Linked Life Data

9423163

Source:http://linkedlifedata.com/resource/pubmed/id/9423163

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
1998-2-26
pubmed:abstractText
A theoretical model is outlined for predicting the time evolution of total mass, mean molecular weight, and drug release for the case of a spherical bulk-eroding microsphere, prepared by a double emulsification procedure and containing a hydrophilic drug, such as a protein or peptide. Explicit analytical formulae are derived for calculating the time evolution of measurable macroscopic characteristics, such as drug release or mean molecular weight. Microsphere hydration, polymer erosion, and drug release phases are each described. Results indicate that polymer degradation by only random-chain scission or only end scission (or unzipping) cannot explain experimentally observed kinetics of particle mass loss and molecular weight change; thus, a combined model (incorporating both random and end scission) is proposed. A general methodology for determining the microscopic transport coefficients (such as polymer degradation rate constant or drug diffusion coefficient) from erosion and release data is outlined. This paradigm is applied to the specific case of 50:50 poly(D,L-lactic-co-glycolic acid (PLGA) microspheres encapsulating glycoprotein 120 (gp 120), a candidate AIDS vaccine. Predictions permit comparisons with experimental data for mean weight- and number-averaged molecular weights, as well as for mass loss and protein release. Other comparisons are made with data appearing in the literature for release of tetanus toxoid from PLA and PLGA microspheres of variable molecular weight. Agreement between theory and experiment is observed.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-3549
pubmed:author
pubmed:issnType
Print
pubmed:volume
86
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1464-77
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
A theoretical model of erosion and macromolecular drug release from biodegrading microspheres.
pubmed:affiliation
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't