Petroleum and related products. Determination of the hydrolytic stability of fire-resistant phosphate ester fluids

2005 ◽  
Keyword(s):  
Hydrolytic Stability ◽  
Phosphate Ester

Micro-Determination of p-Hydroxybenzoic Esters in Pharmaceuticals and Cosmetics

1977 ◽  
Vol 60 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Emil Weisenberg ◽  
Baruch Gershon ◽  
Judith Schoenberg
Keyword(s):  
Liquid Chromatography ◽  
Phosphate Ester ◽  
Specific Method ◽  
Gas Liquid Chromatography ◽  
Direct Extraction ◽  
Flame Photometric Detector ◽  
Phenol Derivatives ◽  
Margin Of Error ◽  
Diethyl Phosphate

Abstract A rapid and specific method is described for the determination of microamounts of methyl, propyl, and butyl p-hydroxybenzoic esters (parabens) in pharmaceuticals and cosmetics. The method involves the direct extraction of parabens into benzene or chloroform followed by derivatization with phosphorochloridate. The diethyl phosphate ester derivatives are cleaned up on a Florisil minicolumn and finally measured by gas-liquid chromatography on 5% OV-210 on Gas-Chrom Q. A flame photometric detector or a KCl thermionic detector may be used. The concentration response was linear up to 40 ng parabens. The reproducibility and margin of error were tested with fortified samples. This method may be applied to the estimation of other phenol derivatives.

Aryl-Substituted and Benzo-Annulated CycloSal-Derivatives of 2′,3′-Dideoxy-2′,3′-Didehydrothymidine Monophosphate — Correlation of Structure, Hydrolysis Properties and Anti-HIV Activity

2002 ◽  
Vol 13 (2) ◽  
pp. 129-141 ◽  
Author(s):  
Christian Ducho ◽  
Jan Balzarini ◽  
Lieve Naesens ◽  
Erik De Clercq ◽  
Chris Meier
Keyword(s):  
Antiviral Activity ◽  
Degradation Products ◽  
Hydrolytic Stability ◽  
Substitution Pattern ◽  
Cell Extracts ◽  
Hydrolysis Process ◽  
The Stability ◽  
Anti Hiv

The synthesis of phenyl-substituted and benzo-annulated cycloSal phosphate triesters of the nucleoside analogue 2′,3′-dideoxy-2′,3′-didehydrothymidine (d4T, Zerit™) as lipophilic, membrane-soluble pronucleotides is described. The cycloSal moiety was introduced by using cyclic chlorophosphite agents prepared from phenyl-substituted saligenin derivatives and orthohydroxymethylated naphthols, respectively. Hydrolysis studies (HPLC analysis) of the triesters 2, 3 showed a range of hydrolytic stability from 1.4 h up to 5.1 h and the stability could be correlated with the substitution pattern in the cycloSal moiety. A slight decrease of their stability was observed, if phenyl-substituted derivatives were hydrolyzed in human CEM/O cell extracts. D4T and thymine, possible products of enzymatic cleavage of the pronucleotides, were not detected in the cell extracts. A further investigation of the hydrolysis process was performed by 31P-NMR spectroscopy. This technique allowed a precise monitoring of the degradation products and the exact determination of the product ratio. Finally, the newly synthesized compounds were tested concerning their antiviral activity against HIV in vitro. A strong correlation of the hydrolysis properties and the antiviral activity was found. 3-phenyl- cycloSal-d4TMP showed a threefold increase in its anti-HIV-1 activity and retained full activity in thymidine kinase (TK) deficient cells, indicative of a successful TK-bypass.

Hydrolytic stability of water-soluble spruce O-acetyl galactoglucomannans

Holzforschung ◽  
2009 ◽  
Vol 63 (1) ◽  
Author(s):  
Chunlin Xu ◽  
Andrey Pranovich ◽  
Jarl Hemming ◽  
Bjarne Holmbom ◽  
Simone Albrecht ◽  
...  
Keyword(s):  
Food Processing ◽  
Molar Mass ◽  
Hydrolytic Stability ◽  
Water Soluble ◽  
Average Molar Mass ◽  
Acidic Conditions ◽  
The Stability ◽  
Stability Of Water ◽  
Hydrolysis Of

Abstract Water-soluble native O-acetyl galactoglucomannan (GGM) from spruce is a polysaccharide that can be produced in an industrial scale. To develop GGM applications, information is needed on its stability, particularly under acidic conditions. Therefore, acid hydrolysis of spruce GGM was investigated at various pH levels and temperatures. The results allow an estimation of the stability of GGM under food processing conditions and in biological systems. Determination of the average molar mass demonstrated that spruce GGM was stable at pH 1 and 37°C, as well as at pH 3 and 70°C. GGM was hydrolysed at pH 1 and 90°C. GGM oligomers and monomers were detected after degradation. Some of the oligomers contained O-acetyl groups. Monosaccharides were the predominant products in the hydrolysates after treatment at pH 1 and 90°C for 48 h. Pentoses, present in GGM samples as impurities, were released more easily than GGM hexoses. Glucose was more difficult to release than mannose. Traces of 6-deoxy-mannose and levoglucosan were found in the hydrolysates, indicating further degradation of hydrolysed monosaccharides.

Development and Validation of a Liquid Chromatographic Method for Aroylhydrazones at Hydrolytic Conditions

2019 ◽  
Vol 16 ◽  
Author(s):  
Vania Maslarska ◽  
Stanislav Bozhanov ◽  
Stefka Ivanova ◽  
Violina T. Angelova
Keyword(s):  
High Performance ◽  
Hydrolytic Stability ◽  
Aqueous Media ◽  
Antimycobacterial Activity ◽  
Pharmaceutical Formulations ◽  
Pseudo First Order Reaction ◽  
Development And Validation ◽  
Liquid Chromatographic ◽  
Hydrolysis Of

Aims: The indole-containing aroylhydrazone derivatives 3a-c with potent antimycobacterial activity against a referent strain M. tuberculosis H37Rv and low cytotoxicity were evaluated for their stability via the precise and accurate HPLC analytical method in aqueous media of different pH (2.0, 7.0, 9.0 and 12.0). Objective: The study describes the development and validation of a simple and reliable HPLC-UV procedure for the determination of aroylhydrazone derivatives and their hydrolytic stability. Additionally, to recognize if hydrolysis leads to generating undesired products, the degradation processes were identified. Method: The separation was achieved with a LiChrosorb®RP-18 (250 x 4.6 mm) column, at ambient temperature with isocratic mode with mobile phase containing mixture of component A (acetonitrile) and component B (0.001M NaH2PO4, with 5 mM 1-heptane sulfonic acid sodium salt, adjusted to pH 3.0) in a ratio 60:40 (v/v). The flow rate was 1.0 ml/min and the eluent was monitored at 297 nm. The proposed method was validated as per ICH guidelines. Result: The obtained results showed that the compounds were sensitive to hydrolytic decomposition in aqueous media, resulting in the splitting of the hydrazone bond. Rapid hydrolysis of substances was observed in the acid medium. The elevated temperature significantly accelerated the hydrolytic reaction. Relatively slow hydrolysis of 3a-c was observed in a neutral solution and aqueous solutions buffered to pH 9. The hydrolysis of 3a-c in neutral, alkaline and strong alkaline medium followed the pseudo-first-order reaction rate and showed a linear dependence of lnC versus time. Conclusion: A validated high-performance liquid chromatographic assay for the determination of the hydrolytic stability of a series of aroylhydrazones was developed and optimized for the first time. The methods devised are successfully applicable to the development of pharmaceutical formulations.

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