Jeong-Wook Park

Preparation and characterization of drug-loaded polymethacrylate microspheres by an emulsion solvent evaporation method

Microspheres containing the anti-hypertension drug, felodipine, were prepared by the emulsion solvent evaporation method (o/o) using acrylate methacrylate copolymers, Eudragit RL PO and Eudragit RS PO, as wall materials. In order to increase the encapsulation efficiency, a mixed solvent system comprising 1:1 proportions of acetonitrile and dichloromethane was used as a dispersed phase. The morphology of the microspheres was evaluated using a scanning electron microscope, which showed a spherical shape with smooth surface. The mean sphere diameter was between 9.5-13.2 #119 m and the microencapsulation efficiencies ranged from 51.4-80.4%. The release profiles and encapsulation efficiencies depended strongly on the structure of the polymers used as wall materials. The release rate of the Eudragit RS PO microspheres was much lower than that of Eudragit RL PO microspheres. Whereas Eudragit RL PO microspheres followed the Higuchi rule, Eudragit RS PO microspheres exhibited a triphasic release profile. It is concluded that drug release rate can be controlled by choice of polymer type.

Salinity and Heavy Metal Contents of Solar Salts Produced in Jeollanamdo Province of Korea

To assess the safety of solar salts of Jeollanamdo province where most of Korean solar salts are produced, 433 samples of solar salts in total were collected and analyzed for their contents of sodium chloride and heavy metals (lead, cadmium, arsenic and mercury). Sodium chloride contents ranged from 80 to 85% in 63% of solar salts analyzed. Lead was not detected in 77% of solar salt samples and showed a value of below the maximum permissible limit (2 ppm) in other samples. Cadmium was not detected in most samples (78%), and the other samples where cadmium was detected showed a value far below the maximum permissible limit (0.5 ppm) except for three ones. Arsenic was detected in only four samples, but their concentrations were far below the permissible limit (0.1 ppm). Mercury was not detected in all samples. There were some differences between producing areas in the levels of sodium chloride and lead of solar salts, but the contents of cadmium, arsenic and mercury did not show significant regional differences. These results clearly indicate that solar salts produced from Jeollanamdo province are safe in the aspects of lead, cadmium, arsenic and mercury contents.