<p class="Default">New dosage forms able to control drug release in the gastro-intestinal media have been prepared and investigated in this paper. Two different type of medicinal agent bonding (MA), in our case Benzocaine (Bz), were chosen in order to examine drug release.</p><p class="Default">i) MA attached to ethylenic monomer (m,p-vinylbenzaldehyde), condensation reaction.</p><p class="Default">ii) The copolymer carrier (Cp) is obtained by copolymerizing this monomer.</p><p class="Default">These two carriers were well characterized by microanalysis, FTIR, DSC (Tg) and GPC (Ip) and the two fraction α and β were calculated from elemental analyses of Cp. The results showed good polydispersity and low average molecular weight. MA linked to an organic product by the azomethine function (C=N), hydrolytically sensitive, allowed controlled release of Bz, from the monomer carrier and from the bending Schiff bases groups. Theoretical and experimental analyses of controlled release of Bz kinetics from monomer and copolymer carriers were conducted for the case of contact with synthetic gastro-intestinal fluids at various pH (1,2; 6,0 and 8,0) at 37°C.</p><p class="Default">The process was found to be controlled by the nature of media (heterogeneous), which involved the preliminary hydrolysis, and the drug (Bz) diffusing out of structure of copolymer (Cp) to the external aqueous media.</p><p class="Default">The results obtained on the rate of delivery showed a clear difference between pH = 1,2 and pH = 6,0 and 8,0 based on:</p><p class="Default">i) The cation of p-aminoniumbenzoic acid (PABAH+) release at pH = 1,2</p><p class="Default">ii) Bz release at pH = 6,0 and 8,0</p>