Diffusion Transport Properties of Polymeric Complex Matrix Systems Based on Eudragit E and Sodium Alginate

Abstract

The search for new polymeric carriers intended for the development of controlled-release drugs is of considerable importance for the pharmaceutical science and technology. A promising basis for solving this task is offered by so-called interpolyelectrolyte complexes (IPCs). The unique properties of these compounds established as a result of extensive physicochemical investigations allowed them to be considered as a special class of polymeric carriers. IPCs are synthesized via interaction of two oppositely charged polyelectrolytes: polycations and polyanions [1]. According to published data, IPCs used as drug carriers possess unique diffusion transport characteristics. This is related to the advantageous structure of IPCs, which can be modified in a controlled manner through modification of the macromolecular parameters of the polymeric components of IPCs [2 – 4]. Taking into account these advantages of IPCs (which provide for the possibility of solving almost any problem encountered in the creation of peroral drugs), we have studied the most frequently applied polymers produced by Roehm Pharma (Germany) on the basis of copolymers of acrylic acid (AA) and poly(methyl methacrylate) (PMMA) under the trade name Eudragit. Taking into account that these copolymers are polyelectrolytes, we attempted to modify the Eudragit structure by including it into an ICP with an oppositely charged polymer. As a result, we obtained new IPCs based on the gastrosoluble component Eudragit E (polycation) and the natural polysaccharide sodium alginate (Na-AL) (polyanion). Preliminarily, we have studied the conditions of formation of polymeric complexes based on the selected pair of polyelectrolytes. We used the methods of turbidimetric titration, viscometry, elemental analyses (for determining the composition of IPCs), and IR and differential scanning calorimetry (for determining the structure of complexes). This paper reports on the results of investigation of the diffusion transport properties of Eudragit E100sodium