Abstract
Three-dimensional (3-D) molecular imaging in polymeric biomaterials, particularly in the near surface region (1 nm to 500 nm), is extremely important for drug delivery applications, as these regions play a vital role in both the biocompatability and drug release characteristics in drug delivery systems. Although pharmaceutical companies typically use dissolution studies to monitor the rate of drug release, these studies need to be correlated with actual structural information, compositions and defects within the device. This work discusses the most recent advances and challenges in utilizing Cluster Secondary Ion Mass Spectrometry (cluster SIMS) for 3-D characterization and quantification in polymer-based drug delivery systems. The results are promising, showing the ability to quantify and image the 3-dimensional distribution of drugs in polymer layers. However, many problems still remain in terms of analysis of real-world samples, including complex sample geometries, ionization effects, and beam-induced sample damage. These problems, and how to address them, are discussed briefly here.
