Treatment of restenosis by controlled-release delivery systems of tyrphostins

Percutaneous transluminal coronary angioplasty (PTCA) procedures include balloon dilation, excisional atherectomy, endoluminal stenting, and laser ablation. However, despite significant advances in reducing the acute complications of percutaneous revascularization procedures with premedications and better techniques, chronic restenosis of dilated lesions remains a serious and frequent problem. The neointimal formation is dependent on smooth muscle cells and most probably fibroblast proliferation and migration mediated by various cytokines and growth factors. The unsuccessful attempts to control restenosis by systemic pharmacological interventions have prompted many researchers to look for more promising therapeutic approaches such as local drug delivery. In this review we discuss the rationale for local drug delivery based on restenosis pathophysiology, local drug delivery approaches, the rationale for antiproliferative therapy, and review the in vitro and in vivo studies of local drug delivery systems of tyrphostins (protein tyrosine kinase inhibitors) in restenosis therapy.