Thus, in order to direct the biodistribution of CAL101/nucleic acid nanoparticles such that tumor uptake is maximized (and the potential for off-target deposition and toxicities are minimized), efforts to incorporate a neutral polymer, PEG, to stabilize these nanoparticles

were undertaken. While PEGylation of cationic polymer-based nanoparticles to extend circulation times and prevent aggregation was widely performed, it typically required covalent attachment of PEG at the same polymer functional Inhibitors,research,lifescience,medical sites required for nucleic acid binding. This tradeoff is undesirable, and it was overcome in this case due to exploitation of the β-CD moiety within CAL101 (Figure 7). Forming strong noncovalent inclusion complexes with β-CD (association constant of ~ 104-105M−1), adamantane (AD) was conjugated to one terminus of a linear PEG (AD-PEG) and added to CAL101 either before (pre-PEGylation) Inhibitors,research,lifescience,medical or after (post-PEGylation) CAL101 had been combined with the nucleic acid of interest. In this manner, simple physical Inhibitors,research,lifescience,medical mixing of these components was sufficient to achieve sufficient interaction and incorporation

of AD-PEG into the nanoparticles. A minimum PEG length of 5kDa was shown to be required to prevent salt-induced aggregation of these nanoparticles [21], and thermodynamic analysis suggests that length-dependent interactions among PEG chains on the surface of nanoparticles

contribute significantly to the effective stabilization [36]. This AD-PEG5000 conjugate was the focus of future development work for this Inhibitors,research,lifescience,medical Enzalutamide price RONDEL delivery platform as well as clinical translation of the CALAA-01 therapeutic candidate. Figure 7 Formation of inclusion complexes between adamantane (AD) Inhibitors,research,lifescience,medical and β-cyclodextrin allows straightforward, noncovalent incorporation of stabilizing (via PEG-AD conjugates) and/or targeting (via ligand-PEG-AD conjugates) components to a polymer-nucleic … Having included CAL101 as a condensing agent to induce nanoparticle formation and AD-PEG as a stabilizing agent to render these nanoparticles suitable for in vivo application, a third component was investigated which would facilitate cellular internalization of nanoparticles. GSK-3 Typical candidates for such an agent in nanoparticle formulations are ligands (in the form of peptides, proteins/antibodies, aptamers, or small molecules) whose cognate receptor is expressed on the surface of target cells either exclusively or to a much greater extent than on other (nontarget) cells. For application of these nanoparticles to cancer, the transferrin receptor (TfR) was selected [22] as a target owing to its significant overexpression on a variety of cancer cell types [37]; indeed, TfR is a well-studied surface protein for targeting of cancer therapeutics [38, 39].