Method for preparing branched functionalized polymers using branched polyol cores
View Patent ↗A method of preparing a multiarm polymer includes reacting a branched polyol with one or more functionalizing reagents to effect substitution of an ionizable functional group or a protected ionizable functional group, Y, to form a mixture comprising (i) unsubstituted branched polyol containing no Y groups; (ii) a monosubstituted polyol comprising one Y group, and (iii) a multisubstituted polyol (e.g., a disubstituted polyol comprising two Y groups); followed by purifying the mixture to separate the monosubstituted polyol from other species Thereafter, a water-soluble and non-peptidic polymer segment is attached to the monosubstituted branched polyol at the site of at least one of the hydroxyl groups. The invention also provides purified monosubstituted branched polyols and multiarm polymers prepared by the method and polyol precursors for use in the method.
1. A chromatographically purified branched polyol having the structure Y—R(—OH) p , wherein R is a branched hydrocarbon, Y is an ionizable functional group selected from the group consisting of amine and carboxylic acid, and p is at least 2, and further wherein (i) the branched polyol has a single ionizable functional group, optionally in protected form, (ii) the polyol has a purity of at least about 83%, and (iii) the R group includes a poly(alkylene glycol) chain of 1 to about 25 monomer subunits attached to each terminal hydroxyl group.
2. The branched polyol of claim 1 , wherein the polyol has a purity of at least about 91%.
3. The branched polyol of claim 2 , wherein the polyol has a purity of at least about 97%.
4. The branched polyol of claim 3 , wherein the polyol has a purity of about 100%.
5. The branched polyol of claim 1 , wherein p is 3 to about 25.
6. The branched polyol of claim 1 , wherein p is 3 to about 10.