Ethyl Corporation

Jan Crommen

Etienne Honore Schacht

Described are polyphosphazenes which may be represented by the general formula ##STR1## in which R is a hydroxy-substituted or protected hydroxy-substituted saturated aliphatic group, R' is a hydrocarbyl group, R' is a residue of an alpha amino acid, n is from about 50 to about 25,000, and x is a number averaging from 0.05 to 1.00 per repeating unit and y is a number averaging from 0.95 to 0.00 per repeating unit so that per repeating unit the sum of x and y is 1. Removal of the protecting group in the R moiety renders the polymers water soluble. The polymers have a controllable set of properties including degree of hydrolytic stability, permeability, hydrophilicity, and bioacceptability. They may be used in the production of hydrogels for drug release systems, plasma extenders, and biomedical implants.

Polyphosphazenes and their synthesis

A device for controlled release of one or more pharmacologically active substances within an animal which comprises (i) a body of a bioerodable solid state poly(amino acid ester) phosphazene polymer, and (ii) at least one pharmacologically active substance physically incorporated within said body. The device may comprise an implantable body in which the poly(amino acid ester)phosphazene polymer is a matrix within which such pharmacologically active substance is dispersed. Alternatively, the polymer may constitute a coating or container within which such pharmacologically active substance is physically encased--i.e., the polymer surrounds the active agent as in a capsule or in a microencapsulated form. Results of in vivo experiments using implants of poly[bis((ethyl glycino)phosphazene] containing 25% ethidium are described.

Bioerodable sustained release implants

The protecting group, Z, of protected alpha-amino acid esters of the formula

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Gent, Belgium

Jan Crommen