Doxazosin-carrageenan interactions: a novel approach for studying drug-polymer interactions and relation to controlled drug release.

摘要: Abstract When a cationic drug like doxazosin mesylate (DM) is incorporated into matrix tablets made of anionic polyelectrolytes carrageenans (CARRs) different types (κ-, ι-, λ-CARR), DM–CARR interactions have strong impact on release. To investigate these interactions, special DM ion-selective membrane electrode was and applied for construction binding isotherms. Isotherms were treated by the Zimm–Bragg theory cooperative model. It demonstrated that cations, DH + , to CARRs cooperative. starts at very low concentrations with electrostatic followed aggregation ions. Hydrophobic between bound substantially contribute extent binding. The strength increases increasing negative charge CARRs. At saturation, number molecules per repeat unit depends steric distribution sites Drug release rates from CARR matrices in accordance cooperativity constants: weakest resulted fastest However it proven prolonged possible only several processes running simultaneously, i.e., swelling erosion one side effects other.