Development of a conjunctival contact–type drug delivery device for latanoprost using hyaluronic acid

Effective topical drug delivery is crucial for glaucoma treatment, necessitating more convenient methods to enhance patient compliance. This study evaluates the efficacy and safety of using freeze-dried hyaluronic acid (HA) as a carrier for a novel conjunctival-contact drug delivery system. We developed HA tablets loaded with latanoprost (HA-latanoprost) and verified the concentration using high-performance liquid chromatography. Twenty mice (C57BL6) were divided into four groups (<i>n</i> = 5 per group): normal saline (group 1), control HA tablet (group 2), Xalatan™ (group 3), and HA-latanoprost tablet (group 4). Treatments were administered to the right eyes, with the left eyes serving as no-treatment controls. Intraocular pressure (IOP) and irritation (measured by scratching motions) were monitored for 10 days. On day 10, we quantified gene expression of inflammatory cytokines and IOP-affecting proteins using polymerase chain reaction, and performed histological and immunohistochemical analyses. Results showed that IOP was significantly lower in groups 3 and 4 compared to the other groups, with group 4 exhibiting the greatest reduction by day 10. Group 4 also experienced less irritation. Additionally, group 4 had lower expression of inflammatory cytokine genes and higher expression of IOP-lowering protein genes compared to group 3. No significant side effects were observed in any group. Overall, HA-latanoprost effectively lowered IOP and reduced ocular irritation more than latanoprost eyedrops in mice. However, these results are based on animal testing, so further development is needed for clinical use.