Characterisation of drug loaded insoluble polymeric matrices prepared by hot melt extrusion technology for drug delivery applications.
type: CreativeWork
description: The main aim of this research was to manufacture and characterise the physiochemical, rheological and drug release properties of drug loaded insoluble matrices prepared by HME technology, to provide a deeper understanding of the mechanisms which affect drug release from hot melt extruded solid dosage forms. Polymethacrylate polymers are frequently used within the pharmaceutical industry as film coating agents many of which offering unique pH-solubility profiles for targetted drug delivery. Eudragit RL PO and RS PO are insoluble polymers which remain intact across the physiological pH range and represent a largely understudied category of materials as polymeric matrices for drug delivery. The physical and chemical characteristics of Eudragit RL PO were investigated showing good thermal stability at processing temperatures below 180°C. Above 180°C, thermal decomposition proceeded by a mechanism which caused cleavage and subsequent loss of ammonio methacrylate functional groups. Eudragit RL PO exhibited hygroscopic properties containing approximately 3% adsorbed residual moisture when stored at ambient temperature at atmospheric conditions. Acceptable processing limits for hot melt extrusion of Eudragit RL PO were defined with an optimal temperature window between 120°C and 170°C and screw speed between 100 and 150rpm. Adsorbed water vapour above 60% relative humidity acted as a plasticizer for Eudragit'4 RL PO which lowered the glass transition to below ambient temperature causing an increase in permeability of the material, prompting recommendations for storage of amorphous drug dispersions with a desiccant to prevent the ingress of moisture and improve solid sate stability. Modelling of the water uptake kinetics of extruded polymer samples showed that the polymer exhibited anomalous non-Fickian transport behaviour where the rate of inward diffusion was approximately equal to the rate of polymer chain relaxation. Water ingress resulted in plasticization of the polyme…
abstract: The main aim of this research was to manufacture and characterise the physiochemical, rheological and drug release properties of drug loaded insoluble matrices prepared by HME technology, to provide a deeper understanding of the mechanisms which affect drug release from hot melt extruded solid dosage forms. Polymethacrylate polymers are frequently used within the pharmaceutical industry as film coating agents many of which offering unique pH-solubility profiles for targetted drug delivery. Eudragit RL PO and RS PO are insoluble polymers which remain intact across the physiological pH range and represent a largely understudied category of materials as polymeric matrices for drug delivery. The physical and chemical characteristics of Eudragit RL PO were investigated showing good thermal stability at processing temperatures below 180°C. Above 180°C, thermal decomposition proceeded by a mechanism which caused cleavage and subsequent loss of ammonio methacrylate functional groups. Eudragit RL PO exhibited hygroscopic properties containing approximately 3% adsorbed residual moisture when stored at ambient temperature at atmospheric conditions. Acceptable processing limits for hot melt extrusion of Eudragit RL PO were defined with an optimal temperature window between 120°C and 170°C and screw speed between 100 and 150rpm. Adsorbed water vapour above 60% relative humidity acted as a plasticizer for Eudragit'4 RL PO which lowered the glass transition to below ambient temperature causing an increase in permeability of the material, prompting recommendations for storage of amorphous drug dispersions with a desiccant to prevent the ingress of moisture and improve solid sate stability. Modelling of the water uptake kinetics of extruded polymer samples showed that the polymer exhibited anomalous non-Fickian transport behaviour where the rate of inward diffusion was approximately equal to the rate of polymer chain relaxation. Water ingress resulted in plasticization of the polyme…
author: Caldwell, Deborah
language: eng
date published: 2012-7
date modified: 2026-07-24T03:54:59Z
provider: Queen's University Belfast
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Queen's University Belfast