Heterotelechelic block copolymers and process for producing the

Details Heterotelechelic block copolymers and process for producing the Heterotelechelic block copolymers and process for producing the

1997-12-18

1999-07-20

Nutter, Nathan M.

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

525922, 424450, C08G 6308, C08G 6366, C08G 6526, C08G 6532

Patent

active

059257202

DESCRIPTION:

BRIEF SUMMARY
This application is filed under 35 USC 371 as PCT/JP96/01057, filed Apr. 18, 1996 under 37 USC 371.


FIELD OF THE INVENTION

The present invention relates to a heterotelechelic block copolymer which has different functional groups on its both ends, a method for the production thereof and its application to high-molecular micelle. More detailedly, this invention discloses a polymer which has different functional groups on its both ends while having, in its main chain, polyethylene oxide as a hydrophilic segment and polyester as a hydrophobic segment.
In this invention, the term "polymer" includes oligomer.


PRIOR ARTS

A high-molecular micelle or nanosphere composed of a hydrophilic/hydrophobic type block copolymer wherein a hydrophilic polymer like polyethylene oxide is combined with a hydrophobic polymer at the molecular level is now attracting attention as a carrier for drug delivery or the like. Said high-molecular micelle and nanosphere have been prepared from a hydrophilic/hydrophobic type block copolymer wherein a hydrophilic polymer is combined with a hydrophobic polymer at the molecular level.
In conventional processes to produce a hydrophilic/hydrophobic type block copolymer, however, there is a limitation on the species of terminal functional groups introduced, and there have only been proposed block copolymers whose functional groups are restricted to methoxy and hydroxyl groups. If one succeeded in introducing optional functional groups onto the micelle surface at an optional proportion, it would become possible to provide a functional high-molecular micelle which could useful for drug delivery to certain organs.
The object of this invention is to provide a block copolymer, which has different functional groups on its both ends, as a polyfunctional polymer which is capable of forming a high-molecular micelle.


DISCLOSURE OF INVENTION

The inventors of this invention have found out that there can easily be produced a block copolymer which has a protected or non-protected aldehyde group on one and of molecule and various functional groups on the other end, when an alkylene derivative having a certain kind of aldehyde group and a hydroxyl group is utilized as a living polymerization initiator and when ethylene oxide and lactide or lactone are polymerized as monomers.
They have also confirmed that a block copolymer obtained in this manner forms a high-molecular micelle which is quite stable in an aqueous solvent.
This invention provides a heterotelechelic block copolymer which has different functional groups on both ends of molecule and which is represented by formula (I) below: ##STR2## wherein R.sup.1 and R.sup.2 independently denote C.sub.1-10 alkoxy, aryloxy or aryl-C.sub.1-3 alkyloxy, or R.sup.1 and R.sup.2, combined with each other, denote ethylenedioxy (--O--CH(R')--CH.sub.2 --O--: wherein R' denotes hydrogen atom or C.sub.1-6 alkyl) which may be substituted with C.sub.1-6 alkyl, or, combined with each other, denote oxy (.dbd.O), ##STR3## or .paren open-st.CH.sub.2 .paren close-st..sub.r wherein R.sup.3 and R.sup.4 independently denote hydrogen atom, C.sub.1-10 alkyl, aryl or aryl-C.sub.1-3 alkyl, and r denotes an integer of 2-5, acryloyl, methacryloyl, cinnamoyl, p-toluenesulfonyl, 2-mercaptopropionyl or 2-aminopropionyl, or allyl or vinylbenzyl, while, when q is an integer of 1-20, denoting C.sub.1-6 alkoxycarbonyl, carboxyl, mercapto or amino.
As another aspect, this invention provides a process to produce the block copolymer of the above formula (I) which process comprises the following steps:
A polymerization initiator represented by the following formula (II) ##STR4## wherin R.sup.1-1 and R.sup.2-1 independently denote C.sub.1-10 alkoxy, or, R.sup.1-1 and R.sup.2-1, combined with each other, denote ethylenedioxy which may be substituted with C.sub.1-6 alkyl, p denotes an integer of 1-5 and M denotes alkali metal following formula (II) may be produced: ##STR5## wherein R.sup.1-1, R.sup.2-1, p and M are as defined in formula (II), and m denotes an integer of 2-10,000.
The compound of

REFERENCES:
patent: 5153297 (1992-10-01), Munzmay et al.
patent: 5410016 (1995-04-01), Hubbell et al.
English Abstract--International Publication No. WO 93/00101
International Search Report of PCT/JP96/01057

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