The behavior of various biodegradable polymer films (e.g. polylactic acid, polyglycolic acid and polycaprolactone) as well as some model drugs (theophylline and 4-acetamidophenol) under dynamic SF5+ primary ion bombardment is explored. A series of polylactic acid films containing varying concentrations of 4-acetamidophenol are also analyzed under similar conditions. The resultant molecular depth profiles obtained from these polymer films doped with drug show very little degradation in molecular signal as a function of SF5+ primary ion dose, and it was found that the molecular ion signals of both polymer and drug remained constant for ion doses up to ~5x1015 ions/cm2. In addition, the polymer film / Si interface was well defined which may imply that sputter-induced topography formation was not a significant limitation. These results suggest that the structure of the biodegradable polymers studied here which all have the common structural unit, R-CO-O-R, allows for a greater ability to depth profile due to ease of bond cleavage. Most importantly however, these results indicate that in these particular polymer systems, the distribution of the drug as a function of depth can be monitored.
Citation: Applied Surface Science
Pub Type: Journals
cluster, depth profile, drug delivery, SF<sub>5</sub><sup>+</sup>, TOF-SIMS