Patent ID: 6552184
Filing Date: 2003-04-22
Classification: C08B,C08L,Y02P

Abstract:
Process for the preparation of autocrosslinked compounds of hyaluronic acid and derivatives thereof by the technique of precipitation induced by antisolvent, comprising the following steps:a) preparing solutions of the quaternary ammonium salt of hyaluronic acid or derivatives thereof and a crosslinking agent; b) loading the solutions of quaternary ammonium salt and crosslinking agent container being fitted with a pump to suck up the liquid; c) adjusting the rotation speed to within a range of 200-1000 rpm; d) adjusting the temperature to within a range of âˆ’20 to 20Â° C.; e) adjusting the pressure of the fluid to below that required for precipitation of the quaternary ammonium salt of hyaluronic acid or derivatives thereof; f) injecting the solution of crosslinking agent into the precipitator at a pressure that is greater than that in the precipitator; g) optionally, injecting a buffer solution into the precipitator; h) increasing the temperature to a value within a range of 20 to 50Â° C.; i) leaving it to react for between 2 and 12 hours; j) washing the product with a flow of antisolvent at a pressure of between 60 and 150 bar; k) depressurizing and harvesting the product.