Dynamic SIMS utilizing SF5þ polyatomic primary ion beams for drug delivery applications

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 SF5þ 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 SF5þ primary ion dose, and it was found that the molecular ion signals of both polymer and drug remained constant for ion doses up to 5 1015 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 main chain 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. # 2004 Elsevier B.V. All rights reserved.