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 600m2M/g) than achievable with standardair 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 andFT-IR. In-vitro biodegradability was assessed using Mmolybdenum blue assay and drug release using RPHPLC. 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

Porous Silicon Fabrication by Anodisation: Progress towards the Realisation of Layers and Powders with High Surface Area and Micropore Content

International audienceWith a view to producing thick and very high surface area microporous silicon layers (and subsequently powders) by electrochemical anodisation, the incorporation of various types of chemical additives has been investigated, these in combination with hydrofluoric acid electrolyte and high-resistivity p-type parent substrates. Comparison under constant charge conditions shows that anodisation using 50 wt% hydrofluoric acid, or inclusion of the additives hydrochloric acid, sulphuric acid, or ammonium dodecylsulfate with lower concentration hydrofluoric acid, can facilitate powders with internal surface areas of up to 864 m2/g, average pore sizes in the region of 2.8–3.2 nm, and pore volumes in excess of 0.8 cm3/g – all as determined using nitrogen gas adsorption and associated isotherm analysis. Porous silicon powders with appreciable micropore content have thus been achieved, for the first time. Relevant application areas for such material are diverse, and potentially include energetics, impurity gettering, gas sensing microchips, orthopaedic implants, hydrogen storage, and Li-ion battery anodes