Document Detail

Properties of enteric coated sodium valproate pellets.
MedLine Citation:
PMID:  12972338     Owner:  NLM     Status:  MEDLINE    
The influence of subcoat application and micro-environmental pH on the dissolution properties of enteric coated sodium valproate pellets was investigated. The pellets were prepared by solution-layering or wet-mass extrusion-spheronization methods. In order to pass the USP enteric test, the solution-layered and wet-mass extruded pellets required 35 and 25% weight gain of Eudragit L 30D-55, respectively. The application of a subcoat of either Methocel-E5 (HPMC) or Opadry AMB to the pellets resulted in a delay in sodium valproate release in 0.1N HCl. Further delay in drug release was observed when citric acid was present in a HPMC subcoat or when added to the core pellet formulation. The amount of drug released from coated pellets was a function of the level of citric acid in the pellet core or subcoat and subsequent micro-environmental pH of the pellets. Citric acid exerted a plasticizing effect on the enteric polymer film and improved film formation and polymer coalescence. When greater than 10% (w/w) citric acid was present in the pellets, a decrease in drug content was observed due to the conversion of sodium valproate to the volatile compound, valproic acid. Pellets containing less than 10% (w/w) citric acid maintained potency during processing.
L Diane Bruce; Hans-Ulrich Petereit; Thomas Beckert; James W McGinity
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  International journal of pharmaceutics     Volume:  264     ISSN:  0378-5173     ISO Abbreviation:  Int J Pharm     Publication Date:  2003 Oct 
Date Detail:
Created Date:  2003-09-15     Completed Date:  2004-02-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7804127     Medline TA:  Int J Pharm     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  85-96     Citation Subset:  IM    
Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, USA.
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MeSH Terms
Anticonvulsants / chemistry*
Chemistry, Pharmaceutical
Citric Acid / chemistry
Drug Compounding
Drug Delivery Systems
Excipients / chemistry
Hydrogen-Ion Concentration
Mass Spectrometry
Methacrylates / chemistry
Microscopy, Electron, Scanning
Polymers / chemistry
Tablets, Enteric-Coated
Time Factors
Valproic Acid / chemistry*
Water / chemistry
Reg. No./Substance:
0/Anticonvulsants; 0/Eudragit L 30 D-55; 0/Excipients; 0/Methacrylates; 0/Polymers; 0/Tablets, Enteric-Coated; 77-92-9/Citric Acid; 7732-18-5/Water; 99-66-1/Valproic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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