Original scientific paper
Dual Drug Release of Triamterene and Aminophylline from Poly (N-Isopropylacrylamide) Hydrogels
Emilio Castro
; Grupo de Fisica de Coloides y Polimeros, Departamento de Fisica de la Materia Condensada, Facultad de Fisica, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
Victor Mosquera
; Grupo de Fisica de Coloides y Polimeros, Departamento de Fisica de la Materia Condensada, Facultad de Fisica, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
Issa Katime
; Grupo de Nuevos Materiales y Espectroscopia Supramolecular, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Lejona, Spain
Abstract
We used temperature‐sensitive poly(N‐isopropylacrylamide) hydrogels as drug delivery systems, so changes in body temperature induced by pathogens could act like external stimuli to activate controlled release of the drugs incorporated in the hydrogel. In the distilled water combined release studies, we chose two model drugs: aminophylline and triamterene. The amount of drug released was measured by UV‐Vis spectroscopy following the evolution of the absorption peaks of aminophylline (271 nm) and triamterene (365 nm). The maximum release time was greater for triamterene than for aminophylline at 37 oC, so these time‐release profiles enabled the active ingredients to work over different periods of time. By increasing molar mass or solubility of the drug, we observed that the diffusion coefficient decreased. On the contrary, increasing hydrophobicity of the drug leads to a diffusion coefficient increase. The evolution of pore size distribution of hydrogels during loading and releasing was measured by quasi‐elastic light scattering and by environmental electronic scanning microscope. When loading and releasing the drugs, the pore size of the hydrogel decreased and increased again without reaching the initial pore size of the hydrogel, respectively. We observed that the greater the concentration of drug loaded into the hydrogel, the greater the reduction in pore size.
Keywords
drug delivery systems; polyamides; diffusion; UV-Vis spectroscopy
Hrčak ID:
142865
URI
Publication date:
1.1.2012.
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