Deproteinized natural rubber latex/gelatinized starch blended films as drug delivery carrier

Abstract

Deproteinized natural rubber (DNR) latex was blended to each of gelatinized potato, rice, and glutinous starch (GPS, GRS, and GGS, respectively) dispersions to construct a thin film with glycerin added as plasticizer. The appropriate blended films were selected to load lidocaine and used as drug delivery. It was found that dispersions of each gelatinized starch type provided different viscosities due to their amylose/amylopectin ratios. GRS dispersion could be blended with DNR latex up to 20 part per hundred of rubber (phr) because of its lowest viscosity. All gelatinized starch dispersions could be mixed with DNR latex to provide good film at the concentration of 5 phr. The percentage of moisture uptake and swelling ratio of these films increased causing the blending of gelatinized starch in DNR. The higher amounts of gelatinized starch increased the swelling ratio and volumetric swelling of blended film. The ultimate tensile strengths of these blended films were not different comparing to DNR film itself, but they had a tendency to raise up when the amounts of gelatinized starch increased. At 5 phr of gelatinized starch, GPS provided the highest percentage of elongation at break of blended film while GGS and GRS gave the lower values, respectively. Lidocaine could be mixed in DNR and 5 phr GRS blended films by simple mixing during film preparation process. The compatibility of these blended films was confirmed by their morphology, fourier transform infrared spectroscopy and differential scanning calorimeter. Amorphous pattern of drug in these films was detected by X-ray diffraction. Lidocaine release profile from this film showed the slow release for up to 90% in 12 h.