Ph controlled release of anticancer drug 5-fluorouracil from ionically crosslinked alginate based microspheres

In this study, microspheres of sodium alginate (NaAlg), poly(vinyl alcohol)/sodium alginate (PVA/NaAlg) and acrylamide grafted poly(vinyl alcohol)/sodium alginate (AAm-g-PVA/NaAlg) were prepared to encapsulate 5-fluorouracil which is a uracil derivative, anticancer drug. Microspheres were prepared by liquid curing method crosslinking with FeCl3, AlCl3, ZnCl2, CaCl2 and glutaraldehyde. The prepared microspheres were characterized by fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and optic microscopy. Microspheres were also characterized by particle diameter, equilibrium swelling values and release profiles. The release studies were carried out at three pH values 1,2; 6,8 and 7,4 respectively and it was observed that as the pH of the medium increased cumulative drug release increased. As the drug/polymer ratio decreased the release of 5-fluorouracil from the microspheres increased for both NaAlg and PVA-g-AAm/NaAlg microspheres, whereas entrappment efficiency has not changed considerably. Optimum conditions for the preparation and release of the microspheres were determined as PVA-g-AAm/NaAlg (w/w): 1/4, crosslinker type: FeCl3, crosslinker concentration: 0,05M, drug/polymer ratio (w/w): 1/8, crosslinking time: 10 minutes and pH: 7,4. The cumulative release at these conditions was found to be 99,57% at the end of 6 hours.