Gel Materials For The Delivery Of Bioactive Substances

University of California System: University of California, Berkeley
posted on 05/28/2009

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Protein therapeutics have great clinical potential and are currently being explored for the treatment of cancer, vaccine development and for manipulating the host response to implanted biomaterials. However, the effective utilization of protein therapeutics requires the development of materials that can deliver them to diseased tissues and cells. At present, the majority of protein delivery vehicles are based on hydrophobic polymers, such as poly(lactide-co-glycolide) (PLGA). PLGA based delivery vehicles, however are not very effective because of their poor water solubility that requires procedures that cause denaturation and inactivation of the proteins. Hydrogels and microgels have therefore been proposed as an alternative protein delivery vehicle because they can encapsulate the protein in a totally aqueous environment, under mild conditions. A key problem in the field of hydrogel research is the development of materials that can release their contents in response to pathological stimuli, allowing for the targeting of protein therapeutics to diseased tissues and cells. A particularly important pathological stimulus is mildly acidic pH. For example, tumors exist at acidic pHs between 6.4-6.8, and the phagolysosomes of phagocytic cells are at pHs between 4.5-5.0. The acidic nature of these compartments has stimulated a need for the development of hydrogels and microgels that can selectively release their contents under mildly acidic conditions.

This invention is directed towards novel microgels, microcapsules and related polymeric materials capable of delivering bioactive materials to cells for use as vaccines or therapeutic agents. The new materials have the common characteristic of being able to degrade under acid hydrolysis under conditions commonly found within the endosomal or lysosomal compartments of cells thereby releasing their payload within the cell. The materials can also be used for the delivery of therapeutics to the acidic regions of tumors and sites of inflammation.

This invention is directed towards novel microgels, microcapsules and related polymeric materials capable of delivering bioactive materials to cells for use as vaccines or therapeutic agents. The new materials have the common characteristic of being able to degrade under acid hydrolysis under conditions commonly found within the endosomal or lysosomal compartments of cells thereby releasing their payload within the cell. The materials can also be used for the delivery of therapeutics to the acidic regions of tumors and sites of inflammation.

The new materials have the common characteristic of being able to degrade under acid hydrolysis under conditions commonly found within the endosomal or lysosomal compartments of cells thereby releasing their payload within the cell.