title: Depth profiling of 4-acetamindophenol-doped poly(lactic acid) films using cluster secondary ion mass spectrometry.
abstract: The feasibility of using cluster secondary ion mass spectrometry for depth profiling of drug delivery systems is explored. The behavior of various biodegradable polymer films under dynamic SF(5)(+) primary ion bombardment was investigated, including several films doped with model drugs. The SF(5)(+) depth profiles obtained from these biodegradable polymer films showed very little degradation in secondary ion signal as a function of increasing primary ion dose, and it was discovered that the characteristic ion signals for the polymers remained constant for ion doses up to approximately 5 x 10(15) ions/cm(2). These results suggest that the polyester structure of the biodegradable polymers studied here allows for a greater ability to depth profile due to ease of main chain scission. Attempts were also made to depth profile through a series of poly(lactic acid) (PLA) films containing varying concentrations of the drug 4-acetamidophenol. The depth profiles obtained from these films show very little decrease in both the 4-acetamidophenol molecular ion and PLA fragment ion signals as a function of increasing SF(5)(+) primary ion dose. Similar results were obtained with theophylline-doped PLA films. These results show that, in some drug delivery devices, it is possible to monitor the distribution of a drug as a function of depth by using cluster primary ion beams.
authors.affiliation: Chemical Science and Technology Laboratory, Surface and Microanalysis Science Division, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, Maryland 20899-8371, USA. christine.mahoney@nist.gov
authors.forename: Christine M
authors.initials: CM
authors.lastname: Mahoney
authors.forename: Sonya V
authors.initials: SV
authors.lastname: Roberson
authors.forename: Greg
authors.initials: G
authors.lastname: Gillen
mesh_terms: D000082:Acetaminophen / Q000032:analysis* / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry* / Q000378:metabolism; D011091:Polyesters; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*
chemical_list: D003692:Delayed-Action Preparations; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; D000082:Acetaminophen; C033616:poly(lactide)