Journal
DRUG DEVELOPMENT AND INDUSTRIAL PHARMACY
Volume 45, Issue 1, Pages 67-75Publisher
TAYLOR & FRANCIS LTD
DOI: 10.1080/03639045.2018.1517776
Keywords
Thiomers; insulin; polymer-protein complexes; enzymatic degradation; oral protein delivery
Categories
Funding
- Institute for Health and Wellbeing Research, Robert Gordon University
- Scottish Overseas Research Scholarship Awards Scheme
Ask authors/readers for more resources
A significant barrier to oral insulin delivery is its enzymatic degradation in the gut. Nano-sized polymer-insulin polyelectrolyte complexes (PECS) have been developed to protect insulin against enzymatic degradation. Poly(allylamine) (Paa) was trimethylated to yield QPaa. Thiolation of Paa and QPaa was achieved by attaching either N-acetylcysteine (NAC) or thiobutylamidine (TBA) ligands (Paa-NAC/QPaa-NAC and Paa-TBA/QPaa-TBA thiomers). PEC formulations were prepared in Tris buffer (pH 7.4) at various polymer: insulin mass ratios (0.2:1-2:1). PECS were characterized by %transmittance of light and photon correlation spectroscopy. Insulin complexation efficiency and enzyme-protective effect of these complexes were determined by HPLC. Complexation with insulin was found to be optimal at mass ratios of 0.4-1:1 for all polymers. PECS in this mass range were positively-charged (20-40 mV), nanoparticles (50-200 nm), with high insulin complexation efficiency (>90%). Complexation with TBA polymers appeared to result in disulfide bridge formation between the polymers and insulin. In vitro enzymatic degradation assays of QPaa, Paa-NAC, and QPaa-NAC PECS showed that they all offered some protection against insulin degradation by trypsin and alpha-chymotrypsin, but not from pepsin. QPaa-NAC complexes with insulin are the most promising formulation for future work, given their ability to offer protection against intestinal enzymes. This work highlights the importance of optimizing polymer structure in the delivery of proteins.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available