Thermodynamic characterization of dexamethasone sodium phosphate and its complex with dna as studied by conductometric and spectroscopic techniques

AFZAL SHAH ^[1] ; ASAD M KHAN ^[1] ; MUHAMMAD USMAN ^[1] ; RUMANA QURESHl ^[1] ; MUHAMMAD SIDDIQ ^[1] ; SYED S SHAH ^[1]
1. [1] Quaid-i-Azam University
  
  Quaid-i-Azam University
  
  Pakistán
Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 54, Nº. 2, 2009, págs. 134-137
Idioma: inglés
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Resumen
- Electrical conductivities were measured to calculate critical aggregation concentration (cac) of dexamethasone sodium phosphate (DSP) at various temperature from 298-313K with an increment of 5 K and in this way its thermodynamic parameters like Gibbs energy of aggregation ( ΔGagg), enthalpy of aggregation (ΔHagg ) and entropy of aggregation (ΔSagg) were estimated. The results demonstrate that DSP forms enthalpy driven aggregates through open association process. Furthermore, its interaction with DNA was studied by UV-Vis spectroscopy. The binding constant of DSP-DNA interaction was evaluated at 298 K and 310 K. Gibbs energy of drug-DNAcomplexation was determined by ΔG= -RT 1n k b , enthalpy of its interaction (ΔH) and entropy of adduct formation (ΔS) were obtained from Van't Hoff equation.