title: Incorporation of NSAIDs in micelles: implication of structural switchover in drug-membrane interaction.
abstract: Non-steroidal anti-inflammatory drugs (NSAIDs) of oxicam group are not only effective as anti-inflammatory agents but also show diverse functions. Their principal targets are cyclooxygenases, which are membrane-associated enzymes. To bind with the targets these drugs have to pass through the membrane and hence their interactions with biomembranes should play a major role in guiding their interactions with cyclooxygenases. Here we have studied the interactions of three NSAIDs of oxicam group viz. piroxicam, meloxicam and tenoxicam with micelles having different headgroup charges, as simple membrane mimetic systems. Spectroscopic methods have been used to understand the interaction of these drugs with Cetyl N,N,N-trimethyl ammonium bromide (cationic), Sodium dodecyl sulphonate (anionic) and Triton X-100 (neutral) micelles. Our results demonstrate that the environment of the drugs i.e. the nature of the micelles plays a decisive role in choosing a specific prototropic form of the drugs for incorporation. Additionally it induces a switch over or change between different prototropic forms of piroxicam, which is correlated with the change in their reactivities in presence of different surface charges, given by the change in pK(a) values. These results together, indicate that in vivo, the diverse nature of biomembranes might play a significant role in choosing the particular form of oxicam NSAIDs that would be presented to their targets.
authors.affiliation: Chemical Sciences Division, Saha Institute of Nuclear Physics 1/AF, Bidhannagar, Calcutta 700 064, India.
authors.forename: Hirak
authors.initials: H
authors.lastname: Chakraborty
authors.forename: Rona
authors.initials: R
authors.lastname: Banerjee
authors.forename: Munna
authors.initials: M
authors.lastname: Sarkar
mesh_terms: D016880:Anisotropy; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D002593:Cetrimonium Compounds; D004347:Drug Interactions; D006863:Hydrogen-Ion Concentration; D000077239:Meloxicam; D008566:Membranes / Q000737:chemistry*; D008823:Micelles; D008958:Models, Molecular; D017830:Octoxynol; D010894:Piroxicam / Q000031:analogs & derivatives* / Q000737:chemistry; D011451:Prostaglandin-Endoperoxide Synthases / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate; D013053:Spectrophotometry / Q000379:methods; D013843:Thiazines / Q000737:chemistry; D013844:Thiazoles / Q000737:chemistry
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002593:Cetrimonium Compounds; D008823:Micelles; D013843:Thiazines; D013844:Thiazoles; D010894:Piroxicam; D012967:Sodium Dodecyl Sulfate; D017830:Octoxynol; D011451:Prostaglandin-Endoperoxide Synthases; D000077239:Meloxicam; C032801:tenoxicam