Thermodynamic process of theophylline adsorption in vitro on to activated carbon in simulated gastric fluid

Authors

  • Carlos A. Rey-Mafull Instituto de Ciencia y Tecnología de Materiales (IMRE-UH), La Habana
  • Julio César-LLópiz Instituto de Ciencia y Tecnología de Materiales (IMRE-UH), La Habana
  • Dachamir Hotza Instituto de Ciencia y Tecnología de Materiales (IMRE-UH), La Habana
  • Raquel García-Gallardo Instituto de Ciencia y Tecnología de Materiales (IMRE-UH), La Habana

Abstract

The in vitro adsorption of theophylline onto seven selected materials (NB, NE, BDH, Ch3J, Merck, Panreac, ML) was studied in simulated gastric fluid at pH 1.2 and 4 h by using shaker water bath within a temperature range 300 to 317 K in batch experiments. The experimental adsorption was fitted by eight isotherms models: Langmuir Type I and II, DR, Halsey, Freundlich, Harkins-Jura, Temkin and BET. Materials were characterized by pHzpc, and N2 77 K. The best linear (R2=098) and non linear (R2=0.95, RAMSE=43) fittings of isotherms models were obtained with Langnuir TI which assumes monolayer adsorption and specific interactions. The theophylline adsorption was controlled by chemisorptions and exothermically process (∆H = -36.81-88.70 kJ/mol) with maximal capacity, qm (316-587 mg/g). The ΔG<0 indicate the spontaneous character and more favourable at lower temperature. ΔS<0 suggests a decrease in the order of the adsorbed system with losses of freedom willingly.

Keywords: activated carbon, theophylline, thermodynamic parameters, adsorption isotherms.

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Published

2016-05-26

How to Cite

Rey-Mafull, C. A., César-LLópiz, J., Hotza, D., & García-Gallardo, R. (2016). Thermodynamic process of theophylline adsorption in vitro on to activated carbon in simulated gastric fluid. Revista Cubana De Química, 28(2), 625–644. Retrieved from https://cubanaquimica.uo.edu.cu/index.php/cq/article/view/1148

Issue

Vol. 28 No. 2 (2016)

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Artículos

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