Biomedical subjects

N Muramatsu

Publications and source records attributed to N Muramatsu.

60 records · Page 4Linked to original sources

PubMedDate not supplied

A study on the thermostability of microencapsulated glucose oxidase.

Glucose oxidase was microencapsulated within polyurea membranes by the interfacial polymerization method and the stability to heat of the encapsulated enzyme was examined. Thermostability of microencapsulated glucose oxidase was prominent and increased with increase in the amount of glucose oxidase entrapped. This stability, however, could not be ascribed to the peculiar properties of microcapsules but was suggested to be caused by the incorporation of glucose oxidase molecules in the membranes through chemical bonding. This stability revealed that the enzyme molecules in the microcapsules could not always exist in the dissolved form but a fairly large portion of the molecules participated in the polymerization reaction and changed their enzymatic properties.

Drug Compounding↗

PubMedDate not supplied

Electrostatic interaction of microcapsules with guinea-pig polymorphonuclear leucocytes.

Electrostatic interaction of microcapsules with guinea-pig polymorphonuclear leucocytes was investigated at different ionic strengths of the medium through measurements of the degree of phagocytosis by the cells of microcapsules. At any ionic strength, the interaction exhibited a maximum when the surface potential of microcapsules was equal to that of the leucocytes to make phagocytosis of microcapsules by the cells minimum. The experimental findings were analyzed by a novel model for the electrostatic interaction between ion-penetrable membranes. In this analysis, it was assumed that the leucocytes have an area (or areas) which permits cations to partition much more into the membrane than anions on their surface to reduce the electric potential of the area.

Animals↗

PubMedDate not supplied

Preparation of polyamide microcapsules having narrow size distributions.

A novel emulsification technique which employs microporous glass membranes was adopted to prepare polyamide microcapsules of narrow size distribution. This technique proved to be simple and quite efficient for getting fairly uniform sizes of dispersed liquid droplets. Polyamide microcapsules prepared by using this technique were found not completely monodisperse, but far more satisfactory than those by any conventional mechanical methods in view of their narrow size distribution. This method also seems promising to get various sizes of the capsules by selecting the pore size of the glass membranes.

Capsules↗

PubMedDate not supplied

An approach to prepare microparticles of uniform size.

A novel emulsification method which employs a glass membrane of controlled pore size was adopted to prepare various types of microparticles. The microparticles thus obtained were uniform in size and the procedure proved applicable to a wide variety of microencapsulation processes. Furthermore, the particle size could be controlled by selecting preparative conditions.

Alginates↗

PubMedDate not supplied

Effects of preparation conditions on the monodispersity of albumin microspheres.

Monodisperse albumin microspheres were successfully prepared by both chemical or thermal hardening methods via membrane emulsification using microporous glass membranes with uniform pore sizes. The monodispersity of the microspheres was found to depend strongly on parameters such as albumin concentration, emulsifier concentration, and volume ratio of the internal aqueous phase (albumin solution) to the dispersion medium (organic solvent). The optimum conditions for obtaining monodisperse albumin microspheres are described.

Chemistry, Pharmaceutical↗

PubMedDate not supplied

A novel method to prepare monodisperse microparticles.

The membrane emulsification method was adopted to prepare monodisperse albumin microspheres. Uniform-sized emulsion droplets were successfully obtained by passing albumin solution through the membrane into kerosene at appropriate applied pressures. After heating the emulsion, monodisperse albumin microspheres were prepared and the heat-denaturing process itself did not affect their monodispersity once uniform emulsion droplets had been prepared. The shape and size of the albumin microspheres were strongly dependent on the concentration of the albumin solution and the heat denaturing temperature. Lower albumin concentrations produced non-spherical particles and higher denaturing temperatures made the particles smaller. Incorporated riboflavin released quite rapidly from the albumin microspheres, and increases in both albumin concentration and denaturing temperature caused the drug release to be sustained, presumably because a rigid and dense matrix was formed within the albumin microspheres.

Albumins↗