QUINTEROS Daniela Alejandra
Interaction between a cationic polymethacrylate (Eudragit E100) and anionic drugs.
DANIELA A QUINTEROS; VERÓNICA RAMIREZ RIGO; ALVARO F JIMENEZ KAIRUZ; RUBEN H MANZO; DANIEL A. ALLEMANDI
EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES
Año: 2008 p. 72 - 72
The interaction between a cationic polymethacrylate (Eudragit® E, EU) and a set of 7 drugs having acid groups (AH) was studied. Two series of complexes were prepared (EUAH50 and EUAH50Cl50), in both 50% of the basic groups of EU were neutralized with AH but in the second, the remaining groups were further neutralized with HCl. These products were stable solid ionic complexes that were characterized through infrared spectroscopy and X-ray power diffraction. All EUAH50Cl50 at 510 mg/ml produced clear optically isotropic aqueous dispersions. This result was in line with the increase of the apparent solubility of the low solubility AH assayed. The species distribution, as determined on the complex of diclofenac, showed a degree of counterion condensation as high as 97.9%. The reversibility of the counterion condensation, as well as the afﬁnity between EU and AH, was evaluated through the proton withdrawing effect produced by the ionic exchange generated by titration with NaCl. Besides, drug delivery in bicompartimental Franz cells towards water as receptor medium was very slow. However, it was increased as water was replaced by NaCl solution that upon diffusion generates ionic exchange. Therefore, the EUAH system behaves as a reservoir of drug able to deliver it in simulated biological ﬂuid