Document Detail


Drug release from lipid-based implants: elucidation of the underlying mass transport mechanisms.
MedLine Citation:
PMID:  16503388     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The aim of this study was to better understand the mass transport mechanisms involved in the control of drug release from lipid-based implants. Different types of triglyceride-based cylinders were prepared by compression. Glycerol-trilaurate, -trimyristate, -tripalmitate and -tristearate were used as model lipids, lysozyme and pyranine as model drugs. The effects of several formulation and processing parameters on the resulting drug release kinetics in phosphate buffer pH 7.4 were studied and the obtained results analyzed using Fick's second law of diffusion. Interestingly, lysozyme release from implants prepared by compression of a lyophilized emulsion (containing dissolved drug and lipid) was found to be purely diffusion-controlled, irrespective of the type of triglyceride. In contrast, the dominating release mechanism depended on the type of lipid in the case of pyranine-loaded implants prepared by compression of a lyophilized lipid-drug solution: with glycerol-trilaurate and -tristearate the systems were found to be purely diffusion-controlled, whereas also other mass transport phenomena are of importance in glycerol-trimyristate and -tripalmitate-based devices. Similarly, changes in the size of the compressed lipid-drug particles, drug loading and compression force significantly affected the underlying release mechanisms. The addition of a drug-free, poly(lactic-co-glycolic acid) (PLGA)-based coating around the implants delayed the onset of pyranine release for about 20 days. Interestingly, the subsequent drug release was purely diffusion-controlled, irrespective of the type of triglyceride. Also the addition of different amounts (and particle size fractions) of saccharose to pyranine-loaded implants led to purely diffusion-controlled drug release.
Authors:
C Guse; S Koennings; F Kreye; F Siepmann; A Goepferich; J Siepmann
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-02-28
Journal Detail:
Title:  International journal of pharmaceutics     Volume:  314     ISSN:  0378-5173     ISO Abbreviation:  Int J Pharm     Publication Date:  2006 May 
Date Detail:
Created Date:  2006-05-08     Completed Date:  2007-08-06     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7804127     Medline TA:  Int J Pharm     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  137-44     Citation Subset:  IM    
Affiliation:
College of Pharmacy, University of Regensburg, Universitaetsstr. 31, 93040 Regensburg, Germany.
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MeSH Terms
Descriptor/Qualifier:
Arylsulfonates / chemistry*,  metabolism
Biological Transport
Chemistry, Pharmaceutical
Diffusion
Drug Carriers*
Drug Implants*
Kinetics
Lactic Acid / chemistry
Lipids / chemistry*
Models, Chemical
Muramidase / chemistry*,  metabolism
Particle Size
Polyglycolic Acid / chemistry
Polymers / chemistry
Porosity
Solubility
Sucrose / chemistry
Technology, Pharmaceutical / methods
Triglycerides / chemistry
Chemical
Reg. No./Substance:
0/Arylsulfonates; 0/Drug Carriers; 0/Drug Implants; 0/Lipids; 0/Polymers; 0/Triglycerides; 0/polylactic acid-polyglycolic acid copolymer; 26009-03-0/Polyglycolic Acid; 50-21-5/Lactic Acid; 57-50-1/Sucrose; 6358-69-6/pyranine; EC 3.2.1.17/Muramidase

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


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