As bioactive molecules, peptides and proteins are essential in living organisms, including animals and humans. Defects in their function lead to various diseases in humans. Therefore, the use of proteins in treating multiple diseases, such as cancers and hepatitis, is increasing. There are different routes to administer proteins, which have limitations due to their large and hydrophilic structure. Another limitation is the presence of biological and lipophilic membranes that do not allow proteins to pass quickly. There are different strategies to increase the absorption of proteins from these biological membranes. One of these strategies is to use compounds as absorption enhancers. Absorption enhancers are compounds such as surfactants, phospholipids and cyclodextrins that increase protein passage through the biological membrane and their absorption by different mechanisms. This review focuses on using other absorption enhancers and their mechanism in protein administration routes.

BACKGROUND: Deoxycholic acid (DOCA) is involved in many physiological functions and has been used in various fields of pharmaceutical formulations as a natural active solubilizing and permeation-enhancing agent. Although DOCA has been suggested to be a promoter of colon cancer, it has also been used extensively as a starting material to obtain new derivatives for potential therapeutic applications.
METHODS: In this review, we focus on patents and research reports from 2011 to 2014 related to pharmaceutical formulations and therapeutic applications using DOCA and its derivatives as surfactants or absorption enhancers, drug delivery carriers, and anti-cancer agents.
CONCLUSIONS: In recent few years, DOCA and its derivatives have been used mostly as pharmaceutical excipients for solubilizing lipophilic compounds to improve their bioavailability. Other studies have expanded its applications to include enhanced drug permeability and have designed more effective drug carriers by conjugation with polymeric materials. Recently, a synthetic DOCA injection, ATX-101, has shown long-term efficacy in the non-surgical treatment of unwanted submental fat and acceptable tolerability in humans. Thus, it may be used for reducing specific localized fat accumulations. Additionally, DOCA has been a starting material for anti-cancer drugs, and some derivatives showed strong inhibitory activities against several carcinoma cells.