Recent years, biomolecules such as proteins, peptides, hormones and enzymes have shown a substantial increase as drug candidates. It is mainly attributed to their high specificity, rapid onset of action and requirement for relatively small doses compared to conventional synthetic molecules. Unfortunately, most biomolecules are characterized by short circulating lives, low stability due to proteolytic and enzymatic degradation in vivo and rapid clearance from the body via glomerular filtration. To overcome this, during drug formulation the biomolecules can be protected through covalent binding with other macromolecules. Polymers play a versatile role in such conventional drug formulations; they serve as binding agents in capsules, film coating agents in tablets and viscosity enhancers in emulsions and suspensions. Some of the polymers are conjugated with bioactive drug molecules include cellulose derivatives, poly (N-vinyl pyrrolidone) and poly (ethylene glycol) (PEG). The resulting polymer bioconjugates are characterised by improved properties such as reduced immunogenicity, decreased antibody recognition, increased in vivo residence time, increased drug targeting specificity and bioavailability, and improved pharmacokinetics. At Creative BioMart, besides the widely used PEG, alternative natural and synthetic polymers are also being examined, such as polyoxazolines, poly(N-(2-hydroxypropyl) methacrylamide) (PHPMA), poly(oligoethylene glycol methyl ether methacrylate) (POEGMA), and hydroxyethyl starch.

Another widely used polymer candidate for drug conjugation is dentrimer, which is composed of several extremely branched monomers that emerge radially from the central core. Dentrimers are used as a multifunctional drug delivery system due to the fact that the surface, internal cavity and dendrimer core could be modified enable them to simultaneously conjugate with several molecules such as imaging contrast agents, ligands or therapeutic drugs. This concept of polymer-drug conjugation has been extended to small, high-value prodrugs, lead to a new era of drug delivery systems.

Our Professional PEGylation service: https://www.creativebiomart.net/pegylation-services.htm

Simultaneous delivery of drugs by conjugation with polymer branches. Reprinted from C Lee, J.H, et al. Journal of Drug Delivery 2012.