations. The obtained results were found to agree with the reported ones when they were statistically compared using One Way ANOVA test. These methods are easily applied during drug quality control studies and in laboratories lacking the facilities of chromatographic methods of analysis. Data manipulation steps are very simple, hence these methods can be considered as time and money saving methods comparing to chromatographic methods of analysis.

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“…1b), is used as an antihypertensive and an antiglaucoma agent. Literature survey revealed that few methods have been reported for the determination of TIM in pharmaceutical preparations such as spectrophotometric methods [28][29][30]. Here, also, derivative ultraviolet [31,32], high-performance liquid chromatography [33,34], liquid chromatography [35], chemiluminescence [36] and electrophoresis [37].…”

Section: Introductionmentioning

confidence: 99%

Direct Spectrophotometric Determination of Atenolol and Timolol Anti-Hypertensive Drugs

El‐Didamony

Moustafa

2017

Int J Pharm Pharm Sci

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Objective: Direct and sensitive spectrophotometric method is described for the quantitative determination of some anti-hypertensive drugs such as atenolol (ATN) and timolol (TIM) in pure forms as well as in their dosage forms. Methods:The proposed method is based on the redox reaction between the selected drugs and KMnO4 in alkaline medium. The method involves treating the aqueous solution of the selected drugs with KMnO4 in alkaline medium and measuring the bluish-green product at 610 nm. The different experimental parameters affecting the development and stability of the color were carefully studied and optimized. Results:The fixed-time method is adopted for constructing the calibration curves, which were found to be linear over the concentration ranges of 2.0-14 µg/ml and 2.0-28 µg/ml for ATN and TIM, respectively. The determination of the studied drugs by initial rate, variable time and rate constant method was workable with the calibration equations obtained but the fixed time method has been found to be more applicable. Conclusion:The applicability of the proposed method was demonstrated by the determination of the selected drugs in both pure and in commercial dosage forms and has met the validation requirements.

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Novel spectrophotometric methods for simultaneous determination of timolol and dorzolamide in their binary mixture

Cited by 83 publications

References 34 publications

Simultaneous determination of levonorgestrel and ethinyl estradiol in combined dosage form utilizing spectrophotometric methods and high performance thin layer chromatographic method on nanosilica gel plates

Simultaneous determination of levonorgestrel and ethinyl estradiol in combined dosage form utilizing spectrophotometric methods and high performance thin layer chromatographic method on nanosilica gel plates

Three New Methods for Resolving Ternary Mixture with Overlapping Spectra: Comparative Study

Direct Spectrophotometric Determination of Atenolol and Timolol Anti-Hypertensive Drugs

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