Effect of Process Variables on Drug Release from Microparticles Containing A Drug-Resin Complex

Abstract

Microparticles consisting of dextromethorphan-resin complex (resinate) coated with a cellulose derivative were prepared by a modified emulsion-solvent evaporation method. Adjustment of the release rate was achieved by varying resinate (core) to polymer (coat) ratio or by using additives. Higher ratios of resinate to polymer gave faster release of the drug. Polyethylene glycol (PEG) 4000 also increased the release rate. Increasing core to coat ratio also increased average particle size. Placing the emulsifying agent in different phases of the emulsion in the fabrication process also affected the particle size distribution. The microparticles showed good sustained release of the drug