Reversibly Masked Polymers

Abstract

The present invention is directed to reversibly inactivation of membrane active polymers useful for cellular delivery of compounds. Described are polyconjugates systems that incorporate targeting, anti-opsonization, anti-aggregation, and transfection activities into small biocompatible in vivo delivery conjugates. The use of multiple reversible linkages connecting component parts provides for physiologically responsive activity modulation.

Description

BACKGROUND OF THE INVENTION[0001]The delivery of polynucleotide and other membrane impermeable compounds into living cells is highly restricted by the complex membrane systems of the cell. Drugs used in antisense and gene therapies are relatively large hydrophilic polymers and are frequently highly negatively charged as well. Both of these physical characteristics preclude their direct diffusion across the cell membrane. For this reason, the major barrier to polynucleotide delivery is the delivery of the polynucleotide to the cellular interior. Numerous transfection reagents have been developed to deliver polynucleotides to cells in vitro. However, in vivo delivery of polynucleotides is complicated by toxicity, serum interactions, and poor targeting of transfection reagents that are effective in vitro. Transfection reagents that work well in vitro, cationic polymers and lipids, typically destabilize cell membranes and form large particles. The cationic charge of transfection reagent...

AI Technical Summary

Benefits of technology

[0013]In a preferred embodiment, a polynucleotide is attached to the polymer in the presence of an excess of polymer. The excess polymer may aid in formulation of the polynucleotide-polymer conjugate. The excess polymer may reduce aggregation of the conjugate during formulation of the conjugate. The polynucleotide-polymer conjugate may be separated from the excess polymer prior to administration of the conjugate to the cell or organism. Alternatively, the polynucleotide-polymer conjugate may be co-administered with the excess polymer to the cell or organism. The excess polymer may be the same as the polymer or it may be different, a helper or boost polymer.

[0014]In a preferred embodiment, the described membrane active amph

Problems solved by technology

Drugs used in antisense and gene therapies are relatively large hydrophilic polymers and are frequently highly negatively charged as well.

However, in vivo delivery of polynucleotides is complicated by toxicity, serum interactions, and poor targeting of transfection reagents that are effective in vitro.

Transfection reagents that work well in vitro, cationic polymers and lipids, typically destabilize cell membranes and form large particles.

These properties render transfection reagents ineffective or toxic in vivo.

Cationic charge results in interaction with serum components, which causes destabilization of the polynucleotide-transfection reagent interaction and poor bioavailability and targeting.

Cationic charge may also lead to in vivo toxicity.

Membrane activity of transfection reagent, which can be effective in vitro, often leads to toxicity in vivo.

Cationic charge on in vivo transfection complexes leads to adverse serum interactions and therefore poor bioavailability.

Further, these electrostatic complexes tend to aggregate or fall apart when exposed to physiological salt concentrations or serum components.

Finally, transfection complexes that are effective in vitro are often toxic in vivo.

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