title: Balloon coating with rapamycin using an on-site coating device.
abstract: OBJECTIVE
  The efficacy of drug-eluting balloons has been demonstrated in clinical trials. The drug predominantly used is paclitaxel because of its lipophilic properties and the rapid onset of action. The aim of the investigation was to evaluate the feasibility and efficacy of an alternative balloon coating with rapamycin that can be applied on site.
  
  
  METHODS
  The balloon coating (3.0/18 and 3.0/12 mm, Cathy No. 4, Translumina GmbH) with rapamycin was conducted with a coating machine (Translumina GmbH). Concentrations were 2, 2 × 2, 3, and 4 %. Measurements regarding the amount of substance released to the vessel wall were carried out on explanted porcine coronaries by means of ultraviolet and visible-light spectroscopy. Inflation time varied between 30 and 120 s. The biological effect of the coating was evaluated in a porcine peripheral overstretch and stent implantation model.
  
  
  RESULTS
  The amount of rapamycin on the balloon surface ranged from 558 ± 108 μg for the 2 % solution to 1,441 ± 228 μg in the 4 % solution. An amount of 95 ± 63-193 ± 113 μg was released into the vessel wall. The quantitative measurements of the angiographic examinations 4 weeks after treatment revealed a reduction of diameter stenosis from 20.6 ± 17.4 % in the control group to 11.6 ± 5.5 % in the drug-eluting balloon group.
  
  
  CONCLUSIONS
  A balloon coating with rapamycin omitting an excipient is possible with a dose-adjustable coating machine. However, the biological effects are moderate, which make further optimization of the coating process and evaluation of appropriate excipients necessary.
authors: Department of Diagnostic and Interventional Radiology, University Hospital of Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany. joerg.schmehl@med.uni-tuebingen.de
authors: Jörg
authors: J
authors: Schmehl
authors: Jürgen
authors: J
authors: von der Ruhr
authors: Markus
authors: M
authors: Dobratz
authors: Rainer
authors: R
authors: Kehlbach
authors: Isabelle
authors: I
authors: Braun
authors: Tim-Oliver
authors: TO
authors: Greiner
authors: Claus D
authors: CD
authors: Claussen
authors: Boris
authors: B
authors: Behnisch
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D000818:Animals; D017023:Coronary Angiography; D016503:Drug Delivery Systems; D005240:Feasibility Studies; D007150:Immunohistochemistry; D008855:Microscopy, Electron, Scanning; D020123:Sirolimus / Q000494:pharmacology*; D013499:Surface Properties; D013552:Swine
chemical_list: D020123:Sirolimus