Nanostructured lipid carriers for triamcinolone acetonide delivery to the posterior segment of the eye

Triamcinolone acetonide (TA) is a corticosteroid drug currently administered by intravitreal injection for a broad spectrum of inflammatory, edematous and angiogenic ocular diseases. To increase the drug's bioavailability by ocular instillation, TA was encapsulated in nanostructured lipid carriers (NLC), previously optimized by our group using a factorial design approach. In the present paper, nanometric (∼200 nm), unimodal and negatively charged NLC loaded with the fluorescent lipid marker Nile red (NR-NLC) and drug (TA-NLC) were produced by high pressure homogenization. Based on the selected formulations, in vivo tests were carried out by eye-drop instillation of NR-NLC in mice, revealing the systems’ ability of delivering lipophilic actives to the posterior segment of the eye via the corneal and non-corneal pathways. Short and long-term stability of TA-NLC was assessed by high performance stability analysis using the Turbiscan®. The results showed a backscattering of less than 1.5% and during a period of 6 months, anticipated the low tendency of these particles for aggregation during shelf life when stored at room temperature.

Changes in the accumulated fluorescence intensity in the Inner Plexiform Layer after eye-drop administration of Nile red loaded nanostructured lipid carrier (NR-NLC) and Nile red solution (NR-solution), and the fluorescence microscopic images of the retina 40 min after treatment with (a) Nile red loaded nanostructured lipid carrier, and (b) Nile red solution.Figure optionsDownload as PowerPoint slideHighlights
• Precirol®ATO5 and Squalene® NLC were produced with 0.025% triamcinolone acetonide.
• In vivo tests were carried out by eye-drop instillation of Nile red-NLC in mice.
• TA-NLC showed a backscattering of less than 1.5%, anticipating low tendency for aggregation.