Due to similarity in composition to the mineral component of bones and human hard tissues. hydroxyapatite with chemical formula Ca10(PO4)6(OH)2 has been widely used in medical field. Both chicken and duck eggshells are mainly composed of calcium carbonate. An attempt has been made to fabricate nanohydroxyapatite (nHA) by chicken (CES) and duck eggshells (DES) as calcium carbonate sour... https://www.chiggate.com/aptamil-allerpro-syneo-2-900g-online-now/