Title:
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The controlled release of macromolecules from macroporous hydrophyllic polymer matrices
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This work has used novel polymer design and fabrication
technology to generate bead form polymer based systems, with
variable, yet controlled release properties, specifically for the
delivery of macromolecules, essentially peptides of therapeutic
interest. The work involved investigation of the potential
interaction between matrix ultrastructural morphology, in vitro
release kinetics, bioactivity and immunoreactivity of selected
macromolecules with limited hydrolytic stability, delivered from
controlled release vehicles.
The underlying principle involved photo-polymerisation of the
monomer, hydroxyethyl methacrylate, around frozen ice crystals,
leading to the production of a macroporous hydrophilic matrix.
Bead form matrices were fabricated in controllable size ranges in
the region of 100~ - 3mm in diameter. The initial stages of
the project involved the study of how variables, delivery speed
of the monomer and stirring speed of the non solvent, affected
the formation of macroporous bead form matrices. From this an
optimal bench system for bead production was developed. Careful
selection of monomer, solvents, crosslinking agent and
polymerisation conditions led to a variable but controllable
distribution of pore sizes (0.5 - 4~).
Release of surrogate macromolecules, bovine serum albumin and
FITC-linked dextrans, enabled factors relating to the size and
solubili ty of the macromolecule on the rate of release to be
studied. Incorporation of bioactive macromolecules allowed
retained bioactivity to be determined (glucose oxidase and
interleukin-2), whilst the release of insulin enabled
determination of both bioactivity (using rat epididymal fat pad)
and immunoreactivity (RIA).
The work carried out has led to the generation of macroporous
bead form matrices, fabricated from a tissue biocompatible
hydrogel, capable of the sustained, controlled release of
biologically active peptides, with potential use in the
pharmaceutical and agrochemical industries.
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