Date of Award
Master of Science (MS)
Hassan Almoazen, Ph.D.
Isaac O. Donkor, Ph.D.; Duane D. Miller, Ph.D.
Peptides and proteins are imperative for the human body and play crucial roles in governing various bio-chemical processes. Recent advances in molecular biology and biochemistry helped in understanding the role of these endogenous macromolecules in different pathological and disease conditions. Currently, small molecule drugs (< 900dalton) in comparison to the therapeutic peptides and proteins-based drugs (TPP) dominate pharmaceutical market. However, the game is changing with the recent advances of biotechnological tools like recombinant DNA technology, solid phase protein synthesis etc., which enabled large-scale production of therapeutic peptides and proteins. The Success of Human Insulin, the first FDA approved commercial recombinant protein based therapeutic in 1982, revolutionized the field of TPPs. The number of FDA approved TPPs reached about to ~239 in 2017 compared to where it was only ~130 in 2008. Rapid progress in this sector can be attributed to several advantages of proteins and peptides over small molecule drugs both financially and clinically. From a clinical perspective, proteins and peptides are inherently more specific to the target site than the small molecules drugs, which lead to less interferences with normal biological system of the patient and caused minimal off-target side effects. A handful of proteins which are used for different clinical complications are less immunogenic because they are produced in the body naturally. Furthermore, proteins and peptides also take part in several complex and complicated biological processes, which is difficult to be to be mimicked by the small molecule drugs. From a financial standpoint, median total pre-market development times were shorter for biologics (10.6 years) than the small molecules drugs (12.6 years) estimated using Merck Index. In 2009, US Congress passed the Biologics Price Competition and Innovation Act (BPCIA) which gave new biologics 12 years of guaranteed exclusivity. The most commonly utilized routes for administering TPPs are I.V, I.P or I.M injections, which largely suffer from patient compliances. There are ~350 TPPs under clinical development and among them only 2 are given orally which is Interferon-α and Human growth hormone. Currently, most efforts in both industry and academia are centered around enhancing bioavailability of orally administered TPPs which typically are less than 1%. Oral administration is the non-invasive, most preferred route of drug administration for the patients. Furthermore, oral dosage forms are cheaper to manufacture as well as to administer, because they do not need to be produced under sterile conditions or administered in clinics. However, unfavorable physicochemical characteristics of TPPs like high molecular weight, hydrophilicity, poor stability in the physiological conditions, short biological half-life, low permeability through the epithelial barrier in the small intestine put up a massive barrier in the development of orally available dosage forms of TPPs. In this review, we will discuss the challenges associated with oral delivery of TPPs and the ongoing efforts to solve them.
Dan, Nirnoy (https://orcid.org/0000-0003-3335-9792), "An Update on Pharmaceutical Strategies for Oral Delivery of Therapeutic Peptides and Proteins" (2019). Theses and Dissertations (ETD). Paper 506. http://dx.doi.org/10.21007/etd.cghs.2019.0491.