Release of donepezil hydrochloride from sodium alginate, sodium alginate/sodium carboxymethyl cellulose and sodium alginate/sodium carboxymethyl cellulose/poly(vinyl alcohol)-graft-acrylamide microspheres

In this study; an alzheimer drug donepezil hydrochloride (DP) was encapsulated in to sodium alginate (NaAlg), sodium alginate/sodium carboxymethyl cellulose (NaAlg/NaCMC) and sodium alginate/sodium carboxymethyl cellulose/ poly(vinyl alcohol)-graft-acrylamide (NaAlg/NaCMC/PVA-graft-AAm microspheres by emulsion crosslinking method. Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used to characterize the grafted copolymers and the microspheres. SEM confirmed the spherical nature of the particles. Microspheres were also evaluated for their particle sizes, equilibrium swelling values, entrapment efficiencies, molecular mass between cross-links, diffusion coefficient (Mc) and release profiles. The effects of NaAlg/NaCMC, and NaAlg/NaCMC/PVA-graft-AAm ratio, crosslinking agent concentration and time, drug/polymer ratio (d/p), pH and type of crosslinker on the entrapment efficiency and the release of DP were examined.The best condition for the release of DP was found to be 92.9 % for the microspheres prepared by NaAlg/NaCMC/PVA-graft-AAm ratio of 2/1/1 (w/w/w), d/p ratio of 1/8 (w/w) crosslinked with FeCl3 (7 %) (w/v) for 30 minutes. The release kinetics were described with fickian and non fickian approaches.