Ocular inserts for controlled release of antibiotics

Ocular inserts impregnated with antibiotics (erythromycin and erythromycin estolate) which have sustained release characteristics were prepared, mainly for the purpose of trachoma therapy. In vitro experiments showed that the elution rate of a drug with low solubility in water (erythromycin estolate) is constant when the water content of the hydrogel insert is more than 30%. In the case of a drug with higher solubility (erythromycin), the elution rate depends on the water content. Some in vivo experiments using rabbit eyes were also reported.