Introduction: Lipoic acid (LA), a naturally occurring 1,2-dithiolane analog that plays an essential role in mitochondrial bioenergetic reactions, has gained unprecedented attention as nutritional supplement and as therapeutic agent. Moreover, LA conjugates with other pharmacophores represent a promising approach toward the development of multifunctional drugs.
Areas covered: The reviewed patent applications from January 2011 to April 2014 include combinations of LA with other bioactive compounds as well as LA conjugates for the treatment of a wide range of clinical conditions. Additionally, some patents disclose methods to overcome the stability problems of LA.
Expert opinion: LA is currently in clinical use for the treatment of diabetic neuropathy, while small clinical trials using combinations of LA with known bioactive agents have been undertaken. The use of the LA is hampered by its instability and its rapid metabolism. Thus, formulations containing LA, in a form ensuring its stability and improving its bioavailability, can have important applications as medicines, nutritional supplements or cosmeceuticals. LA hybrids with other pharmacophores endowed with various activities, possess an enormous potential to promote human health and have been the subject of numerous publications and patent applications. Nevertheless, reliable in vivo data and clinical trials are necessary to prove these beneficial effects.
Keywords: cancer; diabetes; inflammation; lipoic acid; lipoic acid conjugates; neurodegenerative diseases; nutraceuticals; pain.