Effect of cellulose derivatives on alginate micro spheresprepared by emulsification

Abstract

Generally discrete and spherical calcium alginate micro spheres with a high drug encapsulation efficiency were readily prepared by an emulsification process. They were found to release drug rapidly., In the present study copolymer in the form of cellulose derivatives was added to sodium alginate in an attempt to modify the drug release profiles of the micro spheres., The effects of cellulose derivatives on the morphology and drug encapsulation efficiency of the micro spheres were also evaluated., The cellulose derivatives increased the degree of agglomeration of the micro spheres., Small and spherical micro spheres were produced from cellulose derivatives of low viscosity while larger micro spheres which tended to be elongated were produced from cellulose derivatives of high viscosity., The drug encapsulation efficiency and the drug release profiles were influenced by the chemical nature of the cellulose derivative as well as its viscosity., The efficiency of drug encapsulation generally increased while the rate of drug release decreased with increasing viscosity of the cellulose derivatives., Less hydrophilic cellulose derivatives such as methyl cellulose and hydroxypropylmethyl cellulose were found to increase the efficiency of encapsulating sulphaguanidinewhile more hydrophilic cellulose derivatives such as hydroxypropyl cellulose and carboxymethyl cellulose had the opposite effect., Among the cellulose derivatives usedonly hydroxypropyl cellulose retarded the drug release of the micro spheres.

Key Words:

• Microsphere
• alginate
• cellulose derivatives
• emulsion