SLOW RELEASE MICROCAPSULES

摘要

The inventive method for producing microcapsules is characterised in that a) in one step, liquid drops of an aqueous solution (1) containing at least one water-soluble polyanion are added to an aqueous solution (2) containing the following: 0.1 to 5 wt. % calcium cations; and 0.1 to 5 wt. % hydrolyzed chitosan with a number average molecular weight of between 2,200 and 40,000 g/mol., obtained by partial hydrolysis of a chitosan with a number average molecular weight of more than 50,000 g/mol. in an aqueous solution containing 0.1 to 4 N HCl at a temperature of between 50 and 95 DEG C for 0.5 to 8 hours, the weight ratio of the solution containing HCl to usual commercial chitosan being between 1 and 50 and the product of normality of the HCl solution and the duration of hydrolysis in hours being between 0.1 and 7; and in that b) once the addition of solution 1 is complete, the resulting microcapsules remain in solution 2 for a duration of 15 to 360 minutes, preferably 60 to 180 minutes.