DIFFUSION CHARACTERISTICS OF FIBRIN FILMS

Fibrin films prepared by enzymatic conversion of fibrinogen using thrombin were evaluated as a biodegradable and biocompatible carrier for drug delivery. Permeabilities, partition coefficients and diffusion coefficients were employed to characterize the diffusion of various solutes through fibrin film. For a series of alkyl parabens, permeabilities decreased and partition coefficients into the films increased with increasing chain length of the alkyl group. On the other hand, there was no significant alteration of diffusion coefficients for propyl paraben permeating through fibrin films treated with glutaraldehyde for different intervals. However, permeabilities of various macromolecules decreased as the time interval of crosslinking increased. A linear correlation between the logarithm of permeability and the square of macromolecular radius was observed. Partition coefficients increased for all macromolecules examined with increasing extent of crosslinking as a result of introducing hydrophobic glutaraldehyde into fibrin film. Diffusion of macromolecules through free water regions within the films is a possible mechanism.