Effect of cationized gelatins on the paracellular transport of drugs through caco-2 cell monolayers.

Cationized gelatins, candidate absorption enhancers, were prepared by addition of ethylenediamine or spermine to gelatin and the effects of the resulting ethylenediaminated gelatin (EG) and sperminated gelatin (SG) on the paracellular transport of 5(6)-carboxyfluorescein (CF), FITC-dextran-4 (FD4), and insulin through caco-2 cell monolayers were examined. The Renkin function was used for characterization of the paracellular pathway and changes in the pore radius (R) and pore occupancy/length ratio (epsilon/L) calculated from the apparent permeability coefficients (P(app)) of CF and FD4 are discussed. Ethylenediaminetetraacetic acid (EDTA) increased the R of the caco-2 cell monolayer and the P(app) of all compounds examined was markedly increased by the addition of EDTA.

Effect of aminated gelatin on the nasal absorption of insulin in rats.

Absorption enhancers, which increase the permeability of drugs through epithelial membranes without damaging them, are especially useful for intranasal administration of peptide drugs. In this study, aminated gelatins, candidate enhancers, having different numbers of amino groups were prepared from gelatin (H-gelatin, isoelectric point = 9.0, MW 100 kDa) and a partial gelatin hydrolysate (L-gelatin, isoelectric point = 8.