Buprenorphine - an attractive opioid with underutilized potential in treatment of chronic pain.

Despite proven clinical utility, buprenorphine has not been used widely for the treatment of chronic pain. Questions about "ceiling effect" or bell-shaped curve observed for analgesia in preclinical studies and potential withdrawal issues on combining with marketed µ-agonists continue to hinder progress in expanding full potential of buprenorphine in the treatment of cancer and noncancer pain. Mounting evidence from clinical studies and conclusions drawn by a panel of experts strongly support superior safety and efficacy profile of buprenorphine vs marketed opioids. No ceiling on analgesic effect has been reported in clinical studies. The receptor pharmacology and pharmacokinetics profile of buprenorphine is complex but unique and contributes to its distinct safety and efficacy. The buprenorphine pharmacology also allows it to be combined with other µ-receptor opioids for additivity in efficacy. Transdermal delivery products of buprenorphine have been preferred choices for the management of pain but new delivery options are under investigation for the treatment of both opioid dependence and chronic pain.

Fatty acid amide hydrolase inhibitors--progress and potential.

Fatty acid amide hydrolase (FAAH) is responsible for hydrolysis of endocannabinoid, anandamide (AEA), and N-acyl ethanolamines such as palmitoylethanolamine (PEA) and N-oleoylethanolamide (OEA). Genetic deletion or pharmacological inactivation of FAAH shows site-specific elevation of AEA that plays a role in the modulation of pain and other neurodegenerative disorders. The review elaborates recent progress and current status of diverse structural classes of reversible and irreversible FAAH inhibitors. The discussion also addresses ligand-enzyme active site interactions and mechanism of enzyme inactivation, emerging approaches to novel FAAH inhibitors, and ongoing efforts to address gaps in therapeutic utility of FAAH inhibitors.

Discovery of +(2-{4-[2-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)ethoxy]phenyl}-cyclopropyl)acetic acid as potent and selective alphavbeta3 inhibitor: design, synthesis, and optimization.

The integrin alpha(v)beta(3) is expressed in a number of cell types and is thought to play a major role in several pathological conditions. Various small molecules that inhibit the integrin have been shown to suppress tumor growth and retinal angiogenesis. The tripeptide Arg-Gly-Asp (RGD), a common binding motif in several ligands that bind to alpha(v)beta(3), has been depeptidized and optimized in our efforts toward discovering a small molecule inhibitor. We recently disclosed the synthesis and biological activity of several small molecules that did not contain any peptide bond and mimic the tripeptide RGD. The phenethyl group in one of the lead compounds was successfully replaced with a cyclopropyl moiety. The new lead compound was optimized for potency, selectivity, and for its ADME properties. We describe herein the discovery, synthesis, and optimization of cyclopropyl containing analogs that are potent and selective inhibitors of alpha(v)beta(3).

Convergent, parallel synthesis of a series of beta-substituted 1,2,4-oxadiazole butanoic acids as potent and selective alpha(v)beta3 receptor antagonists.

We describe a series of 1,2,4-oxadiazoles, which are potent antagonists of the integrin alpha(v)beta3 and, in addition, show selectivity relative to the other beta3 integrin alpha(IIb)beta3. In whole cells, the majority of these analogs also demonstrated modest selectivity against other alpha(v) integrins such as alpha(v)beta1 and alpha(v)beta6.