0022-4766/11/52 Supplement-0137 © S137 Journal of Structural Chemistry, Vol. 52, Supplement, pp. S137-S144, 2011 Original Russian Text Copyright © 2011 by А. I. Nizovskii, А. V. Kalinkin, T. P. Shakhtshneider, M. A. Dyakonova, S. A. Myz, E. V. Boldyreva, and Rakesh Kumar XPS STUDY OF PHARMACOLOGICAL SUBSTANCES MECHANOCHEMICALLY IMMOBILIZED ON THE SURFACE OF ALUMINA А. I. Nizovskii, 1 А. V. Kalinkin, 1 T. P. Shakhtshneider, 2,3 M. A. Dyakonova, 3 S. A. Myz, 2,3 E. V. Boldyreva, 2,3 and Rakesh Kumar 4 UDC 544-16 539.2:54 Piroxicam and meloxicam nanocomposites with alumina were synthesized by mechanochemical treatment of medicinal substances mixed with the oxide. X-ray photoelectron spectroscopy demonstrated that interaction of the components during mechanical activation proceeds via binding the amide and sulfate groups in the molecules of medicinal substances with the active sites of alumina surface. XPS studies confirmed the formation of “core–shell” composites with the shell represented by medicinal substances distributed over the support surface. Keywords: mechanochemistry, nanocomposites, X-ray photoelectron spectroscopy, medicinal substances, piroxicam, meloxicam, alumina. INTRODUCTION In recent years, hybrid organic-inorganic materials have attracted research attention due to diversity of their properties [1]. Being the “core–shell” nanocomposites, they possess unique features and can be used in various fields of science and technology, in particular, pharmacy. Among numerous techniques employed for synthesis of such materials, of special interest are mechanochemical methods, which do not require the application of organic solvents and heating to high temperatures. Although mechanical action on the mixtures of solid substances is now widely used in practice — to alter the properties of substances (solubility, catalytic activity, etc.) and produce novel materials, the nature of interaction between phases and mechanisms of mechanochemical reactions are still insufficiently understood [2]. In its turn, the interaction of medicinal substances with auxiliary substances (excipients) is considered in pharmacy [3, 4], because control of such interactions allows affecting the stability and biological availability of preparations. The interaction of medicinal substances with excipients is commonly investigated by means of vibrational spectroscopy [3, 5], thermal analysis [4, 6], and more rarely by NMR spectroscopy [7] and some other methods. To our knowledge, X-ray photoelectron spectroscopy (XPS) has not been used as yet for investigation of the medicinal substance — excipient systems. The present work deals with the interaction of components with alumina in the hybrid organic-inorganic composites of medicinal substances obtained by mechanical treatment — piroxicam and meloxicam — studied by XPS. 1 G. K. Boreskov Institute of Catalysis, Siberian Division, Russian Academy of Sciences, Novosibirsk; alexniz@inbox.ru. 2 Institute of Solid State Chemistry and Mechanochemistry, Siberian Division, Russian Academy of Sciences, Novosibirsk; 3 Scientific-Educational Center “Molecular Design and Environmentally Safe Technologies” at the Novosibirsk State University, Novosibirsk. 4 National Metallurgical Laboratory, Jamshedpur, India. Translated from Zhurnal Strukturnoi Khimii, Vol. 52, Supplement, pp. S141-S147, 2011. Original article submitted October 26, 2010.