Benzodiazepine receptor ligands: a patent review (2006-2012).

INTRODUCTION: Ligands at the benzodiazepine site of the GABA(A) receptor (GABA(A)-R) act by modulating the effect of GABA(A) (γ-aminobutyric acid). The selective modulator effects of such ligands are related to the α-subunits type (i.e., α1, α2, α3, and α5), being shown that the α1 subunit is associated with sedative, anticonvulsant and amnesic effects; whereas the α2 and α3 subunits mediate anxiolytic and myorelaxant effects. Recently it was shown the involvement of α5 subunit in pain relief, which is involved in cognitive processes of learning and memory. AREAS COVERED: This review covers patents, published from January 2006 to October 2012, on ligands for the benzodiazepine binding site of the GABA(A)-Rs. Patents filed from different companies and research groups report many series of compounds that may be used in the treatment or prevention of a large variety of neurodegenerative diseases. EXPERT OPINION: Most patents highlighted that various memory deficits, related to Alzheimer's disease, Down syndrome, mood disorders, schizophrenia, and age-related cognitive impairment may be treated using α5-selective ligands. Other aspects related to the use of allosteric modulators of the α7-nAchR and/or α5-GABA(A)-R (dual approach) for alleviating the impaired cognition and the use of α2-selective ligands for pain relief are highlighted, being particularly intriguing as new therapeutic approaches.