(118a) Biodegradable Polymer Capsule for Long-Term Drug Release

Voice disorders, which are common communication disorders in the US, can result from various conditions affecting the larynx, respiratory system, or vocal tract. Vocal fold scarring, often caused by injury and inflammation, is a common cause of dysphonia, and current therapeutic options are limited. Airway stenosis, a narrowing of the airway, poses a serious problem for both adults and children and can result from various causes. Surgical procedures are often required to address severe cases of airway stenosis, but they can lead to inflammation and other complications.

Corticosteroids, known for their anti-inflammatory properties, have been used in the treatment of laryngeal diseases. Local administration of corticosteroids directly into the larynx has shown promising results, especially in reducing scarring and inflammation. However, the effectiveness of current corticosteroid delivery methods is limited by factors such as short duration of action, discomfort, and costs associated with repeated procedures.

To address these limitations, we have developed sustained-release capsule implants for local delivery of dexamethasone (Dex). Four different biodegradable polymers (polycaprolactone, poly(lactic acid), 90:10 poly(lactic-co-glycolide), and 50:50 poly(lactic-co-glycolide)) were used as capsule materials. The release profiles of Dex from these capsules were compared, and the 50:50 poly(lactic-co-glycolide) showed the fastest release. The permeability and partition coefficient of each polymer were measured, and it was found that the release of Dex through the capsule membrane was primarily due to “solution-diffusion” rather than diffusion through pores. The hydrophobicity of the polymer sheet was found to correlate with the drug release kinetics, with more hydrophobic polymers exhibiting slower release rates for the hydrophilic drug Dex. In vitro studies demonstrated the effective suppression of pro-inflammatory cytokine IL-6 levels using the Dex-loaded implant, indicating its potential therapeutic benefits with minimal toxicity.

Overall, the development of the biodegradable polymer capsule for long-term release of Dex holds promise for improving the treatment of voice disorders, airway stenosis, and other related conditions.