isoxicam and Inflammation

Oxicams are a class of nonsteroidal anti-inflammatory drugs (NSAIDs) structurally related to the enolic acid class of 4-hydroxy-1,2-benzothiazine carboxamides. They are used clinically to treat both acute and chronic inflammation by inhibiting the activity of the two cyclooxygenase (COX) isoforms, COX-1 and COX-2. Oxicams are structurally distinct from all other NSAIDs, exhibiting a novel binding pose in the COX active site. The 4-hydroxyl group on the thiazine ring partners with Ser-530 via hydrogen bonding while two coordinated water molecules mediate a polar interaction between the oxicam and COX. The rotation of Leu-531 in the complex opens a new pocket, which is not used for binding other NSAIDs to the enzyme. This structure provides the basis for understanding documented structure-activity relationships within the oxicam class. In addition, from the oxicam template, a series of potent microsomal prostaglandin E synthase-1 (mPGES-1) inhibitors represents a new direction for drug development. Here, we review the major route of oxicam synthesis and structure-activity for COX inhibition, as well as recent advances in oxicam-mediated mPGES-1 inhibition.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Humans; Inflammation; Intramolecular Oxidoreductases; Meloxicam; Piroxicam; Prostaglandin-E Synthases; Thiazines; Thiazoles

This protocol describes microsphere-based protease assays for use in flow cytometry and high-throughput screening. This platform measures a loss of fluorescence from the surface of a microsphere due to the cleavage of an attached fluorescent protease substrate by a suitable protease enzyme. The assay format can be adapted to any site or protein-specific protease of interest and results can be measured in both real time and as endpoint fluorescence assays on a flow cytometer. Endpoint assays are easily adapted to microplate format for flow cytometry high-throughput analysis and inhibitor screening.

Topics: Animals; Biotinylation; Flow Cytometry; Fluorescence Resonance Energy Transfer; Green Fluorescent Proteins; High-Throughput Screening Assays; Humans; Inflammation; Kinetics; Microspheres; Peptide Hydrolases; Peptides; Reproducibility of Results; Temperature

Isoxicam is a potent, orally active, nonsteroidal anti-inflammarory drug with prolonged activtiy in experimentally induced inflammation in rats. Isoxicam is less ulcerogenic, acutely less toxic and, therefore, appears to have a therapeutic ratio superior to other standard agents to which it was compared.

Topics: Animals; Anti-Inflammatory Agents; Arthritis, Experimental; Carrageenan; Inflammation; Isoxazoles; Male; Oxazoles; Peptic Ulcer; Piroxicam; Rats; Thiazines