Document Detail

Ethylene vinyl acetate as matrix for oral sustained release dosage forms produced via hot-melt extrusion.
MedLine Citation:
PMID:  21168487     Owner:  NLM     Status:  In-Data-Review    
Different ethylene vinyl acetate grades (EVA9, EVA15, EVA28 and EVA40 having a VA content of 9%, 15%, 28% and 40%, respectively) were characterized via differential scanning calorimetry. Glass transition temperature (T(g)), polymer crystallinity, melting point and polymer flexibility were positively influenced by the vinyl acetate content. The processability of EVA-based formulations produced by means of hot-melt extrusion (2mm die) was evaluated in function of VA content, extrusion temperature (60-140°C) and metoprolol tartrate (MPT, used as model drug) concentration (10-60%). Matrices containing 50% MPT resulted in smooth-surfaced extrudates, whereas at 60% drug content severe surface defects (shark skinning) were observed. Drug release from EVA/MPT matrices (50/50, w/w) was affected by the EVA grades: 90% after 24h for EVA15 and 28, while EVA9 and EVA40 formulations released 80% and 60%, respectively. Drug release also depended on drug loading and extrusion temperature. For all systems, the total matrix porosity (measured by X-ray tomography) was decreased after dissolution due to elastic rearrangement of the polymer. However, the largest porosity reduction was observed for EVA40 matrices as partial melting of the structure (melt onset temperature: 34.7°C) also contributed (thereby reducing the drug release pathway and yielding the lowest release rate from EVA40 formulations). The Simulator of the Human Intestinal Microbial Ecosystem (SHIME) used to evaluate the stability of EVA during gastrointestinal transit showed that EVA was not modified during GI transit, nor did it affect the GI ecosystem following oral administration.
A Almeida; S Possemiers; M N Boone; T De Beer; T Quinten; L Van Hoorebeke; J P Remon; C Vervaet
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Publication Detail:
Type:  Journal Article     Date:  2010-12-17
Journal Detail:
Title:  European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft für Pharmazeutische Verfahrenstechnik e.V     Volume:  77     ISSN:  1873-3441     ISO Abbreviation:  Eur J Pharm Biopharm     Publication Date:  2011 Feb 
Date Detail:
Created Date:  2011-01-31     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9109778     Medline TA:  Eur J Pharm Biopharm     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  297-305     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier B.V. All rights reserved.
Laboratory of Pharmaceutical Technology, Ghent University, Ghent, Belgium.
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