Preparation And In-vitro Release Of Biodegradable Erythromycin-loaded Microspheres

Erythromycin, one of the most successful drugs of all time, is a mixture of macrolides produced by the fermentation of the fungus, streptomyces erythreus. The antibacterial activity of erythromycin stems from its ability to inhibit protein biosynthesis3. Although allergic reactions to erythromycin are unusual, the use of erythromycin suffers from a few limitations such as hepatotoxicity and degradability in acid. Erythromycin degrades in acidic conditions found in the stomach and produces inactive byproducts4, which are responsible for its poor bioavailability and gastrointestinal side effects. In order to prevent its degradation in the presence of acid, a new drug delivery systems should be investigated to provide a wider tolerance for oral administration.Drug delivery technology presents an interesting interdisciplinary challenge for the pharmaceutical5, chemical, engineering, biomaterials and medical communities. Owing to their physiochemical and biological properties, gelatin has recently been considered as a potential material for drug delivery systems.Gelatin microspheres were prepared by using emulsion chemical-crossline technique. In order to gain the best homogeneous size and parameters, it was demonstrated that solidifying reagent adding time had effects on gelatin microspheres for the first time. The conditions of the microspheres preparation such as gelatin concentration, agitate rate, ratio of water to oil phase were discussed. The surface morphology and the size of the microspheres were observed by SEM. The result shows that the microspheres we prepared have relatively uniform diameter ,the average diameter in this study is 13.72μm,and the surface of the microspheres is smooth. In order to improve the fabricating technics, gelatin was refined and was divided into three parts by the molecular weight. The result showed that the size of the microspheres with refined gelatin was more homogeneous than without.Preparing erythromycin-gelatin microspheres, via a W/O emulsion process, can protect therapeutic agent from acid and enzymatic degradation and controlled release a therapeutic agent in tissue to improve bioavailability. The erythromycin-gelatin microspheres were developed for the controlled release of erythromycin and were investigated the effect of enzymatic degradation and biocompatibily. The objective of this study was to examine the factors influencing the size of microspheres .The entrapment efficiency and the initial burst release was examined in different release system.Erythromycin release from the microspheres was monitored in buffer and artificial body fluid at 37℃. Average drug content was 27.2% and erythromycin-loaded gelatin microspheres showed good release profiles with a nearly constant release during 4~8 hours in artificial body fluid in vitro degradation studies. These gelatin microspheres would be useful for studying and developing various drug delivery systems.