Itraconazole loaded nano-structured lipid carrier for topical ocular delivery: Optimization and evaluation

Low penetration efficiency and retention time are the main therapeutic concerns that make it difficult for most of the drugs to be delivered to the intraocular tissues. These challenging issues are often related to those drugs, which have low or poor solubility and low permeability. The goal of this study was designed to develop nanostructured lipid carriers (NLCs) loaded with itraconazole (ITZ) with the objective of enhancing topical ocular permeation and thereby improving clinical efficacy.

ITZ-loaded NLCs were fabricated by a high-speed homogenization technique using surfactant (Poloxamer 407), and lipids (stearic acid and oleic acid). Optimization of formulations was performed by 3 level factorial design and the selected formulation (F6) was evaluated by differential scanning calorimetry and transmission electron microscopy. Antifungal activity was assessed by measuring the zone of inhibition and irritation potential using the HET-CAM test.

The independent variables (lipid ratio-X₁ and percentage of emulsifier-X₂) have a positive impact on percentage entrapment efficiency (Y₂) and percentage release (Y₃) but have a negative impact on particle size (Y₁). Based on the better entrapment efficiency (94.65%), optimum particle size (150.67 nm), and percentage cumulative drug release (68.67%), batch F6 was selected for further evaluation. Electron microscopic images revealed that the prepared particles are spherical and have nano size. Antifungal studies demonstrated enhancement in the zone of inhibition by formulation F6 as compared to a commercial eye drop. The non-irritancy of optimized formulation (F6) was confirmed with a zero score.

In summary, the optimized NLCs seem to be a potent carrier for the effective delivery of itraconazole in ocular therapy.