Controlled release of indomethacin from gluteraldehyde crosslinked sodium alginate and poly(vinyl alcohol)/sodium alginate microspheres

In this study, microspheres of sodium alginate (Na-Alg) and poly(vinylalcohol)/sodium alginate (PVA/Na-Alg) were prepared to encapsulateindomethacin which is a nonsteroidal, anti-inflammatory drug. Microsphereswere prepared by liquid curing method by crosslinking with gluteraldehyde,and characterized by Fourier transform infrared (FTIR) spectroscopy,differential scanning calorimetry (DSC) and scanning electron microscopy(SEM).SEM results confirmed the spherical nature of the particles. Microspheres werealso characterized by particle diameters, equilibrium swelling values andentrapment efficiencies and release profiles.Equilibrium swelling experiments indicated that the swelling of the spheresdecreased with the increase in crosslinking time however diameter of thespheres does not affected considerably.The release studies were carried out at three pH values namely 1,2 , 6,8 and 7,4respectively and it was observed that as the pH of the medium increasedpercentage of cumulative release increased.The release of indomethacin from the microspheres decreased as thedrug/polymer ratio and the entrapment efficieney increased. Increase ın the Na-Alg content of the spheres increased the release rate.Optimum condition for the preparation and release of the spheres weredetermined as PVA/Na-Alg(w/w):1/2, crosslinker concentration:%2.5(w/v)GA+%3(w/v)HCl, drug/polymer(w/w):1/2 and pH:7,4. The release atthis condition was found as %100 at the end of 6 hour.Key Word :Poly(vinyl alcohol), Sodium alginate, Indomethacin,Gluteraldehyde, Controlled Release, Microsphere