Content Determination, Efficacy Evaluation Of Ultrafine Azithromycin And Micronization Study Of Dirithromycin

Azithromycin (AZM), as a new macrolide antibiotic, has been paid increasing attention in clinical application. Due to its poorly water-soluble property, the clinical bioavailability of oral administration forms which is the main formulation of AZM is very low. We carried out micronization study in the prophase, successfully prepared ultrafine AZM with smaller particle size, bigger BET surface and improved dissolution rate compared with the crude material.In this study, ultrafine AZM particles were successfully prepared in RPB. We developed HPLC method for the purpose of AZM content determination. Subsequently, the content of the ultrafine AZM was precisely detected using this simple but accurate method. The pharmacological activity of ultrafine products was evaluated by the in vitro and in vivo antibacterial test. What’s more, in order to obtain the AZM-like spherical particle, the micronization of dirithromycin by anti-solvent recryctallization was studied.The experimental results indicated that the micronization process of AZM was sensitive with a high yield about99.42%, the products prepared under same condition had certain differences in particle morphology and BET surface area. The study of AZM content determination using the as developed, simple, accurate HPLC method showed that the content of the ultrafine AZM was pretty close to that of the crude drug. After the in vitro and in vivo antibacterial characterization, we found that the pharmacological activity of ultrafine products was better than the crude material, which to some extent related to the morphology of the particles. The micronization study of dirithromycin suggested that by means of anti-solvent recrystallization we can’t get the azithromycin-like but small spherical particle with a size about2μm, the dry powder of the particle was very hard to obtain.