Proposal for the updating of the ISO 29 841 liquid chromatographic method for the determination of chlorophyll a and a’ degradation products in virgin olive oil

Author(s):  
Evmorfia Kritiktsi ◽  
Maria Z. Tsimidou ◽  
Nikolaos Nenadis
2020 ◽  
Vol 16 (8) ◽  
pp. 1037-1051
Author(s):  
Ehab Farouk Elkady ◽  
Marwa Ahmed Fouad ◽  
Abdulgabar A. Ezzy Faquih

Background: Atenolol is a selective beta 1 blocker that can be used alone or in combination with hydrochlorothiazide or with chlorthalidone for the treatment of hypertension and prevention from a heart attack. Objective: The main target of this work was to improve modern, easy, accurate and selective liquid chromatographic method (RP-HPLC) for the determination of these drugs in the presence of their degradation products. These methods can be used as analytical gadgets in quality control laboratories for a routine examination. Methods: In this method, the separation was accomplished through an Inertsil® ODS-3V C18 column (250 mm x 4.6 mm, 5 μm), the mobile phase used was 25 mM aqueous potassium dihydrogen orthophosphate solution adjusted to pH 6.8 by using 0.1M sodium hydroxide and acetonitrile (77 : 23, v/v), the flow rate used was 1 ml/min and detection was achieved at 235 nm using UV. Results: All peaks were sharp and well separated, the retention times were atenolol degradation (ATN Deg.) 2.311 min, atenolol (ATN) 2.580 min, hydrochlorothiazide degradation (HCT Deg.) 5.890 min, hydrochlorothiazide (HCT) 7.016 min, chlorthalidone degradation CTD Deg 8.018 min and chlorthalidone (CTD) 14.972 min. Linearity was obtained and the range of concentrations was 20- 160 μg/ml for atenolol, 10-80 μg/ml for hydrochlorothiazide and 10-80 μg/ml for chlorthalidone. According to ICH guidelines, method validation was accomplished, these methods include linearity, accuracy, selectivity, precision and robustness. Conclusion: The optimized method demonstrated to be specific, robust and accurate for the quality control of the cited drugs in pharmaceutical dosage forms.


1996 ◽  
Vol 79 (3) ◽  
pp. 636-639 ◽  
Author(s):  
William H Doub ◽  
Don D Ruhl ◽  
Brad Hart ◽  
Paul R Mehelic ◽  
Larry K Revelle

Abstract A liquid chromatographic method was developed for determination of chlorhexidine and its degradation products in unformulated drug substance. A nonlinear gradient from 80% 0.1 M ammonium acetate buffer, pH 5.0, to 20% buffer over 90 min (balance is acetonitrile) is applied to a 3 μm octadecylsilane bonded-phase column. The drug and some of its degradation products are determined at 230 nm. Of 11 previously identified degradation products, 9 are determined with good precision (relative standard deviation of peak area is <2%).


1992 ◽  
Vol 75 (1) ◽  
pp. 62-65 ◽  
Author(s):  
R Khazanchi ◽  
S Walia ◽  
S K Handa

Abstract A reversed-phase liquid chromatographic method has been developed for the determination of fenamiphos and the metabolites fenamiphos sulfoxide, fenamiphos sulfone, 3-methyl-4-(methylthlo)- phenol, and 3-methyl-4-(methylsulflnyl)phenol. Trace quantities of the nematlclde and Its metabolites In soil can be determined simultaneously. The limit of detection of the method was 5 ppm. Recoveries of fenamiphos and Its degradation products at fortification levels of 25,50, and 100 ppm ranged from 99.2 to 100.8%. Standard deviations ranged from 0.29 to 0.70 ppm.


2005 ◽  
Vol 88 (6) ◽  
pp. 1661-1665 ◽  
Author(s):  
Tushar N Mehta ◽  
Gunta Subbaiah ◽  
Kilambi Pundarikakshudu

Abstract A simple, fast, specific, stability-indicating, and precise reversed-phase liquid chromatographic method was developed for the determination of Cefdinir in its different dosage forms, i.e., capsules and suspensions. The method was developed and optimized by analyzing the placebo preparation, formulations, and degraded samples of the drug substance according to the International Conference on Harmonization. The proposed method can successfully separate the drug from degradation products formed under stress conditions along with pharmaceutical ingredients such as preservatives. The developed method was used successfully to determine Cefdinir in capsules and Insta-use suspensions. The developed method was found to be linear for a concentration range of 6–14 μg/mL. Average recoveries obtained with the method were 99.3 ± 0.4 and 99.6 ± 0.4% for Insta-use suspensions and capsules, respectively. The method was shown to be specific, precise, and robust.


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