Preparation and structural characterization of O-acetyl agarose with low degree of substitution

Abstract

Among the biodegradable polymers, the polysaccharides have been found to be promising carriers for bioactive molecules. From a general standpoint, they present several reactive groups, such as hydroxyl, carboxyl and amine, that can be modified in a number of ways, giving rise to suitable devices for controlled release. In this paper, agarose was submitted to O-acetylation reactions under heterogeneous conditions, using acetic anhydride and pyridine, aiming to observe the effect of acetyl groups on the agarose properties. The products were characterized by Infrared and ¹H NMR spectroscopies. In the range of average acetylation degrees (DA) 0.07-0.48, the polymers presented partial solubility in boiling water and in common organic solvents. The ¹H NMR spectra presented evidences of non-homogeneous acetyl group distribution along the chains, as concluded from the solubility of only one of the fractions with DA<0.09, in boiling water

Preparation of berbamine loaded chitosan-agarose microspheres and in vitro release study

“…in the primary amine of chitosan (Figure 2a) [14] , but they were weaken in chitosan-agarose microspheres and the new absorption band at 1650 cm -1 appeared (Figure 2d), which could be attributed to the interaction between the -CHO groups of glutaraldehyde and the -NH 2 groups of chitosan in microspheres [15] . As shown in Figure 2b, the characteristic absorption bands of agarose were observed at 1076 cm -1 (C-O, axial deformation), 933 cm -1 (characteristic of 3, 6-anhydrogalactose) and 889 cm -1 (attributed to C-H angular deformation of anomeric carbon) [16] . Pure berbamine spectra showed the characteristic absorption bands at 1515, 1275 and 1117 cm -1 (Figure 2c) [17] , which also appeared in the spectra of berbamine loaded chitosan-agarose microspheres (Figure 2e) at the same wavenumbers suggesting no interactions between the drug and the carrier.…”

Physical Properties and Characterization of Cassava Peel Waste Modified by Esterification

“…The spectra obtained then calculated its DS value by following the Garcia and Vidal equation below [10] :…”

Study on Esterification Reaction of Starch Isolated from Cassava (Manihot Esculenta) with Acetic Acid and Isopropyl Myristate Using Ultrasonicator

“…The results of esterification reaction are analyzed by infrared spectrophotometry. Based on research Garcia and Vidal [14], the DS value was determined by FTIR spectra with the formula:…”