MULTICHAMBER GASTROINTESTINAL DIFFUSION SYSTEM CONTAINING ISOSORBIDE 5-MONONITRATE

In the method of preparation of diffusion membranes, it is more effect ive to use aqueous dispersions for this purpose than to coat with solu tions of polymers in organic solvents. This procedure allows organic s olvents to be eliminated which is of importance for the protection of human beings and environment. In the present paper, a method of coatin g microballscores containing isosorbide 5-mononitrate (1) has been dev eloped with aqueous dispersions of ethyl cellulose and Eudragit(R) L-1 00, in order to prepare a Multichamber Gastrointestinal Diffusion Syst em (MGDS). The controlled release rate of the drug from the system ove r a longer period of time is insured by an appropriate plasticizer in the membrane composition. Based on in vitro experiments which investig ated the release of 1 from various systems which differed in the thick ness of the membrane and the size of cores, system VIII has been selec ted as the most effective. The system releases approx. 92% of 1 over 7 h with the average constant rate K0 = 6.18 +/- 0.64 mg . h-1.