Varying polymer architecture to deliver drugs

Abstract

Variable architecture polymers are of considerable interest for the delivery of therapeutic biopolymers, such as DNA and proteins, to their site of action. Polymers that can respond with a change in conformation to biologically relevant stimuli, such as temperature and pH, are being carefully designed to take advantage of the change in environmental conditions the polymer-drug conjugate encounters upon progression from larger-scale systems in the body to subcellular compartments. Viruses respond to changes in the cellular environment to gain access to their desired region of cells, and much can be learned from the mechanisms they employ in this effort. However, despite the efficiency of therapeutic biopolymers, undesirable immune and inflammatory responses may result from their repeated administration, so synthetic polymers are an attractive alternative. This mini-review examines a range of recently developed variable architecture polymers, mainly focusing on polymers responsive to temperature and pH, covering both synthetic copolymers and derivatives of naturally occurring polymers for advanced drug delivery applications. The polymers discussed in the article have some of the properties that are most important for polymer drug delivery vehicles to be effective, such as biodegradability, specificity, and biocompatibility.

Potential Oral Delivery of 7-Ethyl-10-Hydroxy-Camptothecin (SN-38) using Poly(amidoamine) Dendrimers

“…There is a growing interest in the use of polymers for delivery of therapeutic compounds lacking suitable pharmacokinetic parameters (17,18) and PAMAM dendrimers are emerging as promising candidates for oral drug delivery (9,11,13). These polymers are transported across epithelial cell monolayers via trans-and para-cellular permeation pathways (19).…”

Binding and release studies of a cationic drug from a star-shaped four-arm poly(ethylene oxide)-b-poly(methacrylic acid)

“…In addition, PEO improves the biocompatibility of foreign materials due to its high solubility and mobility in aqueous solution, unique solution properties, minimal interfacial free energy with water and large excluded volume 25–27. In contrast to the widely reported studies on linear PEO systems, the three‐dimensional branched structures possess unique physicochemical properties that could potentially be useful in some applications 28. The star shape multi‐arm PEOs when combined with other responsive polymeric segments possess three‐dimensional architecture that can self‐assemble and associate to form nanostructures in the presence of drug and gene 29.…”

Challenges for Natural Monomers and Polymers: Novel Design Strategies and Engineering to Develop Advanced Polymers

“…Improved methods of block co-polymer synthesis, such as emulsion polymerization using amphiphilic block co-polymers as emulsifiers and controlled mineralization using block or comb co-polymers as additives in crystallization from aqueous solution, so-called mineralization processes akin to bio-mineralization, have a strong influence on properties. Synthetic polymers are now being designed which have multiple H-bond donors, acceptors and hydrophobic domains with a view to binding selectively, for example, to cellsurface saccharides with high specificity [87][88][89][90][91][92][93].…”