Determination of major chlorophyll degradation products

1997 ◽  
Vol 204 (5) ◽  
pp. 345-350 ◽  
Author(s):  
Thomas J. Mangos ◽  
R. G. Berger
Keyword(s):  
Degradation Products ◽  
Chlorophyll Degradation

SEDIMENTARY CHLOROPHYLL DETERMINATION AS A PALEOBOTANICAL METHOD

1955 ◽  
Vol 33 (4) ◽  
pp. 304-313 ◽  
Author(s):  
J. R. Vallentyne
Keyword(s):  
Chlorophyll Content ◽  
Chlorophyll A ◽  
Light Absorption ◽  
Quantitative Method ◽  
Degradation Products ◽  
Wave Length ◽  
Chlorophyll Degradation ◽  
Plant Tissues ◽  
Sediment Profiles

Chlorophyll degradation products which can be extracted from sediments with 90% acetone and which show maximal light absorption in the red end of the spectrum at a wave length of 667 mμ (90% acetone as the solvent) are here collectively defined as sedimentary chlorophyll. A quantitative method is described for the determination of sedimentary chlorophyll. Results from six different sediment profiles are presented. The nature of sedimentary chlorophyll is unknown, except that it consists of at least three chlorophyll degradation products. Sedimentary chlorophyll has been found in samples aged up to 11,000 years. In any one profile the fluctuations in sedimentary chlorophyll content may be used to infer changes in the abundance of chlorophyll-bearing plant tissues, but only with the greatest caution.

scholarly journals Determination of Chlorophyll Degradation Products in Chlorophyll Color Preparations

1997 ◽  
Vol 38 (3) ◽  
pp. 155-160_1 ◽  
Author(s):  
Keiko HIRATA ◽  
Masako HIROKADO ◽  
Yoko UEMATSU ◽  
Yuki SADAMASU ◽  
Kazuo YASUDA ◽  
...  
Keyword(s):  
Degradation Products ◽  
Chlorophyll Degradation

Is Quantitative Determination of Fibrin(ogen) Degradation Products and Thrombin-Antithrombin III Complexes Useful to Diagnose Deep Venous Thrombosis in Outpatients?

1989 ◽  
Vol 62 (04) ◽  
pp. 1043-1045 ◽  
Author(s):  
Paul F M M van Bergen ◽  
Eduard A R Knot ◽  
Jan J C Jonker ◽  
Auke C de Boer ◽  
Moniek P M de Maat
Keyword(s):  
Quantitative Determination ◽  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Antithrombin Iii ◽  
Degradation Products ◽  
Family Doctor ◽  
Diagnostic Value ◽  
Impedance Plethysmography ◽  
Fibrin Degradation Products

SummaryWe studied the diagnostic value of recently introduced ELISA’s for the determination of thrombin-antithrombin III (TAT) complexes, fibrin degradation products (FbDP), fibrinogen degradation products (FgDP) and total degradation products (TDP) for deep venous thrombosis (DVT) in plasma of 239 consecutive outpatients, suspected for DVT by their family doctor. DVT was confirmed by impedance plethysmography in 60 patients. Using the 95th percentile range of 42 healthy volunteers the sensitivity for the detection of DVT was: 37% for TAT, 95% for TDP, 92% for FbDP and 90% for FgDP. Specificity was: 88% for TAT, 16% for TDP, 20% for FbDP and 25% for FgDP.We conclude that these assays are of little value in the diagnosis of DVT in outpatients.

Stability Indicating Liquid Chromatographic Method for the Determination of Fenofibrate and its Application to Kinetic Studies

2013 ◽  
Vol 5 (4) ◽  
pp. 1866-1874
Author(s):  
K. Srinivasa Rao ◽  
Keshar N K ◽  
N Jena ◽  
M.E.B Rao ◽  
A K Patnaik
Keyword(s):  
Degradation Products ◽  
Kinetic Studies ◽  
Pharmaceutical Formulations ◽  
Assay Method ◽  
Pharmaceutical Dosage Form ◽  
Stability Indicating ◽  
Zero Order Kinetics ◽  
Relative Standard ◽  
Liquid Chromatographic

A stability-indicating LC assay method was developed for the quantitative determination of fenofibrate (FFB) in pharmaceutical dosage form in the presence of its degradation products and kinetic determinations were evaluated in acidic, alkaline and peroxide degradation conditions. Chromatographic separation was achieved by use of Zorbax C18 column (250 × 4.0 mm, 5 μm). The mobile phase was established by mixing phosphate buffer (pH adjusted 3 with phosphoric acid) and acetonitrile (30:70 v/v). FFB degraded in acidic, alkaline and hydrogen peroxide conditions, while it was more stable in thermal and photolytic conditions. The described method was linear over a range of 1.0-500 μg/ml for determination of FFB (r= 0.9999). The precision was demonstrated by relative standard deviation (RSD) of intra-day (RSD= 0.56– 0.91) and inter-day studies (RSD= 1.47). The mean recovery was found to be 100.01%. The acid and alkaline degradations of FFB in 1M HCl and 1M NaOH solutions showed an apparent zero-order kinetics with rate constants 0.0736 and 0.0698  min−1 respectively and the peroxide degradation with 5% H2O2 demonstrated an apparent first-order kinetics with rate constant k = 0.0202 per min. The t1/2, t90   values are also determined for all the kinetic studies. The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of FFB in pharmaceutical formulations.  

Recent Applications of High Performance Thin Layer Chromatography and Derivative Spectrophotometry in Pharmaceutical Analysis

2020 ◽  
Vol 16 (6) ◽  
pp. 671-689
Author(s):  
Marcin Gackowski ◽  
Marcin Koba ◽  
Katarzyna Mądra-Gackowska ◽  
Piotr Kośliński ◽  
Stefan Kruszewski
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Pharmaceutical Analysis ◽  
High Performance ◽  
Degradation Products ◽  
Derivative Spectrophotometry ◽  
Accuracy And Precision ◽  
Post Marketing ◽  
Layer Chromatography

At present, no one can imagine drug development, marketing and post-marketing without rigorous quality control at each stage. Only modern, selective, accurate and precise analytical methods for determination of active compounds, their degradation products and stability studies are able to assure the appropriate amount and purity of drugs administered every day to millions of patients all over the world. For routine control of drugs simple, economic, rapid and reliable methods are desirable. The major focus of current scrutiny is placed on high-performance thin layer chromatography and derivative spectrophotometry methods, which fulfill routine drug estimation’s expectations [1-4]. The present paper reveals state-of-the-art and possible applications of those methods in pharmaceutical analysis between 2010 and 2018. The review shows advantages of high-performance thin layer chromatography and derivative spectrophotometry, including accuracy and precision comparable to more expensive and time-consuming methods as well as additional fields of possible applications, which contribute to resolving many analytical problems in everyday laboratory practice.

A Versatile Stability-indicating Liquid Chromatographic Method for the Simultaneous Determination of Atenolol, Hydrochlorothiazide and Chlorthalidone

2020 ◽  
Vol 16 (8) ◽  
pp. 1037-1051
Author(s):  
Ehab Farouk Elkady ◽  
Marwa Ahmed Fouad ◽  
Abdulgabar A. Ezzy Faquih
Keyword(s):  
Quality Control ◽  
Chromatographic Method ◽  
Degradation Products ◽  
Pharmaceutical Dosage Forms ◽  
Potassium Dihydrogen ◽  
Ich Guidelines ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic ◽  
Potassium Dihydrogen Orthophosphate

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.

ICH/FDA Guidelines-Compliant Validated Stability-Indicating HPLC-UV Method for the Determination of Axitinib in Bulk and Dosage Forms

2020 ◽  
Vol 16 (8) ◽  
pp. 1106-1112
Author(s):  
Ibrahim A. Darwish ◽  
Nasr Y. Khalil ◽  
Mohammad AlZeer
Keyword(s):  
High Performance ◽  
Kinase Inhibitor ◽  
Degradation Products ◽  
Internal Standard ◽  
Dosage Forms ◽  
Uv Detector ◽  
Stability Indicating ◽  
Therapeutic Benefits ◽  
Relative Standard

Background: Axitinib (AXT) is a member of the new generation of the kinase inhibitor indicated for the treatment of advanced renal cell carcinoma. Its therapeutic benefits depend on assuring the good-quality of its dosage forms in terms of content and stability of the pharmaceutically active ingredient. Objective: This study was devoted to the development of a simple, sensitive and accurate stabilityindicating high-performance liquid chromatographic method with ultraviolet detection (HPLC-UV) for the determination of AXT in its bulk and dosage forms. Methods: Waters HPLC system was used. The chromatographic separation of AXT, internal standard (olaparib), and degradation products were performed on the Nucleosil CN column (250 × 4.6 mm, 5 μm). The mobile phase consisted of water:acetonitrile:methanol (40:40:20, v/v/v) with a flow rate of 1 ml/min, and the UV detector was set at 225 nm. AXT was subjected to different accelerated stress conditions and the degradation products, when any, were completely resolved from the intact AXT. Results: The method was linear (r = 0.9998) in the concentration range of 5-50 μg/ml. The limits of detection and quantitation were 0.85 and 2.57 μg/ml, respectively. The accuracy of the method, measured as recovery, was in the range of 98.0-103.6% with relative standard deviations in the range of 0.06-3.43%. The results of stability testing revealed that AXT was mostly stable in neutral and oxidative conditions; however, it was unstable in alkaline and acidic conditions. The kinetics of degradation were studied, and the kinetic rate constants were determined. The proposed method was successfully applied for the determination of AXT in bulk drug and dosage forms. Conclusions: A stability-indicating HPLC-UV method was developed and validated for assessing AXT stability in its bulk and dosage forms. The method met the regulatory requirements of the International Conference on Harmonization (ICH) and the Food and Drug Administration (FDA). The results demonstrated that the method would have great value when applied in quality control and stability studies for AXT.

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