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

CONTROLLED RELEASE OF INDOMETHACIN FROMCALCIUM CHLORIDE CROSSLINKED SODIUM ALGINATE ANDPOLY(VINYL ALCOHOL)/ SODIUM ALGINATE MICROSPHERES(M.Sc. Thesis)Ziya KABAŞGAZ UNIVERSITYINSTITUDE OF SCIENCE AND TECHNOLOGYSeptember 2006ABSTRACTIn 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 calcium chlorideand characterized by Fourier transform infrared (FTIR) spectroscopy,differential scanning calorimetry (DSC) and scanning electron microscopy(SEM). The results of SEM confirmed the spherical nature of the microspheres.Microspheres were also characterized by particle diameters, equilibriumswelling values and entrapment efficiencies and release profiles.It has been observed that percent entrapment efficiency decreased by increasingcrosslinking time and increasing crosslinker concentration. Microspherediameters decreased by increasing crosslinking time and increasing crosslinkerconcentration.The release studies were carried out that three pH volues namely 1,2; 6,8 and7,4 respectively and it was observed that as the pH of the medium increasedpercentage of cumulative release increased. It has been determined thatindomethacin release from Na-Alg microspheres and percent entrapmentefficiency increased by increasing drug/polymer ratio. Additionally byincreasing drug/polymer ratio in PVA/Na-Alg microspheres, indomethacinrelease decreased but percent entrapment efficieny increased. Moreover,increase in PVA content in microspheres, decreased the indomethacin releasebut increased the percent entrapment efficiencyOptimum condition for the preparation and release of the microspheres weredetermined as PVA/Na-Alg(w/w):l/3, crosslinker concentration: 0,5 M CaCl2,drug/polymer (w/w) :l/8 and pH:7,4. The release at this condition was found as%92 by weight at the end of 6 hours.Science Code : 201.1.117Key Words :Poly(vinyl alcohol), Sodium alginate, indomethacin,Calcium chloride, Controlled release, MicrospherePage Numbers : 88Adviser : Prof. Dr. Oya ŞANLI