Oral dosage forms of oleanolic acid and their pharmacokinetics

Oleanolic acid (OA), a naturally occurring pentacyclic triterpenoid, is a biologically active marker compound commonly present in Chinese herbs, such as Fructus Ligustri Lucidi, Fructus Forsythiae and Radix Ginseng etc. Oleanolic acid has been successfully used as an OTC oral drug to treat human liver disorders in China due to its hepatoprotective effect. In addition, it exerts anti-inflammatory, antitumor and anti-hyperlipidemic effects. Up to now, the commonly used formulations of OA in the market are tablets, capsules, and pills. However, being hydrophobic, OA exhibits poor aqueous solubility and low bioavailability in vivo. The present review covers its physicochemical properties, dosage form development and pharmacokinetics studies. The difference between the application of these dosage forms, as well as the effectiveness of their improvements in OA's dissolution and oral bioavailability, are especially discussed.