Controlled steroid delivery via bioabsorbable stent: Safety and performance in a rabbit model

Background: Middle turbinate lateralization, adhesions, and inflammation are causes of suboptimal sinus potency following surgery. A bioabsorbable drug-cluting stent has been developed to maintain sinus patency while providing controlled steroid delivery to the sinus mucosa. The aim of this study was to characterize the in vivo drug delivery efficacy and tolerance of this stent in a rabbit model. Methods: Bioabsorbable stents coated with mometasone furoate Were placed bilaterally in the maxillary sinuses of 31 rabbits via dorsal maxillary sinusotomy. Animals were sacrificed between 5 days and 78 Weeks postoperatively. Efficacy was assessed by measuring tissue concentrations of steroid in maxillary sinus and nasal mucosa and by measurement of plasma steroid concentrations. Tolerance was assessed by histological evaluation of the sinus mucosa at different time points. Results: Therapeutic mucosal drug concentrations were attained in a time-dependent fashion (range 175-28,189 ng/g). Plasma drug concentrations were generally near or below the lower Unlit of quantification (15 pg/mL). Histopathological examination of the mucosa showed no differences in the reaction to steroid-coated stents versus nondrug-coated control stents, with inflammation, epithelial ulceration, and bony reaction ranging from none to mild at all time points. Microscopic fungal hyphae were noted in a small proportion of both treatment and control sinuses, without evidence of associated adverse tissue reaction. Conclusions: In a rabbit model, mometasone-coated bioabsorbable stents are able to provide local steroid delivery with negligible systemic absorption. Corticosteroid-eluting stents may prove useful following endoscopic sinus surgery in maintaining sinus potency and reducing inflammation. (Am J Rhinol Allergy 23, 591-596, 2009; doi:10.2500/ajra.2009.23.3391)