Controlled release of salicylic acid from poly (vinyl alcohol)/sodium alginate and poly (vinyl alcohol)/chitosan microspheres

CONTROLLED RELEASE OF SALICYLIC ACID FROMPOLY (VINYL ALCOHOL) / SODIUM ALGINATE ANDPOLY (VINYL ALCOHOL) / CHITOSAN MICROSPHERES(M.Sc. Thesis)İlker KARACAGAZİ UNIVERSITYINSTITUTE OF SCIENCE AND TECHNOLOGYJanuary 2006ABSTRACTIn this study microspheres of poly (vinyl alcohol) / sodium alginate(PVA/Na-Alg), poly (vinyl alcohol) / CS (PVA/CS) were prepared to encapsulatesalicylic acid, which is a keratolik, bakteriostatik and fungusid drug.Microspheres were prepared by liquid curing method by crosslinking withgluteraldehyde They were characterized by Fourier transform infrared (FTIR)spectroscopy, differential scanning calorimetry (DSC) and scanning electronmicroscopy (SEM). SEM results confirmed the spherical nature of the particles.Microspheres were also characterized by particle diameter, equilibriumswelling values and (PVA/NA-Alg, PVA/CS) pH release profiles. Diameters ofthe different microshpheres did not show considerable difference. The releasestudies were carried at three pH values, 1,2, 6,8 and 7,4 respectively. It wasobserved that as the pH value of the release medium increased percentagecumulative drug release increased whereas microspheres of PVA/CS releasedthe drug suddenly at low pH values. When the ratio of drug/polymer decreased,the release of the drug from the microspheres of PVA/Na-Alg and PVA/CSincreased. However it was determined that, the entrapment efficiency decreasedas the ratio of drug/polymer radio decreased for both type of the microspheres.Optimum conditions for the preparation and release of the microspheres weredetermined asFor PVA/Na-Alg microspheres: PVA/Na-Alg: 3/1(w/w) crosslinkerconcentration: %2,5(v/v) GA+%3(v/v) HCI, drug/polymer(i/p): 1/1,25(w/w) andpH:7,4 In these conditions, at the end of the 6th hour total salicylic acid releasewas found as %91,40.For PVA/CS microspheres: PVA/CS: 2/1(w/w) crosslinker concentration: 1MNaOH + %2,5(v/v) GA, drug/polymer (i/p): 1/2(w/w) and pH:7,4 In theseconditions, at the end of the 6th hour total salyclic acid release was found as %85,90.Science Code: :201.1.117Key Words: :Poly (vinyl alcohol), sodium alginate, glutaraldehyde,Chitosan, salicylic acid, controlled release, microspheresPage Numbers :81Adviser :Prof. Dr. OYA ŞANLI