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A mechanistic interpretation of the zero order release from pendent chain‐linked glassy and swollen hydrogels
Author(s) -
Shah S. S.,
Kulkarni M. G.,
Mashelkar R. A.
Publication year - 1990
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1990.070410943
Subject(s) - self healing hydrogels , active ingredient , penetrant (biochemical) , zero order , swelling , dissolution , polymer chemistry , materials science , chemical engineering , polymer , hydrolysis , chemistry , organic chemistry , composite material , first order , bioinformatics , mathematics , engineering , biology
Zero order release of active ingredients, physically dispersed in the glassy hydrogels has been ascribed in the past to the case II transport of the penetrant medium into the glassy matrix (phase erosion). Surface erosion of the polymer by dissolution has also been shown to result in the zero order release of the dispersed/dissolved active ingredient. This communication reports the zero order release of the pendent chain‐linked p ‐nitro benzoic acid and 2,4‐dinitro benzoic acid from glassy as well as swollen hydrogel matrices. The results have been elucidated on the basis of increase in the diffusivity of the active ingredient released by hydrolysis and the concomitant increase in the degree of swelling of the polymer matrix. This is the first reported finding of zero order release of an active ingredient from the matrix device as a result of bulk erosion.