水產養殖類似人類其他活動對環境有不良影響，因此應有更大的省思盡全力來保護水中生態系統。由於在水中與在魚腸道中酸鹼值的劇烈差異，本研究中我們嘗試發展酸鹼敏感性微粒來控制魚飼料釋放。魚飼料購自市場並研磨成粉，不同比例的藻酸鈉與Eudragit EP 100 溶液是作為凝集液，將魚飼料粉導入凝集液中進行微包而成為微粒，體外釋出研究是以改良式Franz 擴散槽與pH1.2 鹽酸溶液以及pH=7.0 磷酸鹽溶液進行24 小時。結果顯示，魚飼料微粒在中性環境下，可延緩釋離達12小時；微粒在酸性的環境下，最初的一小時即經酸催化水解成小粒子並釋出包覆物質。 Aquaculture, like any other human activity can have adverse effects on the environment. Hence, greater consideration is needed towards a general strategy of protecting the aquatic ecosystem at all levels. Owing to drastic variation of pH value between in water and in fish gut, we attempt to develop a pH-sensitive microparticles for controlled release of fish feed in this work. Original fish feed was bought from market and then grinded to powder. Homogenous aqueous solution of sodium alginate and Eudragit EP 100 in various ratios were used as coagulation fluid. The powder was encapsulated to form microparticle by transferring microparticles into coagulation fluid. The in vitro release study was determined over 24 hours, using modified Franz diffusion cells at HCl solution (pH=1.2) and PBS solution (pH=7.0) as a dissolution medium. The results show that the release of encapsulated microparticle can be reduced at least for 12 hours in neutral medium. Moreover, the resulting microparticles undergo acid-catalyzed hydrolysis into small parts and should therefore release encapsulated material (i.e. Vitamin B2) at an accelerated rate in acidic environments during first one hour.