title: Supramolecular dynamics of thalidomide and its derivatives in water-sediment system.
abstract: The 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 x 0.46 cm, particle size 50 microm) 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 days(-1) for S- and R-enantiomers, respectively. The uptake of thalidomide by sediment is quite good and of endothermic nature indicating good self-purification capacity of the nature for such toxic species.
authors.affiliation: Department of Chemistry, Jamia Millia Islamia (Central University), New Delhi, India. drimran_ali@yahoo.com
authors.forename: Imran
authors.initials: I
authors.lastname: Ali
authors.forename: Vinod K
authors.initials: VK
authors.lastname: Gupta
authors.forename: Hassan Y
authors.initials: HY
authors.lastname: Aboul-Enein
mesh_terms: D000327:Adsorption; D002623:Chemistry Techniques, Analytical; D002845:Chromatography / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D000431:Ethanol / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017633:Magnesium Silicates / Q000737:chemistry; D008956:Models, Chemical; D012964:Sodium / Q000737:chemistry; D013237:Stereoisomerism; D013792:Thalidomide / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry*; D013816:Thermodynamics; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D017633:Magnesium Silicates; D014867:Water; C005013:Florisil; D000431:Ethanol; D013792:Thalidomide; D012964:Sodium