Cheap and easy-to-recycle solvent, aqueous NaOH with no additives, was used to dissolve cellulose and make crosslinker-free materials of various porosity, testing them as drug delivery devices. Cellulose solutions were gelled, coagulated in a non-solvent (water, ethanol) and dried either using supercritical CO$_2$ (aerogels) or low-vacuum evaporation (named "xerogels"). Aerogels were of density around 0.1 g/cm³ and specific surface area (SSA) 200-400 m²/g. A significant influence of the first non-solvent and of drying mode on material properties was recorded: when the first non-solvent was ethanol and low-vacuum drying performed from ethanol, aerogel-like xerogels were obtained with density around 0.2 g/cm³ and SSA of 200-260 m²/g. Other conditions resulted in cellulose with much lower porosity and SSA. All materials were evaluated as drug delivery devices in simulated gastro-intestinal fluids; theophylline was used as a model drug.

Materials of high porosity exhibited shrinking and rapid drug release whereas denser materials were swelling and showed slower release. Two release mechanisms were suggested: a diffusiondriven through aqueous media in the pores, and diffusion through swollen pore walls. The results demonstrate a large spectrum of options for tuning the properties of porous cellulose materials for drug release applications.