Discovery of 3-OH-3-methylpipecolic hydroxamates: potent orally active inhibitors of aggrecanase and MMP-13.

A series of 3-hydroxy-3-methylpipecolic hydroxamate inhibitors of MMP-13 and aggrecanase was designed based on the observation of increased aggrecanase activity with substitution at the 3-position of the piperidine ring. Potency versus aggrecanase was optimized by modification of the benzyloxyarylsulfonamide group that binds in the S1' pocket. These compounds also possess markedly improved bioavailability and lower metabolic clearance compared to analogous 3,3-dimethyl-5-hydroxypipecolic hydroxamates. These improvements are attributed to lowered lipophilicity proximal to the metabolically labile hydroxamic acid. Synthesis, structure activity relationships, and in vivo efficacy data are described.

Discovery of 3,3-dimethyl-5-hydroxypipecolic hydroxamate-based inhibitors of aggrecanase and MMP-13.

A series of pipecolic hydroxamate inhibitors of MMP-13 and aggrecanase was discovered based on screening known inhibitors of TNF-alpha converting enzyme (TACE). Potency versus aggrecanase was optimized by modification of the benzyloxyarylsulfonamide group. Incorporation of geminal alkyl substitution at the 3-position of the piperidine ring improved metabolic stability, presumably by increasing steric hindrance around the metabolically labile hydroxamic acid. This modification also resulted in dramatic improvement of aggrecanase activity with a slight reduction in selectivity versus MMP-1. Synthesis, structure activity relationships, and strategies to reduce metabolic clearance are described.

3-Hydroxy-4-arylsulfonyltetrahydropyranyl-3-hydroxamic acids are novel inhibitors of MMP-13 and aggrecanase.

N-Hydroxy-3-hydroxy-4-arylsulfonyltetrahydropyranyl-3-carboxamides were designed as novel inhibitors of MMP-13 and aggrecanase based on known endocyclic hydroxamate inhibitors of matrix metalloproteinases. These compounds offer favorable physicochemical properties and low metabolic clearance. Synthesis and structure-activity relationships are reported.

Synthesis and biological activity of piperazine-based dual MMP-13 and TNF-alpha converting enzyme inhibitors.

A series of novel MMP-13 and TNF-alpha converting enzyme inhibitors based on piperazine 2-hydroxamic acid scaffolds are described. The TACE, MMP-1 and MMP-13 activity of these inhibitors as well as the effect of substitution of the piperazine nitrogen and the P-1' benzyloxy tailpiece is discussed. Moderate in vivo activity is observed with several members of this group.

Flavin-containing monooxygenase activity in hepatocytes and microsomes: in vitro characterization and in vivo scaling of benzydamine clearance.

Liver microsomes, and more recently cryopreserved hepatocytes, are commonly used in the in vitro characterization of the metabolism of new xenobiotics. The flavin-containing monooxygenases (FMO) are a major non p450 oxidase present in liver microsomes and hepatocytes. Since FMO is known to be thermally labile, and this enzyme may be involved in the metabolic clearance of some drugs, we sought to more completely characterize the metabolic competency of this enzyme in cryopreserved hepatocytes and in liver microsomes preincubated under various conditions using benzydamine as an in vitro and in vivo probe. The metabolism of benzydamine to its major metabolite, the N-oxide, is mediated by FMO3 in humans. We found that the in vitro microsomal t(1/2) was 70% longer when incubations were prewarmed at 37 degrees C in the absence of NADPH compared with prewarming in the presence of an NADPH-regenerating system, and N-oxide formation was inhibited >99%. Interestingly, the in vivo clearance predicted from these incubations and from human hepatocytes overpredicted the observed clearance of benzydamine in humans (>10.5 versus 2.4 ml/min/kg). In contrast, rat hepatocytes successfully predicted rat in vivo benzydamine clearance to within approximately 30% (>68 versus 48 ml/min/kg). Benzydamine N-oxidation in liver microsomes from all common preclinical species demonstrated heat sensitivity. This information should be considered when extrapolating metabolism data of xenobiotics from these in vitro systems.