Related Experiment Video
Updated: May 13, 2026

Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites
Published on: September 19, 2020
Critical points in ethylcellulose matrices: influence of the polymer, drug and filler properties
Celia Cifuentes1, Angela Aguilar-de-Leyva, Ali R Rajabi-Siahboomi
1Department of Pharmacyand Pharmaceutical TechnologyUniversity of Seville, Seville, Spain.
Abstract:
Percolation theory has been applied to study the drug release behaviour in multicomponent inert matrices containing ethylcellulose as a matrix forming polymer. Global influence of major formulation factors such as polymer viscosity, polymer particle size, drug and filler solubility and porosity of the tablets in drug release kinetics has been studied for the first time. Batches containing three viscosity grades of Ethocel™, microcrystalline cellulose (MCC) and lactose as fillers, a lubricant and flow aid mixture and three drugs with different solubility have been manufactured. For some batches, compression pressure was varied in order to obtain matrices with five levels of initial porosity. The behaviour of inert matrices was explained based on the percolation ranges of the main components of the formulation. The effect of the porosity percolation threshold was observed and the existence of a tricoherent drug-polymer-filler system is hypothesized.
Related Concept Videos
Factors Influencing Drug Absorption: Pharmaceutical Parameters
Factors Affecting Dissolution: Polymorphism, Amorphism and Pseudopolymorphism
Some polymorphic crystals possess lower aqueous solubility than their amorphous counterparts, leading to incomplete absorption. For instance, the oral suspension of Chloramphenicol, which...
Pharmaceutical Alternatives: Polymorphic Form-Related and Particle Size-Related Therapeutic Nonequivalence
Factors Affecting Dissolution: Drug Permeability, Stability and Stereochemistry
Bioavailability Enhancement: Drug Stability Enhancement and GI Retention
Formulation and Manufacturing Process: Physical Attributes of Generic Tablets and Capsules

