Mechanism of drug release from beads containing diclofenac sodium dispersed in compritol 888 and encapsulated in Alginate

Sustained release polymer beads containing- diclofenac sodium [DNa] dispersed in compritol 888 and encapsulated in calcium alginate shell were prepared by utilizing 2[3] factorial design. When the release data were fitted to the first-order equation, Higuchi square root equation or Hixson-Crowel cube root equation, first-order equation shows best fitting. The release data [570%] were also analyzed by the equation suggested by Ritger and Peppas. The exponent n was found to be higher than that expected from diffusion-controlled systems. Both diffusion and erosion contribute to the release of DNa from the beads