Hetrocyclic methacrylate systems as vehicles for the release of active species.
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The room temperature polymerising heterocyclic polymer system, poly(ethyl
methacrylate)/tetrahydrofurfuryl methacrylate (PEM/THFM) has been shown
previously to be biocompatible and supported tissue repair, specifically for bone
and cartilage, and biologically inert when in contact with the dental pulp. It
proved more effective, than other glassy methacrylates in the release of active
species.
The PEM/THFM system is a rigid material. The aim of this study was to develop
and characterise the use of this system as a flexible patch, for application and
retention to the buccal mucosa, thus facilitating sustained regulated release.
Model species, dextrans, were used to represent macromolecular drugs whereby
the effect of molecular weight could be studied. N-methyl pyrrolidone was added
to the polymer system as a biocompatible plasticiser to enhance molecular
mobility, and hence the transport of species. The effect of the addition of chitosan
was also studied, due to its bioadhesiveness and permeation enhancing ability.
A range of systems was investigated both in terms of water and species release.
The release of the agent was measured by a fluorometer, the leachable
components by HPLC and Confocal microscopy demonstrated the transport of
water and active species through the system. Immunological and viability studies
established whether the leachants or released components of the polymeric
systems had an inflammatory or irritant action on `in vitro' stratified epithelium.
The addition of N-methyl pyrrolidone, dextran and chitosan substantially
increased water uptake, thus affecting the release kinetics. Analysis of the
kinetics of water uptake showed Case I, combination of Case I and Case II, and
Case II kinetics, depending on the systems studied. Dextran release was largely
diffusion controlled, from which diffusion coefficients were calculated; the
amount released varied between the systems studied.
Authors
Hoque, ShahmaCollections
- Theses [4125]