Polyoxypropylene/polyoxyethylene copolmers with improved biological activity

DETAILED DESCRIPTION Although the prior art preparations of polyoxypropylene/polyoxyethylene block copolymers may have been suitable for industrial uses, it has been determined that the newly discovered uses for the copolymers as therapeutic agents require less polydisperse populations of molecules in the preparations.
The present invention comprises polyoxypropylene/polyoxyethylene copolymers that have a polydisperse value of less than 1.
05.
The novel copolymers can be prepared by removing disparate molecules from the prior art preparation or by preparing the copolymer according to the method that is contemplated as part of the present invention.
The method of preparation of the copolymers of the present invention is the purification of the polyoxypropylene block of the polyoxypropylene/polyoxyethylene copolymer before the polyoxyethylene blocks are added to the molecule.
In this way, the partially polymerized polyoxypropylene polymers are removed before the addition of polyoxyethylene polymers to the molecule.
This results in a block copolymer that is within the physical parameters which are contemplated as the present invention.
The present invention also comprises a polyoxypropylene/polyoxyethylene block copolymer which has the following formula: HO(C.
sub.
2 H.
sub.
4 O).
sub.
b (C.
sub.
3 H.
sub.
6 O).
sub.
a (C.
sub.
2 H.
sub.
4 O).
sub.
b H wherein the molecular weight represented by the polyoxypropylene portion of the copolymer is between approximately 900 and 15000 daltons with a more preferred molecular weight of between 1,200 and 6500 daltons and the molecular weight represented by the polyoxyethylene portion of the copolymer constitutes between approximately 5% and 95% of the copolymer with a more preferred range of between approximately 10% and 90% of the copolymer and the polydispersity value is less than approximately 1.
07.
The present invention also comprises a polyoxypropylene/polyoxyethylene block copolymer which has the following formula: HO(C.
sub.
2 H.
sub.
4 O).
sub.
b (C.
sub.
3 H.
sub.
6 O)