Objective. Inadvertent doping through the use of nutritional supplements is a potentially important cause of the increase in positive drug tests involving high-profile Olympic athletes. The aim of this study was to screen over-the-counter nutritional supplements for the presence of steroid or stimulant compounds banned by the International Olympic Committee (IOC) and the World Anti-Doping Agency (WADA). Method. Thirty different nutritional supplements from 14 different manufacturers were bought at shops in Bloemfontein, South Africa and analysed for testosterone and nandrolone prohormones, various ephedrines and caffeine. Results. Eighteen (60%) of the 30 supplements contained no prohibited substances. Of the 12 (40%) positive supplements, 8 (66.7%) contained prohormones and 4 (33.3%) contained stimulants. Six supplements contained prohormones, which were listed on the labels, while 2 contained prohormones not listed on the labels. The stimulants were listed on the labels as Ma Huang, Guarana and Kola extracts and all contained a mixture of ephedrines and caffeine. Conclusion. The results showed that approximately 7% of supplements tested may be mislabelled or contaminated with banned substances and that inadvertent doping through nutritional supplement use is a reality for athletes. The sporting community should therefore be aware that supplements might contain anabolic androgenic steroids and stimulants that are not declared on the labels. SA Sports Medicine Vol.16(2) 2004: 3-7

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a b s t r a c tThe IR and UV/visible kinetic results of the oxidative addition of iodomethane to Bu 4 N[Ir 2 (m-Dcbp) (CO) 2 (PCy 3 ) 2 ] (Dcbp ¼ 3,5-dicarboxylatepyrazolate anion) showed three time separable reactions. The first, very fast reaction corresponds to the a Ir(I)eIr(III) alkyl species formation within 10 À3 s. The second, relative fast reaction corresponds to Ir(III)eIr(III) alkyl formation with a rate constant of 3.25(4) Â 10 À2 M À1 s À1 while the third and slowest reaction corresponds to Ir(III)eIr(III) acyl formation with a rate constant of 1.42 Â 10 À5 s À1 . The IR data clearly show the existence of a number of equilibria with the formation of an Ir (I)eIr(III) alkyl product which then react to form the Ir(III)eIr(III) which then slowly react to form the Ir(III)eIr(III) acyl product. A solvent study indicated increased oxidative addition activity in the presence of polar solvents, which is indicative of a polar transition state. The large negative entropy of activation for the Ir(III)eIr(III) alkyl formation step (k 2 ) of À178(23) JK À1 mol À1 is indicative of an associative process. DFT calculations successfully identified the stereochemistry of the starting complex, [Ir 2 (m-Dcbp)(CO) 2 (PCy 3 ) 2 ] À as well as that of the Ir-alkyl and acyl isomers. A reaction pathway, using the IR data and DFT calculations, is proposed for the reaction.