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Study of the critical points of HPMC hydrophilic matrices for controlled drug delivery.
Int J Pharm. 2006 Mar 27; 311(1-2):75-81.IJ

Abstract

The knowledge of the percolation thresholds of a system results in a clear improvement of the design of controlled release dosage forms such as inert matrices. Despite hydrophilic matrices are one of the most used controlled delivery systems in the world, but actuality, the mechanisms of drug release from these systems continue to be a matter of debate nowadays. The objective of the present paper is to apply the percolation theory to study the release and hydration rate of hydrophilic matrices. Matrix tablets have been prepared using KCl as a drug model and HPMC K4M as matrix-forming material, employing five different excipient/drug particle size ratios (ranging from 0.42 to 2.33). The formulations studied containing a drug loading in the range of 20-90% (w/w). Dissolution studies were carried out using the paddle method and the water uptake measurements were performed using a modified Enslin apparatus. In order to estimate the percolation threshold, the behaviour of the kinetic parameters with respect to the volumetric fraction of each component at time zero, was studied. The percolation theory has been applied for the first time to the study of matrix type controlled delivery systems. The application of this theory allowed to explain changes in the release and hydration kinetics of these matrices. The critical points observed in dissolution and water uptake studies can be attributed to the excipient percolation threshold, being this threshold one of the main factors governing the gel layer formation and consequently, the drug release control from hydrophilic matrices.

Authors+Show Affiliations

Miranda A
Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain. amirandal@us.es
Millán M
No affiliation info available
Caraballo I
No affiliation info available

MeSH

Chemistry, PharmaceuticalDelayed-Action PreparationsExcipientsHypromellose DerivativesKineticsMethylcelluloseModels, ChemicalParticle SizePotassium ChlorideSolubilityTabletsWater

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16446063

Citation

Miranda, Antonia, et al. "Study of the Critical Points of HPMC Hydrophilic Matrices for Controlled Drug Delivery." International Journal of Pharmaceutics, vol. 311, no. 1-2, 2006, pp. 75-81.
Miranda A, Millán M, Caraballo I. Study of the critical points of HPMC hydrophilic matrices for controlled drug delivery. Int J Pharm. 2006;311(1-2):75-81.
Miranda, A., Millán, M., & Caraballo, I. (2006). Study of the critical points of HPMC hydrophilic matrices for controlled drug delivery. International Journal of Pharmaceutics, 311(1-2), 75-81.
Miranda A, Millán M, Caraballo I. Study of the Critical Points of HPMC Hydrophilic Matrices for Controlled Drug Delivery. Int J Pharm. 2006 Mar 27;311(1-2):75-81. PubMed PMID: 16446063.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Study of the critical points of HPMC hydrophilic matrices for controlled drug delivery. AU - Miranda,Antonia, AU - Millán,Mónica, AU - Caraballo,Isidoro, Y1 - 2006/01/30/ PY - 2005/07/27/received PY - 2005/11/10/revised PY - 2005/12/09/accepted PY - 2006/2/1/pubmed PY - 2006/10/17/medline PY - 2006/2/1/entrez SP - 75 EP - 81 JF - International journal of pharmaceutics JO - Int J Pharm VL - 311 IS - 1-2 N2 - The knowledge of the percolation thresholds of a system results in a clear improvement of the design of controlled release dosage forms such as inert matrices. Despite hydrophilic matrices are one of the most used controlled delivery systems in the world, but actuality, the mechanisms of drug release from these systems continue to be a matter of debate nowadays. The objective of the present paper is to apply the percolation theory to study the release and hydration rate of hydrophilic matrices. Matrix tablets have been prepared using KCl as a drug model and HPMC K4M as matrix-forming material, employing five different excipient/drug particle size ratios (ranging from 0.42 to 2.33). The formulations studied containing a drug loading in the range of 20-90% (w/w). Dissolution studies were carried out using the paddle method and the water uptake measurements were performed using a modified Enslin apparatus. In order to estimate the percolation threshold, the behaviour of the kinetic parameters with respect to the volumetric fraction of each component at time zero, was studied. The percolation theory has been applied for the first time to the study of matrix type controlled delivery systems. The application of this theory allowed to explain changes in the release and hydration kinetics of these matrices. The critical points observed in dissolution and water uptake studies can be attributed to the excipient percolation threshold, being this threshold one of the main factors governing the gel layer formation and consequently, the drug release control from hydrophilic matrices. SN - 0378-5173 UR - https://www.unboundmedicine.com/medline/citation/16446063/Study_of_the_critical_points_of_HPMC_hydrophilic_matrices_for_controlled_drug_delivery_ DB - PRIME DP - Unbound Medicine ER -