Tailored beads made of dissolved cellulose--investigation of their drug release properties

In the frame of this work, we have investigated drug entrapping and release abilities of new type of porous cellulose beads (CBs) as a spherical matrix system for drug delivery. For that purpose, CBs prepared with three different methods were used as drug carriers and three compounds, anhydrous theophylline (Thp), riboflavin 5'-phosphate sodium (RSP) and lidocaine hydrochloride monohydrate (LiHCl) were used as model drug substances. The loading procedure was carried out by immersing swollen empty beads into the solutions of different concentrations of model drugs. The morphology of empty and loaded beads was examined using a field emission scanning electron microscopy (FE-SEM). Near-infrared (NIR) imaging was performed to identify the drug distributions on and within the loaded CBs. The drug amount incorporated into CBs was examined spectrophotometrically and in vitro drug release studies were performed to determine the drug release rates. The results of FE-SEM and chemical NIR imaging analyses revealed that incorporated drug were distributed on the surface and but also within the internal structure of the CBs. Physical properties of CBs and solubility of model drugs had effect on loading efficacy. Also, the drug release rates were controlled by solubility of model drugs (diffusion controlled release). In conclusion, CBs from dissolved cellulose show promise in achieving controlled drug delivery.