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Estimation of the percolation thresholds in ternary lobenzarit disodium–dextran–HPMC hydrophilic matrices tablets: Effects of initial porosity

Castellanos Gil, Eddy and Iraizoz Colarte, Antonio and Bataille, Bernard and Brouillet, Fabien and Caraballo, Isidoro Estimation of the percolation thresholds in ternary lobenzarit disodium–dextran–HPMC hydrophilic matrices tablets: Effects of initial porosity. (2009) European Journal of Pharmaceutical Sciences, 38 (4). 312-319. ISSN 0928-0987

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Official URL: https://doi.org/10.1016/j.ejps.2009.07.013

Abstract

The aim of this work is to estimate the excipient percolation threshold for a new combined matrix native dextran (DT), series B110-1-2 (Mw 2×106): HPMC K4M CR: lobenzarit disodium (LBD) system and demonstrate the advantages of this ternary system with respect to previously reported binary dextran:LBD and HPMC:LBD tablets. The formulations studied were prepared with different amounts of excipient (DT:HPMC, 4:1 (wt/wt) for all tablets and relative polymer/drug particle size of 4.17) in the range of 10–70% (wt/wt). Dissolution studies were carried out using the paddle method (100rpm) and one face water uptake measurements were performed using a modified Enslin apparatus. The Higuchi's models as well as the non-linear regression were employed as empiric methods to study the released data. Values of diffusion exponent 0.588<n<0.784 (Korsmeyer equation) for dissolution profile and water uptake mechanism 0.715<n<0.960 (Davidson and Peppas equation) suggests anomalous or complex mechanisms in all cases. The critical points in ternary tablets were reduced from 44.75% (v/v) of excipient (correspond to purely native dextran) to 22.34% (v/v) (corresponding to mixture native dextran:HPMC, 4:1, wt/wt). The initial porosity (IP) of hydrophilic matrices above the values of 20% has an important influence on the percolation threshold as well as on establishment of the gel barrier responsible for the controlled release from the DT:HPMC:LBD tablets.

Item Type:Article
HAL Id:hal-00610199
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Universidad de La Habana - UH (CUBA)
Other partners > Université de Montpellier 1 (FRANCE)
Other partners > Universidad de Sevilla (SPAIN)
Funders:
European Union Programme Alßan
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Deposited By: Yves MOMBOISSE
Deposited On:16 Oct 2019 14:26

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