Abstract: Methods for preparing a PEG composition by co-precipitation of two or more components to produce a substantially homogenous powder. According to some embodiments, the two or more components are at least and partially soluble in a solvent, and at least one component is a functionalized PEG. Contacting the at least two component with the solvent at least partially dissolves the components which are then co-precipitated. The resulting product is substantially homogenous, unlike product made by other methods. The PEG composition may be co-precipitated with additional compounds, such as a colorant like indocyanine green.

Abstract: Methods for preparing a PEG composition by co-precipitation of two or more components to produce a substantially homogenous powder. According to some embodiments, the two or more components are at least and partially soluble in a solvent, and at least one component is a functionalized PEG. Contacting the at least two component with the solvent at least partially dissolves the components which are then co-precipitated. The resulting product is substantially homogenous, unlike product made by other methods. The PEG composition may be co-precipitated with additional compounds, such as a colorant like indocyanine green.

Abstract: Methods for forming maleimide functionalized polymers are provided. In one such embodiment, a maleimide functionalized polymer is prepared in a method that includes a step of carrying out a reverse Diels-Alder reaction. Intermediates useful in the methods, as well as methods for preparing the intermediates, are also provided. Also provided are polymeric reagents, methods of using polymeric reagents, compounds and conjugates.