Abstract: A composition and method for inducing a protective immune response to HIV-1 in an individual, of (a) a replication incompetent HIV-1, HIV-1 pseudovirus, HIV-1 VLP or oligomeric gp120; and (b) a water soluble polyphosphazene polyelectrolyte, wherein (a) and (b) are present in an amount effective to induce a protective immune response against HIV-1.

Abstract: A method for producing a polyorganophosphazene, such as, for example, poly?di(carboxylatophenoxy)phosphazenel!, from polydichlorophosphazene. The polydichlorophosphazene is reacted with at least one nucleophilic reagent at a defined molar ratio of the at least one nucleophilic reagent to the polydichlorophosphazene. Such process results in the production of a polyorganophosphazene having a molecular weight within a desired range.

Abstract: A method for purification of a polyphosphazene polyacid or acid salt thereof in which a polyphosphazene polyacid or acid salt thereof is dissolved in a concentrated aqueous solution of a salt of monovalent ions. The resulting aqueous solution of the polyphosphazene polyacid or acid salt thereof and the at least one salt of monovalent ions then is diluted to reduce the concentration of the at least one salt of monovalent ions, whereby the polyphosphazene polyacid or acid salt thereof is precipitated. The precipitated polyphosphazene polyacid or acid salt thereof then is recovered.

Abstract: A process for recovering a polyphosphazene polyacid or acid salt obtained by hydrolyzing a polyphosphazene having at least one ester moiety present in at least one substituent group. The polyphosphazene having at least one ester moiety present in at least one substituent group is hydrolyzed with a base in an organic solvent in the presence of water. The water is present in an amount effective to induce the agglomeration of particles of the synthesized polyphosphazene polyacid or acid salt, which enhances the separation of the polyphosphazene polyacid or acid salt from a polymer-free liquid organic phase. The polymer-free liquid organic phase then is separated from the polyphosphazene acid or acid salt, whereby the polyphosphazene acid or acid salt is recovered.

Abstract: A method is provided for preparing polyphosphazene microspheres wherein the polyphosphazene microspheres are produced by coacervation. A solution containing a polyphosphazene is admixed with a solution containing a salt of a monovalent ion such as a salt of a Group I element (for example, NaCl) to form a dispersion containing polyphosphazene coacervate microdroplets. The dispersion then is admixed with a solution containing a salt of a multivalent ion, such as a salt of a Group II element (for example, CaCl.sub.2) to form a suspension of polyphosphazene microspheres. The polyphosphazene microspheres then are recovered from the suspension. Such method enables one to obtain high yields of microspheres having a controlled size distribution. Polyphosphazene microspheres containing biological material can be produced by providing a biological material in the polyphosphazene solution that is mixed with the solution containing a salt of a monovalent ion.

Abstract: A process for producing a polyorganophosphazene from a polyhalophosphazene. The polyhalophosphazene is reacted with a metal salt of an alkyl ester of hydroxybenzoic acid wherein the metal salt of the alkyl ester of hydroxybenzoic acid is contained in a homogeneous melt solution. The reaction of the polyhalophosphazene with the metal salt of an alkyl ester of hydroxybenzoic acid produces a macromolecular substituted polymer, which is reacted with a base to hydrolyze the polymer and produce the desired polyorganophosphazene product.

Abstract: A solution which comprises a polyphosphazene solute, such as a polyhalophosphazene solute, and a stabilizing solvent such as diglyme. Such solution enables the polyphosphazene to remain stable for extended periods of time so that such polyhalophosphazenes may be employed for further modification or use.