Polyglutamates are well known to be highly biocompatible, biodegradable and multifunctional polymers, which have been already used as building blocks in
polymer drug conjugates and
polymeric micelles. Those systems have been applied to various medical applications
ranging from therapy to
molecular imaging. Furthermore a
polyglutamic acid (PGA)
paclitaxel conjugate has already entered clinical studies (Opaxio™ PGA-PTX conjugate currently in phase III of Clinical trials).In this context, a synthetic pathway to a plethora functional polyglutamates (homopolymers, block-co-polymers, triblocks) with well-defined structure, adjustable molecular weight (Mw) and low
dispersity (D=Mw / Mn<1.2) applying the
ring opening polymerization (ROP) of N-carboxyanhydrides (NCA) has been developed. Additionally, the acid moieties of the polyglutamates can be activated with 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium (DMTMM) and various functionalities can be easily introduced by “post-
polymerization modification” yielding a set orthogonal reactive attachment sides. The reactive moieties, such as azides, maleimides, thiols, alkynes (linear or cyclic) offer the opportunity of specific conjugation of the drugs, targeting moieties or markers. Besides introducing reactive groups the functionalization strategy was also used for
PEGylation of PGA reducing charge induced interactions and therefore pharmacological properties, such as
blood circulation time may be adjusted.In summary, a tool kit of various polyglutamates has been developed enabling the synthesis of a variety of
polymer drug conjugates or
polymer based imaging agents. The functional polymeric precursors developed will allow us to functionalize and therefore adjust the polymer properties to a desired application.