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US 6,319,984 B1Granted
Biodegradable and thermosensitive polyphosphazenes and their preparation method
AssigneeKorea Institute of Science and Technology
InventorsSoo-Chang Song, Youn Soo Sohn, Bae Hoon Lee, Sang Beom Lee
Life of this patent
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Abstract
The present invention relates to novel biodegradable polyphosphazenes represented by Formula 1 and a preparation method thereof. Polyphosphazenes of the present invention not only have thermosensitivity and biodegradability simultaneously, but also their phase transition temperature and degradation rate can be controlled.
Claims17
Polyphosphazenes represented by Formula 1:
- wherein X is O or NH, NHR is a depsipeptide selected from the group consisting of NHCH2COOCH2COOC2H5 or NHCH2COOCH(CH3)COOC2H5, NHR′ is an amino acid ethylester selected from the group consisting of NHCH(CH2CH2COOC2H5)COOC2H5, NHCH(C7H7)COOC2H5, NHCH(CH(CH3)2)COOC2H5, or NHCH(CH2CH(CH3)2)COOC2H5, NHR″ is NHCH2COOC2H5 or NHCH(CH3)COOC2H5, and a, b, c, d, e and f are mole fractions of each copolymer that have values between 0˜1.0 with a relationship a+b+c+d+e+f=1.0 and n is a degree of polymerization of the polyphosphazene and is between 100˜1000.
A process of preparing polyphosphazenes of Formula 1 comprising the steps of:
- a) reacting polydichlorophosphazene of Formula 3 with alkali metal salt of methoxy-poly(ethylene glycol) of Formula 4 or α-amino-ω-methoxy-poly(ethylene glycol) of Formula 5 in a mole ratio of 1:0.3˜1.5;
- b) reacting the product of step a) with depsipeptide of Formula 6 and glutamic acid ethyl ester, phenylalanine ethyl ester, valine ethyl ester, or leucine ethyl ester of Formula 7 in a mole ratio of 1:0.1˜2 in an organic solvent;
- and
- c) reacting glycine ethyl ester or alanine ethyl ester of Formula 8 with an unsubstituted chlorine
- wherein X is O or NH NHR is a depsipeptide selected from the group consisting of NHCH2COOCH2COOC2H5 and NHCH2COOCH(CH3)COOC2H5, NHR′ is an amino acid ethyl ester selected from the group consisting of NHCH(CH2CH2COOC2H5)COOC2H5, NHCH(C7H7)COOC2H5, NHCH(CH(CH3)2)COOC2H5, or NHCH(CH2CH(CH3)2)COOC2H5, NHR″ is NHCH2COOC2H5 or NHCH(CH3)COOC2H5, and a, b, c, d, e and f are mole fractions of each copolymer that have values between 0˜1.0 with a relationship a+b+c+d+e+f=1.0 and n is a degree of polymerization of the polyphosphazene and is between 100˜1000.
2 more elements
Dependencies are inferred from the claim text.