Release study of methylene blue (as drug model) by alginate-gelatin blend macrospheres prepared via crosslinking method

This study focuses on the preparation of alginate-gelatin blend macrospheres for the encapsulation and release of methylene blue as a model drug. The macrospheres were prepared by crosslinking sodium alginate and gelatin polymers with calcium chloride. The alginate-gelatin ratios used were 20:80, 35:65 and 50:50. The formed beads were characterized by Fourier Transform Infrared (FTIR) spectroscopy, UV-visible spectrophotometry and optical microscopy. The effects of polymer ratio, crosslinker concentration, needle gauge size and release medium pH on the drug release profiles were investigated. FTIR analysis confirmed the presence of specific functional groups indicating crosslinking between the polymers. The microscopy and particle size analyses revealed round smooth beads with diameters ranging from 6-10 mm based on the needle gauge used. The UV-vis studies demonstrated controlled and sustained methylene blue release for up to 60 minutes from the macrosphere formulations. A slower drug release pattern was achieved at neutral pH 7 compared to acidic pH 4 and basic pH 9. The results indicate that tailored alginate-gelatin blend macrospheres prepared by crosslinking can serve as efficient systems for the encapsulation and controlled release of drugs.