Salcaprozate sodium (SNAC), an oral absorption promoter that was discovered as part of a screen to identify carrier-based permeation enhancers (Pes) that could “chaperone” poorly permeable payloads across the intestine. Its potential therapeutic application as a delivery agent was tested in many formats: taste-masked liquids, tablets, and soft gelatin capsules. SNAC is the most extensively tested carrier and the only PE approved in an oral formulation designed to improve oral bioavailabilities. The mechanism of action of this compound is not clear. However, Novo Nordisk offered a mechanism of action for SNAC in its non-enteric coated tablet of the glucagon-like peptide 1 analog, semaglutide. SNAC formed a complex around the semaglutide in the stomach and caused a transient increase in local pH around the molecule. It is claimed that semaglutide is protected against pepsin by SNAC and that solubility was increased, resulting in an increased concentration-dependent flux of semaglutide across the gastric mucosa, using a transcellular mechanism as the tablet comes in intimate contact with the epithelium. Clinical trials for patients with Type 2 Diabetes have shown that the oral semaglutide co-formulated with 300 mg SNAC could be used for further clinical development.

Cridanimod (Virexxa) is a small-molecule immunomodulator and interferon inducer, which, in preliminary studies, has been shown to increase progesterone receptor expression in endometrial tissue. Restoration of progesterone receptor expression may re-sensitize endometrial tumor tissue to progestin therapy in previously unresponsive tumors. Cridanimod was originally developed by Polysan and Pharmsynthez and licensed to Xenetic Biosciences. Virexxa is currently being studied in an ongoing Phase 2 multi-national study in conjunction with progestin therapy for the treatment of endometrial cancer in women with the recurrent or persistent disease who have failed progestin monotherapy.

Taurocholic acid is a bile acid and is the product of conjugation of cholic acid with taurine. Its sodium salt is the chief ingredient of the bile of carnivorous animals. Taurocholic acid, as with all bile acids, acts as a detergent to solubilize fats for absorption and is itself absorbed. It is used as a cholagogue and cholerectic (a bile purging agent). Hydrolysis of taurocholic acid yields taurine, a nonessential amino acid. Taurocholic acid is one of the main components of urinary nonsulfated bile acids in biliary atresia. Raised levels of the bile acid taurocholate in the fetal serum in obstetric cholestasis may result in the development of a fetal dysrhythmia and in sudden intra-uterine death. In medical use, it is administered as a cholagogue and choleretic. Taurocholic acid is a potent TGR5 ligand, and in dogs, colonic perfusion with TCA induces PYY secretion. TCA enemas could stimulate GLP-1 and PYY secretion in obese patients with type 2 diabetes receiving the dipeptidyl peptidase-4 (DPP-4) inhibitor, sitagliptin. Satiogen Pharmaceuticals is developing rectally administered taurocholic acid, a bile acid, for the treatment of obesity and type 2 diabetes mellitus.