Polymer systems are being developed for in-vivo applications, including drug delivery vehicles for controlled release of drugs when implanted in a subject's body. These systems are particularly useful for therapeutic biomolecules such as proteins or peptides which tend to be very sensitive to degradation within the body. The synthesis of thermogelling polymers has attracted much attention due to their suitability for applications such as drug delivery and tissue engineering. Low critical gelation concentration ("CGC") is preferred as lower concentrations of polymer can be used to create a gel, resulting in smaller amounts of polymer being implanted in a subject. Presently, attempts have been made to lower the CGCs of a thermogelling copolymer. However, these polymers are non-biodegradable and clearance from body could be difficult. There is thus a need for a biodegradable, thermogelling polymer that exhibits a lower CGC compared to existing polymers.
Our invention comprises of novel polymers consisting of blocks of poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG) and poly(hydroxybutyrate) (PHB). These multiblock polymers are biocompatible, biodegradable, have thermogelling characteristics and have relatively low critical gelling concentrations, making them suitable for various in vivo applications. PEG provides hydrophilic blocks that can absorb and retain large quantities of water. PPG blocks are highly thermosensitvie and provide a balanced hydrophobicity and hydrophilicity at different temperatures, facilating the formation of a thermosensitive hydrogel. PHB is a natural biopolyester that degrades to give 3-hydroxybutyric acid, which is a trace component in the human blood. Incorporating these blocks with PEG and PPG allows for the formation of physical crosslinking in the hydrogel, increasing its resilience. Also, the PHB blocks provide biodegradable segments facilitating the degradation of the polymer into smaller fragments and subsequent removal of the polymer from the body.
Licensing, Co-Development, Start Up Company.