A convenient method for determination of quizalofop-p-ethyl based on the fluorescence quenching of eosin Y in the presence of Pd(II)

Author(s):  
Huan Wu ◽  
Yanmei Zhao ◽  
Xuanping Tan ◽  
Xiaoqing Zeng ◽  
Yuan Guo ◽  
...  
2016 ◽  
Vol 14 (1) ◽  
pp. 258-266 ◽  
Author(s):  
Sayed M Derayea ◽  
Mahmoud A Omar ◽  
Mohamed Aboel-Kasem Abdel-Lateef ◽  
Ahmed I. Hassan

AbstractA simple, rapid, sensitive and economic spectrofluorimetric method has been developed and validated for determination of some β-adrenergic blocking agents namely; betaxolol hydrochloride (BTX), carvedilol (CAR), labetalol hydrochloride (LBT), nebivolol hydrochloride (NEB) and propranolol hydrochloride (PRO). The method is based on the quenching effect of the cited drugs on the fluorescence intensity of eosin Y at pH 3.4 (acetate buffer). The fluorescence quenching is due to the formation of an ion-pair complex and was measured without extraction at 545 nm (λex. 301.5 nm). The factors affecting the formation of the ion-pair complex were carefully studied and optimized. Under the optimal conditions, the linear ranges for the relationship between the fluorescence quenching value and the concentration of the investigated drugs were 100-2500, 150-2500 and 50-2250 ng mL-1 for (BTX, CAR), (LBT, NEB) and (PRO) respectively. The method was validated according to ICH guidelines and was applied for determination of the cited drugs in pharmaceutical dosage forms with excellent recoveries. In addition, content uniformity testing of some commercial dosage forms was checked by the proposed method.


Author(s):  
Mahmoud A. Omar ◽  
Amal B. Ahmed ◽  
Nada S. Abdelwahab ◽  
Maha M. Abdelrahman ◽  
Sayed M. Derayea

2010 ◽  
Vol 20 (3) ◽  
pp. 733-738 ◽  
Author(s):  
Lihong Yu ◽  
Zhongfang Liu ◽  
Xiaoli Hu ◽  
Ling Kong ◽  
Shaopu Liu

2003 ◽  
Vol 8 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Birgit Heltweg ◽  
Manfred Jung

Histone deacetylases (HDACs) are important regulators of transcription, and their inhibitors are a promising class of anticancer agents. The methods for the determination of HDAC activity and its inhibition that are currently available suffer from various drawbacks, such as animal testing, radioactive substrates, or limited throughput. Therefore, a fast nonisotopic method for the measurement of HDAC activity is highly desirable. The authors present such an assay that relies on the fluorescent HDAC substrate developed previously in their group. After incubation of the substrate with the enzyme, a derivatization leads to efficient fluorescence quenching in the deacetylated metabolite. Thus, only the fluorescence emitted by the remaining substrate is detected, which allows for a convenient detection of HDAC activity in a homogeneous format that can be performed on multiwell plate readers. This procedure, called HDASH (histone deacetylase assay—homogeneous), should be a valuable tool in transcriptional research and especially drug discovery. ( Journal of Biomolecular Screening 2003:89-95)


2014 ◽  
Vol 47 (16) ◽  
pp. 2740-2746
Author(s):  
Heng Xin Zhao ◽  
Ming Luo ◽  
Li Xin Mo ◽  
Liang Cheng ◽  
Zheng Ma ◽  
...  

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