Biodegradable Hyaluronic Acid Insert Shows Promise For Treating Dry Eye

A biodegradable hyaluronic acid insert may lower inflammatory biomarkers and enable water retention in individuals with dry eye disease, according to research published in Drug Delivery Science and Technology. The insert is able to deliver the drug in a controlled release manner for an extended time period, according to the report. 

Nanofibers of the drug (0.1%, 0.2% and 0.5%) were prepared with polyvinyl alcohol using an electrospinning technique. The formulation had a uniform thickness between 0.33 and 0.35 nm and a pH of 7.4 to prevent ocular surface irritation. The team performed in vitro studies to assess drug release, in vivo studies involving mice to examine tear film secretion changes, and a histopathological analysis to determine inflammatory cytokine levels. 

In vitro assessments of the biodegradable hyaluronic acid insert revealed a controlled release pattern. During a 12-hour period, the 0.5%, 0.2%, and 0.1% formulations released 78.06%, 90.96%, and 91.81% of the drug, respectively. 

The murine model in vivo assessment involved using benzalkonium chloride to induce dry eye symptoms in mice during a 7-day period. Following this period, the investigators performed Schirmer testing and measured percentage change in the length of the wetted strips to determine tear volume secretion. Overall, the length of the strips increased from 1.57% to 2.77% and from 1.50% to 2.83% among mice in formulation and market formulation groups, respectively. 

Tear cytokine analysis revealed lower inflammatory markers among mice treated with the  biodegradable hyaluronic acid insert. TNF-alpha concentration was 306.32% in mice with induced dry eye that were not treated with the insert compared with 132.30% and 126.62% in the formulation and marketed formulated groups, respectively. 

“Ocular [inserts] are thin, sterile, solid or semisolid devices [consisting] of a polymeric thin film that is placed in the cul de sac which releases the drug at a steady and consistent rate, reduces systemic absorption, enhances contact and retention time,” according to the study authors. “With no preservatives, ocular insert[s] [lower] the likelihood of any sensitive reaction as compared to other existing traditional therapies.”