Crystallized carbohydrate spheres for slow release and targeting

Crystallized carbohydrate spheres have been prepared for use as a matrix for entrapment of biologically active substances, such as insulin, interferon, and growth hormone, which, when released, retain their biological activities, and where the carbohydrates are well known with documented low toxicity in human, as well as in the veterinary medical fields. The crystallized carbohydrate spheres containing entrapped antigens with co-entrapped immunomodulators may also be considered as a possible matrix of choice in immunization with weak antigens in humans, where the adjuvant effect presumably is a combination of slow release and macrophage stimulation, which is due to the small size of the spheres. By co-entrapment of magnetite particles it is possible to target magnetically responsive carbohydrate microspheres to the brain, for example, or any other area in the body, thus promoting higher concentration of drug in the target area. The method of preparation, using the high-pressure homogenization technique, is easily scaled up, and with the use of commercially available devices, one could easily fabricate tons of the CCS per day. Release of the entrapped substances probably occurs via erosion of the matrix, rendering degradation products that are nonmodified as compared to the starting material. A further advantage of this concept is that there is no enzymatic degradation of the matrix influencing the release, since the parameters capable of breaking the hydrogen bonds stabilizing the crystallized structure are mainly pH and ionic strength, both of which are stable in a human body.