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EXPERIMENTAL INVESTIGATION AND MODELING OF PRESTRESSED PRECAST HOLLOW-CORE SLABS WITH A STRUT-AND-TIE MODEL
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Supramolecular Dynamics of Thalidomide and its Derivatives in Water-Sediment System
Get PDFThe contamination of drug residues, including chiral ones, is not acceptable in earth’s ecosystem. The dynamicity of enantiomers of thalidomide and its derivatives (3-methyl thalidomide, 3-ethyl thalidomide, and 3-butyl thalidomide) was ascertained at supramolecular level in water-sediment system using solid phase extraction (SPE) and stereoselective HPLC. Enantiomeric separation of these drugs was carried out on Ceramosphere RU-2 (25 cm 3 0.46 cm, particle size 50 lm) chiral column using pure ethanol (1.0 ml/min) as eluent at 230 nm detection. Retention times, capacity, separation, and resolution factors of the enantiomers of these drugs were in the range of 20.0–36.0, 2.08–3.93, 1.35–1.57, and 1.0–2.0 min, respectively. Percentage recoveries of the enantiomers in SPE were in the range of 90.0 to 95.0 in water-sediment system. Langmuir and Freundlich model were best fitted for dynamic equilibrium concentrations at different experimental parameters. Thalidomide and its derivatives follow first-order kinetics at dynamic equilibrium. The rate constants of chiral interconversions were 0.390 and 0.385 days21 for S- and R-enantiomers, respectively. The uptake of thalidomide by sediment is quite good and of endothermic nature indicating good self-purifi-cation capacity of the nature for such toxic species. Chirality 00:000–000, 2009. VVC 2009 Wiley-Liss, Inc
