Preparation and characterization of a lutein loading nanoemulsion system for ophthalmic eye drops

Nanoemulsions (NE) are advantageous nanosized delivery agents for ophthalmic medications because of their ability to penetrate into the ocular structure, as well as their sustained effects. We prepared a NE system composed of isopropyl myristate, triacetin, Tween 80, and ethyl alcohol to increase the solubility and permeability of lutein, an effective medication in macular degeneration. The pseudo-ternary phase diagram was constructed to identify the self-emulsifying region. Eight formulations were selected to characterize each formulation. We examined physical characteristics including particle size, drug solubility, formulation stability, and turbidity. We selected the optimized formulations NE 5 (NE-5) and NE-8, both of which are transparent. The particle size of NE was ca. 10-12 nm with a narrow size distribution. Neither separation nor change in the particle size was observed for 7 days. The lutein loading NEs demonstrated a significant increase in lutein release and sustained release. In contrast, lutein prepared with oil and starch had limited drug release profiles under 5%. The prepared lutein NE formulation is a potential alternative for lutein delivery systems.