STW project on protein microencapsulation awarded to Wim Jiskoot

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The project “Controlled release of protein pharmaceuticals from biodegradable, hydrophilic microcapsules produced by supercritical fluid processing” has been granted to Prof. Wim Jiskoot (Division of Drug Delivery Technology) and co-applicant Prof. Geert-Jan Witkamp (section Process Equipment, TU Delft) by STW (Open Technology Programme). 

In this project, supercritical CO2 processing will be employed for producing a drug delivery system (DDS) based on stable protein-containing, carbohydrate based hydrophilic core microparticles coated with biodegradable, hydrophilic polymers. The proposed processes are mild for (intrinsically labile) proteins, non-toxic, environmentally benign, relatively inexpensive and scalable.

Therapeutic proteins are extremely valuable in the treatment of chronic and life-threatening diseases. However, they need to be regularly injected, often on a daily basis, or infused into patients, which is patient unfriendly and may compromise compliance. Moreover, infusions are expensive as they require hospitalisation and frequent injections imply fluctuating drug levels compromising safety and efficacy. The aim of this project is to develop a DDS platform for therapeutic proteins to prolong their therapeutic effect. Despite considerable research efforts to develop protein DDS, such systems are currently not available. The proposed DDS will stabilise the protein, be safe for the patient, and provide a sustained release profile that is tailorable to the needs of the specific protein therapy.

The DDS will be based on hydrophilic, fully biodegradable microcapsules intended for subcutaneous injection. The novelty of this proposal lies in the development of a novel process for the coating of dry protein-containing cores with a shell consisting of oppositely charged hydrophilic polymers. After contact with an aqueous medium (e.g., after injection) the protein will partly dissolve (until saturation) and dissolved protein will diffuse out of the capsules at a constant rate (zero-order release) for a period of up to 2 weeks. The release rate can be tailored by varying the characteristics of the polymer shell.