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.

Chitosan and Kappa-Carrageenan Vaginal Acyclovir Formulations for Prevention of Genital Herpes. In Vitro and Ex Vivo Evaluation

“…The formulation containing the highest ratio of kappa-carrageenan (CKH1) released 100% of ACV in 120 h, whereas the CKH2 formulation required 192 h to release all of the drug. This may be the result of the ability of the kappa-carrageenan compacts to erode, as has been described by Bettini et al [ 32 ] for the metoprolol/λ-carrageenan matrix. The chitosan-based compacts showed a strong interaction between chitosan and HPMC, and a more controlled release of ACV, regardless of the chitosan/HPMC ratio.…”

Ambroxol Hydrochloride Loaded Gastro-Retentive Nanosuspension Gels Potentiate Anticancer Activity in Lung Cancer (A549) Cells

“…NA and CRG K were added to slow the ABX-CRGK complex dissociation, and CS served as a cross-linking agent. Different formulations were selected to check the impact of CS removal (F1), CRG K removal (F2), SA solid particles usage instead of its solution (F3), and the impact of combining the CRG K , CS, and SA solution to form F4 [ 26 , 27 ]. Furthermore, the selection and optimization of the SA, CS, and CRGK grades and amounts were based on having the ABX particles released as nanoparticles from the polymeric raft/floating gel [ 25 , 27 ].…”

Sulfated Seaweed Polysaccharides as Multifunctional Materials in Drug Delivery Applications

“…It was observed that different drugs give complexes with quite different characteristics of solubility and drug release kinetics. In another approach, carrageenan was associated with two drug models, diltiazem HCl and metoprolol tartrate, and the two studied complexes released the drug with different mechanism indicating two different drug/polymer interaction strengths (stronger interaction with diltiazem) [ 259 ]. Other recent developments included the use of carrageenan, combined with other matrix materials, to associate and release vitamin B2 [ 260 ] and lisinopril [ 261 ].…”