New Carriers for Bioadhesive Gastroretentive Drug Delivery Systems Based on Eudragit® EPO/Eudragit® L100 Interpolyelectrolyte Complexes

Abstract

Interpolyelectrolyte complexes Eudragit® EPO/L100 received in different pH were characterized by different degree of swelling in mimicking fasted stomach medium (0.1 M HCl) and saved their shape during 6 hours of the experiment. The microenvironmental changes in IPECs structure during swelling testing were inves-tigated using FT-IR spectroscopy, thermal and elemental analysis. Both samples of IPECs during swelling were transformed to a similar structure with approximately the same composition. IPEC samples showed bioadhesive properties that was not significantly different from the positive control (Carbopol) in the test with the mucin compacts. The release rate of metronidazole (class I BCS) from IPEC matrices increased with the increasing degree of swelling. IPEC 1 provided 49.62 ± 6.20% and IPEC 2 – 87.69 ± 5.15 % of metronidazole release after 6 hours in mimicking fasted stomach medium (0.1 M HCl). Total amount of released acyclovir (class III BCS) from IPEC 1 was 25.76 ± 5.67 % and from IPEC 2 was 21.48 ± 5.00 %. Release of both drugs was controlled by relaxation of polymeric chains in matrices according to the Peppas-Sahlin model. According to the received results, investigated interpolymer complexes are perspective for further evalua-tion as carriers for gastroretentive bioadhesive systems.