Peptide therapeutics hold great value in the pharmaceutical portfolio as drugs that can treat a variety of acute and chronic hormone-based diseases with minimal side effects.  Having high activity and specificity at their therapeutic targets, peptides are usually larger and more flexible than conventional small drug molecules which allows for better interaction with biological targets that have shallow and/or extended binding pockets that are not usually accessible to small molecular drugs.

Medications often seek oral delivery as their choice route of administration particularly when multiple doses are required and/or the disease is chronic and requires long term or even lifelong treatment as is common with hormone-based diseases. Offering easy administration and no need for sterility which is cost effective, oral peptide delivery offers reduced invasiveness and better convenience compared to the traditionally used parental methods. For these reasons, the oral delivery of peptides remains an area of great interest for pharmaceuticals with the potential for much commercial and societal gain. 

The model peptide pasireotide was chosen for further modifications. Commercially known as Signifor®, pasireotide is a cyclohexapeptide analogue of endogenous somatostatin.  This project uses a multidirectional approach to move closer towards oral bioavailability.  The considerations for this project include determining factors that influence peptide permeability and enzymatic degradation as well as using in vitro activity assays to determine the extent of activity loss from peptide modifications.  Permeability and stereochemistry were found to highly impact in vitro permeability and stability with small changes eliciting large results.  Loss of key amino acids hinder peptide activity.  From these results, several modified peptides were deemed good candidates for further upcoming animal studies by demonstrating good in vitro permeability and high gastrointestinal and plasma stability.