SIMS depth profiling of polymer blends with protein based drugs

Use of TOF-SIMS to study adsorption and loading behavior of methylene blue and papain in a nano-porous silicon layer

“…Molecular and elemental information is obtained for organic and inorganic materials providing a powerful technique to image organic compounds associated with inorganic substrates or vice versa [9,10]. This has been demonstrated by imaging solid-state pharmaceutical formulations [11][12][13][14], however, to date this has not been extended to porous silicon substrates.In this study, TOF-SIMS was used to map the distribution of methylene blue and papain across porous silicon layers after loading from aqueous solution. Methylene blue (C 16 H 18 N 3 S ϩ , MW ϭ 284.12 g/mol) is a relatively small organic dye molecule commonly used in adsorption studies and can be considered analogous to therapeutic molecules.…”

“…Molecular and elemental information is obtained for organic and inorganic materials providing a powerful technique to image organic compounds associated with inorganic substrates or vice versa [9,10]. This has been demonstrated by imaging solid-state pharmaceutical formulations [11][12][13][14], however, to date this has not been extended to porous silicon substrates.…”

Molecular Depth Profiling with Cluster Ion Beams

“…32,35 Figure 5.6 illustrates the process used by Mahoney et al to obtain quantitative depth profiles from a series of poly(lactic acid) (PLA)/Pluronic ® P104 blends (∼1 μm thick, cast on Si) which have potential as protein drug delivery vehicles. 32,36 Pluronic P104 is a triblock copolymer, consisting of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) components. The amphiphilic nature of the P104 polymer in combination with its increased biocompatibility means that it is well suited to protect protein components via micelle encapsulation, and thus increase their stability in hydrophobic polymer matrices, such as PLA.…”

“…36 Depth profile attempt of Irganox delta layer standard, acquired using 8 keV SF 5 + for sputtering, combined with 25 keV Bi 3 + for analysis. The sample temperature was maintained at −100 • C during the experiment.…”

Poly(Lactic Acid) Blends

“…The Pluronic/PLA blends were compatible and had a lower T g than neat PLA, demonstrating the plasticizing effect of Pluronic. Lee et al [222] and Mahoney et al [223] found greater segregation of the blend on the surface than in the bulk for spun-cast material. The PPO segments appeared predominantly on the surfaces of the material, while the PEO segments were predominantly within the bulk phase [222][223][224].…”