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Controlled drug delivery remains a research focus for public health to enhance patient compliance, drug efficiency and reduce the side effects of drugs. Pectin, an edible plant polysaccharide, has been shown to be useful for the construction of drug delivery systems for specific drug delivery. Several pectin derived formulations have been developed in our laboratory and tested in vitro, ex vivo, and in vivo for the ability to deliver bioactive substances for therapeutic purposes in the context of interactions with living tissues. Pectin derivatives carrying primary amine groups were more mucoadhesive and have shown potential in nasal drug delivery and other mucosal drug delivery. Pectin derivatives with highly esterified galacturonic acid residues are more hydrophobic and able to sustain the release of incorporated fragrances for a prolonged duration. Less esterified pectin derivatives are able to penetrate deeper into the skin and may be useful in aromatherapy formulations. Pectin, in combination with zein, a corn protein, forms hydrogel beads. The bound zein restricts bead swelling and retains the porosity of the beads; the pectin networks shield the zein from protease attack. The complex beads are ideal vehicles for colon-specific drug delivery. Studies presented in this paper indicate the flexibility and possibility to tailor pectin macromolecules into a variety of drug delivery systems to meet different clinical requirements.

Exopolysaccharides (EPS) of the soybean pathogen Pseudomonas syringae pv. glycinea were isolated from culture ifitrates and infected soybean leaves. Levan (a polyfructan with a C-2 --C-6 backbone and C-2 -+ C-1 branching) or acetylated alginate (a linear polyuronide of C-1-+ C-4-linked mannuronic and guluronic acids) was isolated from culture filtrates when bacterial strains were grown in a semisynthetic medium containing sucrose or glucose, respectively, as the primary carbon source. Acetylated alginate was the only EPS isolated from soybean [Glycine max (L.) Merr.] leaves inoculated with compatible (disease-inducing) strains of P. syringae pv. glycinea. The acetyl content of the P. syringae pv. glycinea alginates varied from 3 to 14%, and the amount of guluronic acid varied from less than 1 to 20%. The P. syringae pv. glycinea alginates from in vitro batch cultures were of lower molecular weight and polydispersity thakm those from in planta cultures, and both were of lower molecular weights than alginates produced by Pseudomonas aeruginosa.

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