Controlled Release of Benzocaine from Monomer and Copolymer Carriers in Synthetic Gastro-intestinal Media

Abstract: 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. i) MA attached to ethylenic monomer (m,p-vinylbenzaldehyde), condensation reaction. ii) The copolymer carrier (Cp) is obtained by copolymerizing this monomer. 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. 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. 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: i) The cation of p-aminoniumbenzoic acid (PABAH + ) release at pH = 1,2 ii) Bz release at pH = 6,0 and 8,

Cinnamaldehyde loaded-microparticles obtained by complex coacervation: Influence of the process parameters on the morphology and the release of the core material

International audienceEncapsulation by complex coacervation includes several steps that have been developed in order to attain a better control over the whole process and to achieve an important delayed effect. This has been carried out for the encapsulation of cinnamaldehyde (CN) by the classical gelatin/acacia gum pair of coacervating polymers. This preparation was performed in different conditions (stirring speeds, cooling rate, emulsion and coacervate time, use of surfactant, and polymer concentration) in order to investigate their effect on the encapsulation efficiency and drug release kinetics. Optical microscopy studies showed spherical microcapsules. The yield of the encapsulation attains more than 88% of all prepared microcapsules. The mean Sauter diameter (d 32) of obtained microparticles was in the range from 124 to 200 µm. The microspheres were also characterized by the FTIR method; showing the presence of core and polymers in the microparticles. The release of cinnamaldehyde was performed in heterogeneous medium (Water / ethanol, v/v: 30/70) at 25±0.5°C using UV–Vis analysis. It was demonstrated that the drug release followed the Fickian diffusion mechanism. The data were best fitted to the Fick's law with high correlation coefficients (R²)