Abstract: The manufacture of microcapsule using Gelatin-sodium Carboxymethyl Cellulose as coating material and testosterone as core material(TGM) is introduced. The average diameters of microcapsule was determined to be 29. 5 μm.The mean drug loading in microcapsule was assayed to be ( 71. 8±0.9) % for TGM. In vitrorelease show after burst release in first few days, the drugrelease from microcapsule was obeyed zero-order. The testees of male Japanese eel were achieved maturation by injection TGM at the interval of 25 d. The mean GSI of female eel were reached 19. 7% by injection TGM four times at the interval of 25 d.

Key words: gelatin-sodium carboxymethyl cellulose, microcapsule, testosterone, Japanese eel