Sustained release of a model macromolecule from preparations with erodible core

Hasırcı, Vasıf Nejat
Kamel , Ibrahim
A series of sustained release tablets were prepared which consisted of a water-soluble core and a highly hydrophobie coat. Release of a macromolecule. Spectrum Orange, from this preparation was studied. It was found that release was controlled by the coat composition and coating solution viscosity. SEM and optical microscopy of the tablets indicated that the coats contained pores on the surface which penetrated in towards the centre of the core. It was deduced that the almost zero order release of macromolecules from these tablets was basically through these pores and not by diffusion through the polymer matrix.


SUNGUR, S; ELCIN, YM; Akbulut, Ural (Elsevier BV, 1992-01-01)
Urease enzyme was immobilized in photographic gelatin by chemical cross-linking using formaldehyde, glutaraldehyde and chromium (III) acetate. The effects of enzyme and cross-linker concentrations, temperature, incubation time and pH on urea hydrolysis were investigated. Effect of reuse on the activity of immobilized enzyme was also studied. Glutaraldehyde (0.004 M) was the most suitable cross-linker; relative activities within 2.5 months after 24 reuses were stable (about 78%).
BAYRAMOGLU, Z; Akbulut, Ural; SUNGUR, S (Elsevier BV, 1992-01-01)
Alpha-amylase was immobilized into photographic gelatin by chemical cross-linking with chromium (III) acetate and chromium (III) sulphate. Cellulose triacetate film strips, enabled simple handling when coated with an alpha-amylase-gelatin mixture, accomplishing a high degree of durability during consecutive immersions into reaction media. The optimum conditions for pH, substrate concentration, temperature, incubation time and storing conditions of free and immobilized alpha-amylase were determined. The effe...
Immobilization of yeast cells in acrylamide gel matrix
Hasirci, V.N.; Alaeddinoglu, G.; Aykut, Gül (Elsevier BV, 1988-3)
Entrapment of yeast cells in a three-dimensional polymer matrix was achieved, and various properties of the polymer matrix as well as the invertase activity of the yeast cells were studied. When the matrix was highly cross-linked or synthesized from concentrated polymer solutions, its swelling ratio decreased. Invertase activity was found to increase with water content of the matrix. Cell content of the gel was found to affect adversely enzyme activity. The enzyme was found to retain its activity after seve...
Low-temperature chemical synthesis of lanthanum monoaluminate
Taspinar, E; Tas, AC (Wiley, 1997-01-01)
One of the promising candidates for ferroelectric substrate materials, lanthanum monoaluminate (LaAlO3), was successfully synthesized by two separate chemical powder preparation techniques: (i) homogeneous precipitation from aqueous solutions containing urea (CH4N2O) in the presence of nitrate salts, and (ii) self-propagating combustion synthesis from aqueous solutions containing CH4N2O and the respective nitrate salts of lanthanum and aluminum. The submicrometer, spherical-like particles of the precursors ...
Immobilization of glucose oxidase in poly(2-hydroxyethyl methacrylate) membranes
Arica, Y.; Hasirci, V.N.; Arica, Yakup (Elsevier BV, 1987-11)
Glucose oxidase (GOD) was immobilized in a poly(2-hydroxyethyl methacrylate) (HEMA) membrane through matrix entrapment in order to investigate the effect of various parameters (e.g. concentration of ingredients, temperature, repeated interaction with glucose and shelf storage) on the activity of the enzyme. Permeability of the membrane to a model permeant was tested and SEMs were obtained. It was observed that upon immobilization the affinity of GOD towards glucose was substantially decreased, and increasin...
Citation Formats
V. N. Hasırcı and I. Kamel, “Sustained release of a model macromolecule from preparations with erodible core,” Biomaterials, pp. 424–428, 1988, Accessed: 00, 2020. [Online]. Available: