Preparation and physical characterization of andrographolide-chitosan-alginate microparticles prepared by ionic gelation-freeze drying

This study aimed to determine the effect of alginate concentration on physical characterization (morphology, physical state, and encapsulation efficiency) of andrographolide-chitosan-alginate microparticles prepared by ionic gelation- freeze drying method. Andrographolide-chitosan-alginate microparticles were produced with various amount of alginate by ionic gelation method using tripholyphospate (TPP) as crosslinker and maltodextrin as a lyoprotectant. The physical characteristics were evaluated using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrophotometer (FT-IR), Differential Thermal Analyzer (DTA), Powder X-ray diffractrometer (PXRD), drug content was evaluated using High Pressure Liquid Chromatography (HPLC). The results showed that andrographolide crystallinity changed after encapsulated inside the microparticles supported by changes in IR spectra, and melting point. Furthermore, increased alginate concentration showed rougher surface morphology. The amount of alginate affected the characteristics of the andrographolide-chitosan-alginate microparticles by altering the crystallinity and lowering melting point. The highest encapsulation efficiency shown by microparticles with 0.5% alginate.