Glyceryl polyphosphazenes: synthesis, properties, and hydrolysis

Electrospun Polyphosphazene Nanofibers for In Vitro Osteoblast Culture

“…In fact, in the first week the weight loss of the dried sample was negligible; after this period the polymer matrix displayed a nearly constant degradation kinetic, losing approximately 20% of its mass in 100 days. The mass loss of the dried sample can be ascribed to the two previous degradation processes and to hydrolysis of the skeleton of the polyphosphazene chain by the deprotected carboxylic acid function of the substituent units or attack by H + ions on skeletal nitrogen atoms according to the mechanism of hydrolytic breakdown for amino acid ester polyphosphazene (Allcock and Kwon, 1988). This degradation reaction of phosphorus-nitrogen chains is slower that the two previous mechanisms and is the most important process for the weight loss of the polymer because it leads to a molecular-weight decrease (Carampin et al, 2007;Ruiz et al, 1993.…”

“…The polymers degrade in aqueous medium to nontoxic products, including ammonia, phosphate, amino acids, and the corresponding alcohol. Polyphosphazenes with ethyl or benzyl glycolic ester and lactic ester as substituents were also found to undergo hydrolytic degradation, yielding, in this case, phosphate and the corresponding acid and alcohol (Allcock and Kwon, 1988). The amino acid ester polyphosphazenes are perhaps the most extensively studied biodegradable polyphosphazenes, particularly as controlled drug delivery systems.…”

Phosphor oder Schwefel in der Hauptkette enthaltende Polymere und ihre Anwendung als hochtemperatur‐ und medienbeständige Beschichtungsstoffe

“…Die Zahl der Patente nimmt standig zu, und es erscheinen jahrlich Patentubersichten [12]. Ubersichten uber reale und potentielle Anwendungen von Poly(organophosphazenen) in der Technik, der Landwirtschaft und der Textilindustrie sowie als Tragerstoffe fur Pharmaka, Enzyme, Farbstoffe, Katalysatoren u. a. werden in [6,[49][50][51] Wegen der geringen Entflammbarkeit, Rauchbildung und Bildung toxischer Gase der halogenfreien Phenoxypolyphosphazene ist ihre Anwendung als Schaumgummipolster, Isolation und zum Beschichten elektrischer Kabel vorgesehen.…”

Novel biodegradable polyphosphazenes containing glycine ethyl ester and benzyl ester of amino acethydroxamic acid as cosubstituents

“…Although the controllable degradation rates of polyphosphazenes can be achieved, almost all of them degrade very slowly under physiological conditions. [3][4][5][6] This drawback may limit their applications in certain drug-delivery systems, such as a pulsatile drug-delivery system in which fast controlled drug release is required. To overcome this problem, we recently prepared novel biodegradable polyphosphazenes containing glycine ethyl ester and benzyl ester of amino acethydroxamic acid as cosubstituents (PGBP), which can be hydrolyzed at a higher rate under physiological conditions, but be relatively stable at low pH.…”