Formulation and characterization of α-mangostin in chitosan nanoparticles coated by sodium alginate, sodium silicate, and polyethylene glycol oleh Nasrul Wathoni, Agus Rusdin, Erma Febriani, Destiana Purnama, Wahnidar Daulay, Sundoro Y Azhary, Camellia Panatarani, I Made Joni, Ronny Lesmana, Keiichi Motoyama, Muchtaridi Muchtaridi