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.
Improvements of Amoxicillin Stability in Acidic Environment
Full text: PDF
