In this work, the production of inhalable polymeric microparticles with modulable porosity is described. The starting polymeric material was the PHEA-g-RhB-g-PLA graft copolymer, which was suitably processed by spray drying (SD). Thanks to the addition of AB (weight percentage equal to 10 and 20 % with respect to the polymer) in the liquid feed, three biocompatible matrices were obtained with an increasing porosity in terms of pore volume (from 0.015 to 0.024 cc/g) and pore average diameter (from 1.942 to 3.060 nm), a decreasing tapped density values (from 0.75 to 0.50), and favorable aerosolization characteristics. These differences were highlighted also by a significant increase in the release of Rapamycin from the sample which showed the higher porosity (31.0 wt% after 24 hrs incubation) than the sample with the lowest porosity (14.9 wt%) in simulated lung fluid.
Keywords: Porous microparticles; Pulmonary administration; Rapamycin; l-aspartamide (PHEA); α,β-Poly(N-2-hydroxyethyl)-D.
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