Covalent polymer-drug conjugates

Abstract

In this work, polymer-drugs conjugates used as drug delivery systems (DDS) are revised attending to their chemical conjugation. Namely, the classification of this type of DDS is based on the conjugation sites of the reactive groups (i.e., via end groups or pendant polymer groups). Advantages and limitations of these types of DDS are discussed through representative examples of polymer-drugs and polymer-proteins conjugates recently developed.

Figure 1

Ringsdorf model of synthetic polymer drugs.

Figure 2

Biodegradable bonds used to conjugate bioactive molecules to polymer backbones.

Figure 3

Typical end-group polymer-drug conjugate based on polyethylene glycol (PEG) modifications.

Figure 4

Chemical structure of SMANCS conjugates.

Figure 5

Chemical structure of HPMA copolymer-drug conjugate. X = peptide link, D = drug.

Figure 6

- Drug release at pH = 7.4 as (mg drug)/(g device) as a function of the time for all the copolymeric systems of 2-hydroxyethyl methacrylate, HEMA, and a methacrylamide that incorporates ibuprofen: N-{4-[2-(4-isobutylphenyl) propionyloxy] phenyl} methacrylamide, MAI. The weight compositions of the systems are 1 (○), 2.5 (□), 5 (Δ), 10 (), 20 () and 30 % ().