Related Experiment Video
Updated: Jul 5, 2025

Direct Protein Delivery to Mammalian Cells Using Cell-permeable Cys2-His2 Zinc-finger Domains
Published on: March 25, 2015
The Current and Promising Oral Delivery Methods for Protein- and Peptide-Based Drugs
Michał Nicze1, Maciej Borówka1, Adrianna Dec1
1Department of Internal Medicine and Clinical Pharmacology, Faculty of Medical Sciences, Medical University of Silesia in Katowice, Medyków 18, 40-752 Katowice, Poland.
Abstract:
Drugs based on peptides and proteins (PPs) have been widely used in medicine, beginning with insulin therapy in patients with diabetes mellitus over a century ago. Although the oral route of drug administration is the preferred one by the vast majority of patients and improves compliance, medications of this kind due to their specific chemical structure are typically delivered parenterally, which ensures optimal bioavailability. In order to overcome issues connected with oral absorption of PPs such as their instability depending on digestive enzymes and pH changes in the gastrointestinal (GI) system on the one hand, but also their limited permeability across physiological barriers (mucus and epithelium) on the other hand, scientists have been strenuously searching for novel delivery methods enabling peptide and protein drugs (PPDs) to be administered enterally. These include utilization of different nanoparticles, transport channels, substances enhancing permeation, chemical modifications, hydrogels, microneedles, microemulsion, proteolytic enzyme inhibitors, and cell-penetrating peptides, all of which are extensively discussed in this review. Furthermore, this article highlights oral PP therapeutics both previously used in therapy and currently available on the medical market.
Related Concept Videos
Drug Delivery: Overview
Enteral delivery involves administering drugs directly through swallowing, sublingual placement, or buccal application. Orally administered drugs predominantly navigate the...
Drug Delivery: Miscellaneous Routes
Oral inhalation and nasal sprays swiftly transfer drugs across the respiratory epithelium's mucosal layer. Inhaled glucocorticoids and bronchodilators directly target lung conditions such as asthma, while fluticasone nasal spray mitigates allergic rhinitis.
Transdermal patches transport drugs...
Drug Delivery: Enteral Route
Routes of Drug Administration: Enteral
Enteral administration involves drug administration via the mouth in two ways: orally or sublingually.
Unlike sublingually drugs, drugs that are taken orally pass through the gastrointestinal (GI) tract and get metabolized by the liver. Once metabolized, the drug is absorbed into the systemic circulation, reaching different body parts via the bloodstream. However, while passing through the stomach,...
Drug Delivery: Parenteral Route
There are three primary parenteral routes: intravenous (IV), intramuscular (IM), and subcutaneous (SC). The IV route introduces the drug directly into the bloodstream, ensuring immediate action. The IM route...
Routes of Drug Administration: Parenteral
The intravenous route (IV) of drug administration can be further categorized into two types. The bolus injection administers the entire dose rapidly, while an intravenous infusion slowly delivers smaller doses steadily.
The IV route is often...

