Biodegradable in Situ Microparticles for Sustained Protein Delivery: Stability of a Model Protein during Incorporation and Release from Biodegradable in Situ Forming Drug Delivery Systems

The objective of this work was to evaluate the suitability of in situ forming biodegradable microparticles for the controlled delivery of proteins. Particular goals were: a) to evaluate the flexibility of the release patterns of in situ implant and in situ microparticle formulations using hen egg white lysozyme as model protein; b) to characterize, if and how the integrity of the model protein is affected by formulation ingredients, the manufacturing process, storage of the ISM and the release from the formulations; c) to optimize protein delivery from in situ forming implant and microparticle systems, with regard to shape and completeness of the release; d) to find / validate reliable methods allowing to extract and thus to characterize the model protein in biodegradable in situ formulations.