Enzyme-induced degradation of natural and artificial linear polyanions.

Synthetic and natural polymers are widely used for constructing drug delivery systems. Biocompatibility, water solubility and non-toxicity make polymers a convenient matrix for encapsulation, delivery and release of bioactive compounds. Coupling of a drug with a biodegraded polymer matrix is a promising way for a controlled drug delivery. Along this line, the degradation of the four polymers in the presence of two enzymes in aqueous solutions was investigated. The following polymers were used: natural polysaccharides, sodium alginate and sodium hyaluronate, artificial (modified) sodium carboxymethylcellulose and synthetic sodium polyacrylate (control); their degradation was caused by the addition of alginate lyase and hyaluronidase. The first enzyme only cleaved the specific alginate substrate and left three other intact. Contrastingly, the second enzyme degraded all three polysaccharides, including artificial carboxymethylcellulose, but did not degrade synthetic polyacrylate. The biodegradation of polymers was accompanied by decreasing the size of polymer particles in solution from 100 to 200 nm down to 20-30 nm; the latter are capable of removing from the body through the kidneys. The initial polysaccharides showed the negative surface charge in aqueous solution, which changed but retained negative after biodegradation. The initial and biodegraded polysaccharides demonstrated negligible cytotoxicity during long exposure period. The obtained results are valuable for the development of polymer carriers for drug encapsulation and delivery.