In Vivo Release of Zafirlukast from Electrospun Polyisobutylene-Based Fiber Mats to Reduce Capsular Contracture of Silicone Breast Prostheses.

Silicone rubber tissue expanders and breast implants are associated with chronic inflammation, leading to the formation of fibrous capsules. If the inflammation is left untreated, the fibrous capsules can become hard and brittle and lead to formation of capsular contracture. When capsular contracture occurs, implant failure and reoperation is unavoidable. Fibrous capsule formation to medical grade silicone rubber breast implants and polyisobutylene-based electrospun fiber mats attached to silicone rubber with and without an anti-inflammatory therapeutic were compared. A linear polyisobutylene (PIB)-based thermoplastic elastomer is currently applied as a polymer coating for drug release on coronary stents to reduce restenosis. Recent work has created a drug releasing electrospun fiber mat from PIB-based materials. Important to this study, poly(alloocimene-b-isobutylene-b-alloocimene) (AIBA) was electrospun with zafirlukast (ZAF). ZAF is an anti-inflammatory drug that is able to reduce capsule formation and complications to silicone breast implants. Fiber mats are advantageous for local drug delivery because of their high porosity and surface area for drug release. The chief hypothesis was that local release of ZAF from AIBA would lower inflammatory signaling and resulting capsular formation after 90 days in vivo. Electrospun AIBA mats locally released ZAF, lowering inflammation and fibrous capsule development compared to medical grade silicone rubber. Locally and orally released ZAF led to similar results, but the former had much lower concentration that highlights local delivery's therapeutic potential. Released ZAF from AIBA fiber mats mitigated inflammation and serves as an alternative to existing clinical approaches.