Preparation and physical characterization of alginate microparticles usingair atomization method

Alginate microparticles were prepared using an air atomization method and v arying formulation and processing conditions. Thereafter the size and surfa ce morphology of alginate microparticles were characterized The trapping ef ficiencies of the ketoconazole, acetaminophen, vitamin C, and Bifidobacteri a bifidum as model core materials were then determined. The air atomization process produced free;Rowing and small-size microparticles after the freez e-drying process. The size distribution and surface morphology varied depen ding on the concentration of wall-forming materials and processing conditio ns. Generally, the geometric mean size increased as the concentration of al ginate and poly-l-lysine and the delivery rate increased but the ail pressu re decreased. Most of all, the ratio of delivery rate of alginate solution and air pressure could affect the size and surface morphology of alginate m icroparticles. However the geometric mean size of alginate poly-l-lysine mi croparticles reproducibly ranged from about 80 to 130 mum. The microparticl es were irregularly spherical or elliptical. The trapping efficiencies of k etoconazole, acetaminophen, vitamin C, and bifidobacteria were determined t o be 71.5%, 60.1%, 1.6%, and 31%, respectively, when alginate concentration (1.5%), poly-l-lysine concentration (0.02%), air pressure (0.75 bar), deli very rate (8 ml/min), and spraying distance (45 cm) were applied. The curre nt microencapsulation process using the air atomization method provides an alternative to entrapping small molecules and macromolecules without using harmful organic solvents. In addition, the small-size and free-flowing algi nate microparticles containing active substances can be used as an intermed iate in pharmaceutical application.