AVS 53rd International Symposium
    Applied Surface Science Wednesday Sessions
       Session AS-WeM

Paper AS-WeM11
Multi-Technique Characterization of a Drug Delivery System to Obtain 3-D Chemical Information

Wednesday, November 15, 2006, 11:20 am, Room 2005

Session: Molecular Ion Sources and Characterization of Biomaterials
Presenter: A.M. Belu, Medtronic, Inc.
Authors: A.M. Belu, Medtronic, Inc.
C.M. Mahoney, National Institute of Standards and Technology
K. Wormuth, SurModics, Inc.
Correspondent: Click to Email
Medical devices are increasingly being designed to incorporate drug delivery. For example, drugs are currently incorporated into catheters to reduce microbial infection, placed on stents to prevent restinosis of the artery, and incorporated into pacing lead tips to prevent inflammation of heart tissue. As more drug delivery systems are being created, it is important to characterize their properties, and relate the properties to how the system will function in the human body. This study focuses on the characterization of a rapamycin/PLGA delivery system on a stent. The goal is to understand the lateral and depth distribution of the drug in the polymer film. The information can then be used to predict the release profile of the drug in vivo. Several different formulations of rapamycin/PLGA were studied (5, 25, 50% drug, and 25% with a capcoat). The surface composition of the films were characterized and quantified by ESCA and TOF-SIMS. Information on drug concentration from the surface towards the bulk of the film was determined by depth profiling by SIMS with a cluster ion source. To determine the distribution of drug/polymer species in the bulk of the film in the x-, y-, and z-direction, confocal Raman was used. In the films with high concentration of drug, individual clusters of drug on the order of a few microns were resolved. The data from the multiple methods of characterization will be compiled to allow a fuller understanding of the delivery systems. The strengths and weaknesses of each of the characterization techniques will be compared.