Tag Archives: amoxicillin

Improvements of Amoxicillin Stability in Acidic Environment

Rad I.1, Croitoru M.D.2, Gyéresi Á.2

1 “Dimitrie Cantemir” College, Tg. Mures
2 Faculty of Pharmacy, University of Medicine and Pharmacy Tg. Mures

Background: Helicobacter pylori is a gram negative bacteria responsible for a series of gastrointestinal diseases: gastric and gastroduodenal ulcers. Usually used in combinations with other drugs, amoxicillin is effective against this germ. Amoxicillin has better stability than other penicillins in solutions with pH between 4 and 7, but stability is decreased at low pH values (gastric acidity).
Aim: Our goal was to improve amoxicillin’s stability by using auxiliary substances such b-cyclodextrin (b-CD), 2-hydroxypropil-bcyclodextrin (2-HP-b-CD), magnesium glutamate and magnesium aspartate.
Methods: Influence of these excipients on amoxicillin stability was assessed at pH value of 1.2 and also in weakly alkaline environment. High pressure liquid chromatography and thin layer chromatography were used to quantitate these influences.
Results: All the studied excipients improved the stability of amoxicillin, best results being recorded when amoxicillin was associated with cyclodextrins in a mole ratio of 1:5.
Conclusions: Poor stability of amoxicillin in acidic environments can be overcome by using cyclodextrins and magnesium salts of glutamic and aspartic acids.

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Development of a Separation Method of Four Penicillin Derivatives by Capillary Electrophoresis

Simon Brigitta1, Hancu G2, Gyéresi Á2

1 Martin Luther str. 79, Săcele, Brașov
2 University of Medicine and Pharmacy of Tîrgu Mureş, Faculty of Pharmacy, Department of Pharmaceutical Chemistry

Introduction: The objective of this paper is the development and optimization of a capillary electrophoresis method, which allows the separation of four frequently used penicillin derivatives (amoxicillin, ampicillin, benzilpenicillin and oxacillin), with possible application in the analysis of environmental samples.
Material and method: In our experiments we worked on water solutions of the studied penicillins. The analysis was performed on an Agilent Capillary Electrophoresis System with a diode array detector. The data were recorded and processed by Chemstation software.
Results: Different buffer solutions were tried out in order to reach the most efficient separation of the studied compounds. The influence of different analytical parameters was evaluated by varying the buffer concentration, buffer pH, voltage, temperature, injection time and pressure. The analytical performance of the method was verified, in order to estimate reproducibility and sensitivity.
Conclusions: A micellar electrokinetic capillary chromatography method has been developed for the separation of the four penicillins. We obtained the best results with a buffer solution containing 25 mM sodium tetraborate and 100 mM sodium dodecyl sulfate (pH = 9.3), the separation being achieved in approximately 5 minutes.

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