Therapeutic peptides (TPs) are one of the fastest growing classes of pharmaceuticals with clinical applications in cancer therapy, hormonal or immune disorders, and infectious or metabolic diseases. The number of approved TPs is rapidly increasing, however, to date the vast majority of TPs (> 90%) rely on administration via injections, e.g. insulin, whereof half even need to be administered intravenously and are therefore limited to the clinical environment. This considerably affects patient wellbeing and compliance, as well as treatment costs and ease of distribution. Oral delivery of TPs provides an alternative administration route that is straightforward, cheap, and highly accepted by patients and clinicians. However, the oral administration of TPs is limited by I) the proteolytic gastric and intestinal environments which are detrimental for TPs and II) limited permeation of TPs across the intestinal epithelium. Double water-in-oil-in-water emulsions are of interest as potential oral delivery systems as they allow the encapsulation and co-delivery of hydrophilic and hydrophobic compounds such as TPs and permeation enhancers, respectively. Particularly emulsions stabilized by solid particles, known as Pickering emulsions, have proven promising for the formation of gastric stable emulsions. The goal of OraPickering was to establish Pickering double emulsions as novel oral delivery systems for co-delivery of hydrophilic TPs and hydrophobic permeation enhancers, towards more safe, cheap, and compliant administration of TPs like insulin. The main objectives of OraPickering were 1) to find stable formulations for Pickering double emulsions, 2) test the stability of emulsions and encapsulated TPs under gastric conditions, and 3) confirm their efficacy for intestinal delivery in in vitro cell models.
