| 摘要 |
PURPOSE: To obtain a sustained release spongy material composed of hyaluronic acid or its derivative and useful for microscopic surgery of otological surgery, aur-neurological surgery and dental oral surgery. CONSTITUTION: This sustained release spongy material is composed of hyaluronic acid or its derivative (especially preferably ethyl hyaluronate). The spongy material is obtained by freeze-drying an aqueous solution of hyaluronic acid or its derivative having 1-40mg/ml concentration. An aqueous solution containing hyaluronic acid or its derivative is used after filtering with a aseptized membrane having 0.2 micrometer hole. Further preferably, the aqueous solution is frozen at 0 to -90 deg.C at first and then, heated to -90 to 60 deg.C plate temperature. A freezing process is preferably carried out at a temperature-decreasing rate of 1 deg.C/20sec to 1 deg.C/3hr and sublimation process is preferably carried out at a temperature-raising rate of 1 deg.C/20sec to 1 deg.C/8hr. |
