Site‐specific delivery of dexamethasone from biodegradable implants reduces formation of pericardial adhesions in rabbits

Abstract

Repeated sternotomy often leads to serious complications in patients due to the formation of cardiac adhesions. In this study we characterized dexamethasone-loaded biodegradable poly(lactide)-poly(ethyleneglycol) copolymer films for site-specific drug delivery and examined their efficacy in the rabbit model of postoperative cardiac adhesions. Tritiated dexamethasone-loaded films were used to determine the in vitro release and in vivo drug distribution. Dexamethasone release in serum was biphasic with 69% drug released after 72 hr. The implants produced sustained drug levels at the implantation site with low distribution into the peripheral tissues. The matrices were implanted in rabbits between the epicardium and the sternum following sternotomy, pericardiectomy and epicardium abrasion, with the drug-releasing surface facing the epicardium. The tenacity and density of the adhesions was examined 21 days post procedure in comparison to both groups of untreated and rabbits implanted with blank matrices. Similarly tenacious and dense adhesions were observed in both control groups. In contrast, epicardial adhesions' formation was significantly reduced and the anatomy was preserved in the treated animals. It is concluded that local delivery of dexamethasone from biodegradable implants provides a promising approach for the prevention of pericardial adhesions while potentially minimizing the systemic adverse effects inherent to systemic therapy or high blood levels of the drug.

Encapsulation of cell‐adhesive RGD peptides into a polymeric physical hydrogel to prevent postoperative tissue adhesion

“…In general, there are two anti‐adhesion strategies: (1) pharmaceutical treatments5, 6 and (2) barrier‐based devices 7–10. To prevent tissue adhesion, a number of bioactive substances such as anti‐inflammatory agents11, 12 and fibrinolytic agents5, 13 have been tried. Pharmaceutical treatments alone do not prevent adhesions very effectively due to the rapid loss of drugs from the peritoneum, and thus sustained release is required.…”

Reduction in postsurgical adhesion formation after cardiac surgery by application of N,O-carboxymethyl chitosan

“…A common feature in a number of these interventions has been an attempt to establish a physical barrier between injured surfaces by the application of films or gels. [2][3][4] Problems have arisen limiting the ease of use of many of these products in the clinical setting. For example, polytetrafluoroethylene membranes have been demonstrated to effectively reduce cardiac adhesion formation in clinical trials.…”

Reduction in postsurgical adhesion formation after cardiac surgery in a rabbit model using N,O-carboxymethyl chitosan to block cell adherence

“…A common feature in a number of these interventions has been an attempt to establish a physical barrier between injured surfaces by the application of films or gels. [2][3][4] A chitosan derivative, N,O-carboxymethyl chitosan (NOCC), has shown significant promise as an antiadhesion agent. A number of reports have provided evidence that this agent limits adhesion formation and adhesion reformation in animal abdominal injury models.…”