title: Drug release kinetics and front movement in matrix tablets containing diltiazem or metoprolol/λ-carrageenan complexes.
abstract: In this work we investigated the moving boundaries and the associated drug release kinetics in matrix tablets prepared with two complexes between λ-carrageenan and two soluble model drugs, namely, diltiazem HCl and metoprolol tartrate aiming at clarifying the role played by drug/polymer interaction on the water uptake, swelling, drug dissolution, and drug release performance of the matrix. The two studied complexes released the drug with different mechanism indicating two different drug/polymer interaction strengths. The comparison between the drug release behaviour of the complexes and the relevant physical mixtures indicates that diltiazem gave rise to a less soluble and more stable complex with carrageenan than metoprolol. The less stable metoprolol complex afforded an erodible matrix, whereas the stronger interaction between diltiazem and carrageenan resulted in a poorly soluble, slowly dissolving matrix. It was concluded that the different stability of the studied complexes affords two distinct drug delivery systems: in the case of MTP, the dissociation of the complex, as a consequence of the interaction with water, affords a classical soluble matrix type delivery system; in the case of DTZ, the dissolving/diffusing species is the complex itself because of the very strong interaction between the drug and the polymer.
authors.affiliation: Department of Pharmacy, University of Parma, Parco delle Scienze 27/A, 43124 Parma, Italy.
authors.forename: Ruggero
authors.identifier: 0000-0002-3857-7476
authors.initials: R
authors.lastname: Bettini
authors.affiliation: Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Bonferoni
authors.affiliation: Department of Pharmacy, University of Parma, Parco delle Scienze 27/A, 43124 Parma, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Colombo
authors.affiliation: Department of Pharmacy, University of Parma, Parco delle Scienze 27/A, 43124 Parma, Italy ; Eratech Srl, Via Gandine 4, 29121 Piacenza, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Zanelotti
authors.affiliation: Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Caramella
mesh_terms: D002351:Carrageenan / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000737:chemistry; D004110:Diltiazem / Q000008:administration & dosage / Q000737:chemistry*; D016503:Drug Delivery Systems; D065546:Drug Liberation; D006801:Humans; D008790:Metoprolol / Q000008:administration & dosage / Q000737:chemistry*; D010599:Pharmacokinetics; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry; D012995:Solubility; D013607:Tablets; D014867:Water / Q000737:chemistry
chemical_list: D003692:Delayed-Action Preparations; D011108:Polymers; D013607:Tablets; D014867:Water; D002351:Carrageenan; D004110:Diltiazem; D008790:Metoprolol