Ultrahigh Drug Loading and Release from Biodegradable Porous Silicon Aerocrystals

Biodegradable porous silicon (pSi) is under assessment for the controlled release of both proteins and poorly-soluble API formulations. Super-critical drying of ultrahigh porosity (90%) porous silicon is shown here to preserve much higher mesopore volumes (up to 4mL/g) and surface areas (up to 600m2/g) than achievable with standard air drying. The payloads and physical state of the model drug (S) (+) ibuprofen, as loaded within a super-critically dried porous silicon carrier matrix, were quantified and assessed using TGA, DSC, cross-sectional EDX, XRD, Raman mapping and FT-IR. In-vitro biodegradability was assessed using molybdenum blue assay and drug release using RP-HPLC. Entrapped drug payloads as high as 70%w/w have been achieved, substantially higher than values reported for other mesoporous materials. The entrapped (S) (+) ibuprofen showed faster release than bulk (S) (+) ibuprofen.