Total Synthesis of C-8 Hydroxyl Substituted Lomefloxacin as the Photolysis Impurity

2021 ◽  
Vol 18 ◽  
Author(s):  
Si Chen ◽  
Ying Wang ◽  
Xiao Yuan ◽  
Laiyou Wang
Keyword(s):  
Total Synthesis ◽  
Solid Phase ◽  
Active Pharmaceutical Ingredient ◽  
Ethyl Acrylate ◽  
Phase Extraction ◽  
Initial Reactant ◽  
Photochemical Decomposition ◽  
The Stability ◽  
Consistency Evaluation ◽  
Methoxybenzoic Acid

Objective: Photochemical decomposition of lomefloxacin (Lom) is supposed to result in the generation of C-8 substituted impurity and accompanied fluoride. The existence and amount of C-8 hydroxyl substituted Lom could be proposed as the marker to the stability and process consistency. The specific C-8 hydroxyl substituent impurity (1-ethyl-6-fluoro-8-hydroxy-7-(3-methylpiperazin-1-yl )-4-oxo-1,4-dihydroquinoline-3-carboxylic acid) was designed and synthesized to be available. Method: 2,4,5-trifluoro-3-methoxybenzoic acid as the initial reactant was subjected to a series of seven-step reactions, such as acylation, condensation with trans N,N-dimethylamino ethyl acrylate, N-ethylation, cyclization, hydrolysis, condensation with piperazine and acidification. The resultant substance was then purified using HPLC and C18 solid-phase extraction. The structure of C-8 hydroxyl substituted Lom was identified with 1H-NMR, 13C-NMR and HRMS spectroscopes, as well as the purity was determined by HPLC. Conclusion: C-8 hydroxyl substituted Lom was successfully synthesized and purified with purity more than 96%. This photolysis impurity offers an alternative for not only further generic Lom active pharmaceutical ingredient development involved in quality control and consistency evaluation, but also research for the mechanism underlying Lom-induced photosensitivity.

scholarly journals One-Step Synthesis of N-Succinimidyl-4-[18F]Fluorobenzoate ([18F]SFB)

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3436 ◽  
Author(s):  
Ida Nymann Petersen ◽  
Jacob Madsen ◽  
Christian Bernard Matthijs Poulie ◽  
Andreas Kjær ◽  
Matthias Manfred Herth
Keyword(s):  
Solid Phase Extraction ◽  
Total Synthesis ◽  
Radiochemical Purity ◽  
Solid Phase ◽  
Phase Extraction ◽  
One Pot ◽  
Synthesis Time ◽  
Synthesis Route ◽  
One Step

Herein, we present a one-step labeling procedure of N-succinimidyl-4-[18F]-fluorobenzoate ([18F]SFB) starting from spirocyclic iodonium ylide precursors. Precursor syntheses succeeded via a simple one-pot, two-step synthesis sequence, in yields of approximately 25%. Subsequent 18F-nucleophilic aromatic labeling was performed, and radiochemical incorporations (RCCs) from 5–35% were observed. Purification could be carried out using HPLC and subsequent solid phase extraction. Radiochemical purity (RCP) of >95% was determined. The total synthesis time, including purification and formulation, was no longer than 60 min. In comparison to the established 3-step synthesis route of [18F]SFB, this one-step approach avoids formation of volatile radioactive side-products and simplifies automatization.

scholarly journals Stability evaluation of compounded clonidine hydrochloride oral liquids based on a solid-phase extraction HPLC-UV method

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260279
Author(s):  
Daphné Coache ◽  
Mihaela Friciu ◽  
V. Gaëlle Roullin ◽  
Marianne Boulé ◽  
Jean-Marc Forest ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Phase Extraction ◽  
Quantitative Measurements ◽  
Clonidine Hydrochloride ◽  
Chemical Instabilities ◽  
The Stability ◽  
Physical And Chemical ◽  
Multiple Light Scattering

The present study aimed to assess the stability of clonidine hydrochloride oral liquids (20-μg/mL) prepared from two different generic tablets in Ora-Blend and stored in amber plastic bottles. Physical and chemical stabilities were evaluated over a period of 90 days at 25°C. Analytical challenges were overcome with the development of a new extraction procedure based on solid phase extraction to ensure efficient clonidine hydrochloride quantification. The absence of physical instabilities, evaluated by qualitative and quantitative measurements (static multiple light scattering), as well as the absence of chemical instabilities, evidenced by a stability-indicating HPLC-UV method, confirmed that a beyond-use date of 90 days was appropriate for these compounded oral liquids.

scholarly journals Stability of Pesticides on Solid-Phase Extraction Disks After Incubation at Various Temperatures and for Various Time Intervals: Interlaboratory Study

2006 ◽  
Vol 89 (4) ◽  
pp. 903-912 ◽  
Author(s):  
Jean M Cobb ◽  
John D Mattice ◽  
Scott A Senseman ◽  
Jose A Dumas ◽  
Wondi Mersie ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Water Samples ◽  
Solid Phase ◽  
Deionized Water ◽  
Interlaboratory Study ◽  
Time Interval ◽  
Phase Extraction ◽  
Time Intervals ◽  
The Stability

Abstract An interlaboratory study was conducted at 8 locations to assess the stability of pesticides on solid-phase extraction (SPE) disks after incubation at various temperatures and for various time intervals. Deionized water fortified with selected pesticides was extracted by using 2 types of SPE filtration disks (Empore C18 and Speedisk® C18XF), and after extraction, the disks were incubated at 3 temperatures (25, 40, and 55C) and for 2 time intervals (4 and 14 days). Deionized water was fortified with atrazine, carbofuran, and chlorpyrifos by all participating laboratories. In addition, some of the laboratories included 2 of the following pesticides: metolachlor, metribuzin, simazine, chlorothalonil, and malathion. Concurrently, fortified water samples were extracted with the incubated samples by using each disk type at 4 and 14 days. Pesticides had equivalent or greater stability on ≤1 of the C18 disk types, compared with storage in water. The lowest recoveries of carbofuran (6%) and chlorpyrifos (7%) were obtained at 55C after storage for 14 days in incubated water. At 55C after 14 days, the lowest recovery for atrazine was 65% obtained by using Empore disks. Pesticide-specific losses occurred on the C18 disks in this study, underlining the importance of temperature and time interval when water is extracted at remote field locations and the SPE disks containing the extracted pesticides are transported or shipped to a laboratory for elution and analysis.

Analysis of N-methylpyrrolidine in cefepime hydrochloride by ion chromatography using suppressed conductivity detection with solid-phase extraction pre-treatment

2014 ◽  
Vol 6 (4) ◽  
pp. 1248-1253 ◽  
Author(s):  
Nathanael Page ◽  
Richard Stevenson ◽  
Mark Powell
Keyword(s):  
Sample Preparation ◽  
Preparation Method ◽  
Solid Phase ◽  
Hydrolysis Product ◽  
Phase Extraction ◽  
Sample Preparation Method ◽  
Lactam Antibiotic ◽  
Suppressed Conductivity Detection ◽  
Pre Treatment ◽  
The Stability

N-Methylpyrrolidine (NMP) is the principal hydrolysis product of cefepime hydrochloride, a β-lactam antibiotic. Here we develop a sample preparation method for NMP in cefepime hydrochloride which significantly improves the stability of sample solutions.

Direct stability characterization of aconite alkaloids in different media by autosampler-mediated incubation-online solid phase extraction-LC-MS/MS

2016 ◽  
Vol 8 (8) ◽  
pp. 1942-1949 ◽  
Author(s):  
Na Zhang ◽  
Jun Li ◽  
Qingqing Song ◽  
Shepo Shi ◽  
Chun Li ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
High Performance ◽  
Solid Phase ◽  
Phase Extraction ◽  
Drug Candidates ◽  
Chromatography Tandem Mass Spectrometry ◽  
Online Solid Phase Extraction ◽  
Liquid Chromatography Tandem Mass ◽  
The Stability

An automated procedure for direct monitoring of the stability of drug candidates in different media was developed by integrating autosampler-mediated incubation, online solid phase extraction, and high performance liquid chromatography-tandem mass spectrometry (AMI-SPE-LC-MS/MS).

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

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