Original Paper

Journal of Sol-Gel Science and Technology

, Volume 64, Issue 2, pp 324-334

Silica imprinted materials containing pharmaceuticals as a template: textural aspects

  • Everton C. MoraisAffiliated withInstituto de Química, Universidade Federal do Rio Grande do Sul
  • , Gabriel G. CorreaAffiliated withInstituto de Química, Universidade Federal do Rio Grande do Sul
  • , Rodrigo BrambillaAffiliated withInstituto de Química, Universidade Federal do Rio Grande do Sul
  • , Paolo R. LivottoAffiliated withInstituto de Química, Universidade Federal do Rio Grande do Sul
  • , João Henrique Z. dos SantosAffiliated withInstituto de Química, Universidade Federal do Rio Grande do Sul Email author 
  • , Mateus Borba CardosoAffiliated withLaboratório Nacional de Luz Síncrotron

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Abstract

Silica-based materials were prepared by the acid catalyzed sol–gel method using different pharmaceuticals as a template. The template molecules investigated were fluoxetine, gentamicin, lidocaine, morphine, nifedipine, paracetamol and tetracycline. The resulting hybrid silicas underwent ultrasound extraction in the presence of several solvents and were characterized by elemental analysis, porosimetry by adsorption/desorption of nitrogen (BET method), small-angle X-ray scattering and X-ray diffraction. Drug extraction was carried out by the combination of solvent and ultra-sound. The textural characteristics of the hybrid xerogels and resulting imprinted materials were shown to be highly dependent on the molecular weight and molecular volume of the drug template. Increasing the molecular weight of the template results in a decrease in the encapsulation content of the resulting material. In the case of paracetamol and fluoxetine, the dimensions of the surface area are not sufficient to guarantee the adsorption of the smaller molecule. Instead, the shape generated through encapsulation and extraction during the production of the imprinted silica dictates the adsorption behavior.

Keywords

Molecular imprinting Pharmaceuticals Silica Sol–gel Adsorption