Preparation and characteristics of erythromycin microspheres for lung targeting

If erythromycin is micronized into microspheres with suitable particle size, it can improve pulmonary drug concentration to maximize its effectiveness and minimize the adverse side effects.

In this study, erythromycin gelatin microspheres (EM-GMS) were prepared and some characteristics of EM-GMS were investigated. The drug-targeting index (DTI) of EM-GMS was evaluated to predict their potential as a targeted delivery system.

Erythromycin was microencapsulated with gelatin by a double emulsion solvent evaporation method. Some characteristics of EM-GMS, including morphology, particle size, in vitro release, and safety were researched.

EM-GMS had a spherical shape and smooth surface morphology. The drug loading and encapsulation efficiency of EM-GMS were 13.56 +/- 0.25% and 55.82 +/- 2.23%, respectively. The release of erythromycin from EM-GMS showed an initial burst and following a sustained release, with an accumulate release of 80% at 4 hours. The EM-GMS was safe since there was no vein irritation and no hemolysis on the erythrocyte of rabbit at 3.5 mg/mL and a LD50 of 173.07 mg/kg. After administering EM-GMS to rabbits, the concentration of erythromycin in lung was 15.92 times higher than that in plasma and the DTI of EM-GMS in lung was 6.65 as compared with erythromycin lactobionate.

The preparation technology of EM-GMS for lung targeting was successful and the quality of microspheres was good.