| Abstract: | The morphology and virus localization were studied in the microcapsulated measles vaccine formulation involving polyacrylic acid (PAA) copolymers as a matrix. Transmission electron microscopy and phosphotungsic staining at a pH value of 2 to 7 showed that the morphology of microparticles was related to the value of pH and to the concentration of a polymer in the matrix. In the neutral medium, the microcapsules had the sizes of 0.5 to 10 microm, which were optimal for transport through the intestinal wall when immunization was orally used. Immunocytochemistry revealed measles virus antigen within the microparticles. The specific activity of the microcapsulated formulation of measles virus was as high as 3.36 and 4.31 lg of TCD50/0.5 ml for the samples containing 1 and 0.1% polymer, respectively. The findings suggest that the microparticles of the vaccine contain live measles virus. |
