Preparation Of Alginate Beads Research Articles

Sodium alginate-halloysite nanotube gel beads as potential delivery system for sunitinib malate anticancer compound

In this contribution, the preparation of alginate beads with different amount of halloysite nanotubes is described in the presence of Ca2+ ions as cross-linker. The synthesized beads, called SA-Haln, were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction powder (XRD), and thermogravimetric (TGA) technique. Furthermore, for the first time, the drug delivery performance of the beads was evaluated toward sunitinib malate, STM, as an anticancer model drug. The results showed that the incorporation of various amount of halloysite in the beads structure could be affected and modulated their properties remarkably. 80.4%, 65.6% and 58.4% STM encapsulation efficiency (EE %) were observed for SA-Hal 0, SA-Hal 5 and SA-Hal 10, respectively.

Preparation of alginate beads containing a prodrug of diethylenetriaminepentaacetic acid

Preparation of alginate beads containing a prodrug of diethylenetriaminepentaacetic acid

Preparation of alginate beads containing a prodrug of diethylenetriaminepentaacetic acid

A penta-ethyl ester prodrug of the radionuclide decorporation agent diethylenetriaminepentaacetic acid (DTPA), which exists as an oily liquid, was encapsulated in alginate beads by the ionotropic gelation method. An optimal formulation was found by varying initial concentrations of DTPA penta-ethyl ester, alginate polymer, Tween 80 surfactant and calcium chloride. All prepared alginate beads were ∼1.6mm in diameter, and the optimal formulation had loading and encapsulation efficiencies of 91.0±1.1 and 72.6±2.2%, respectively, and only 3.2±0.8% water absorption after storage at room temperature in ∼80% relative humidity. Moreover, Fourier transform infrared spectroscopy showed that DTPA penta-ethyl ester did not react with excipients during formation of the DTPA penta-ethyl ester-containing alginate beads. Release of prodrug from alginate beads was via anomalous transport, and its stability enhanced by encapsulation. Collectively, these data suggest that this solid dosage form may be suitable for oral administration after radionuclide contamination.

Removal of some nitrophenol contaminants using alginate gel beads

Biopolymers such as alginates are commonly used to remove the cationic contaminants from wastewaters. The major component of the alginate is the alginic acid, a linear, binary heteropolymer of β-d-mannuronate and α-l-guluronate residues. In this study the fundamental aspects in the preparation of alginate beads and the effects of salt, sodium alginate concentrations and two cationic surfactants (dodecyltrimethylammonium bromide, cetyltrimethylammonium bromide) on the domains of binding isotherms were investigated. The alginate cross-link complexes with metal ions can exist either as homogeneous clear solutions or precipitates or as spherical beads. The applicability of the calcium and calcium–iron alginate gel beads for removal of some nitrophenols from aqueous solutions was studied. The sorption and kinetic experiments were conducted under different values of pH, initial concentration of nitrophenols and the amount of alginate gel beads. The removal efficiency of contaminant increases with the increasing of the pH and the quantity of alginate beads and decreases with the increasing of initial contaminant concentration. The uptake of nitrophenols occurs rapidly in the first 12 h, followed by a slow process that takes about 72 h. According to the egg-box model of gelation mechanism the cavities formed in the alginate gel capture the cationic contaminants. The adsorption equilibrium data obtained for nitrophenols derivatives at various pH and initial solid sorbent amount were applied to the two classical models, i.e. Langmuir and Freundlich, and the isotherm parameters were calculated.

Novel solvent-based method for preparation of alginate beads with improved roundness and predictable size

Attempts to determine conditions or processes within alginate gel beads often suffer from inaccuracies due to an improper roundness of the analysed beads. Therefore, a novel solvent-based method for the preparation of alginate beads with improved shape was developed: An aqueous solution of 2% (w/v) alginate in water was injected into a solvent layering consisting of hexane, n-butanol, n-butanol with 1% (w/v) CaCl2 and finally 2% (w/v) CaCl2 in water. Beads of up to 3.5 mm in diameter obtained with this method had a roundness which was ∼5% better than comparable beads prepared by dropping an alginate solution into a CaCl2-hardening bath. This was determined by a software supported quantitative analysis of bead size and shape. Additionally, the novel solvent-based method allows for highly reproducible preparation of alginate beads with exactly predictable sizes. The biggest beads obtained with this method were 9 mm in diameter. Thus, with the solvent-based preparation of alginate beads it is now possible to easily obtain beads of exactly the type needed for a specific analytical purpose.