Purification of amoxicillin trihydrate in the presence of degradation products by different washing methods

Abstract

Repeated crystallization or the use of different chemicals to obtain a pure crystal can cause yield/purity issues. Therefore, impurities penetrating the crystalline mesh should be removed as much as possible without affecting the main product. In this study, the relationship between different washing methods and the purity/yield was examined for the first time and the lack of information about this process step was eliminated. For this purpose, amoxicillin trihydrate (Amct), which is one of the most consumed antibiotics in the world, and 4-hydroxyphenylglycine (4HPG) as an impurity were used in the study. The removal of impurities from the Amct crystal lattice using washing methods was demonstrated. Also, for the first time in this study, a full factorial design was carefully utilized to examine the relationship between the yield/purity and the washing methods, solutions and temperatures. In addition, a Büchner glass funnel was redesigned to operate at the desired temperature and without product loss, and a full range of trials was done here. This study contributes to the literature with different washing methods, a new experimental method and a redesigned Büchner glass funnel. From the main effect plot, it was determined that the factors affecting the yield/purity values were the washing method, temperature and solution, respectively. The highest yield was obtained with the one-stage washing method, while the highest purity was determined with the soaking method.