1. A process for producing carbonate particles, comprising:
heating together a metal ion source and a carbonate ion source in a liquid at 55\xb0 C. or higher for reaction to produce carbonate particles with an aspect ratio of greater than 1, by using a hydrolysis of:
(NH2)2CO+2OH\u2212\u2192CO32\u2212+2NH3\u2003\u2003Equation (2),
wherein the metal ion source contains at least one metal ion selected from the group consisting of Sr2+, Ca2+, Ba2+, Zn2+ and Pb2+; and
wherein the pH of the liquid before heating is basic, and the pH of the liquid after heating is lowered to 8.20 or more.
2. The process for producing carbonate particles according to claim 1, wherein the carbonate particles are needle- or rod-shaped.
3. The process for producing carbonate particles according to claim 1, wherein the metal ion source contains at least one of NO3\u2212, Cl\u2212 and OH\u2212.
4. The process for producing carbonate particles according to claim 1, wherein the liquid contains water.
5. The process for producing carbonate particles according to claim 1, wherein the liquid contains a solvent.
6. The process for producing carbonate particles according to claim 5, wherein the solvent is at least one selected from the group consisting of methanol, ethanol, and isopropyl alcohol.
7. The process for producing carbonate particles according to claim 1, wherein in an X-ray diffraction spectrum of the carbonate particles, the full-width at half maximum of the diffraction peak corresponding to (111) plane is less than 0.8\xb0.
8. The process for producing carbonate particles according to claim 1, wherein the average particle length of the carbonate particles is 0.05 \u03bcm to 5 \u03bcm.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for preparation of microsphere from an emulsion wherein an organic phase containing an organic solvent having a boiling point lower than that of water and a hardly-water-soluble polymer is emulsified in an aqueous phase by an in-water drying method, which comprises:
(1) using an apparatus equipped with a gas separation membrane;
(2) supplying the emulsion to be subjected to in-water drying to one side of said gas separation membrane;
(3) evaporating off the organic solvent contained in said emulsion to the other side of said gas separation membrane.
2. The method for preparation of microsphere according to claim 1, wherein a medicament is contained in the organic phase.
3. The method for preparation of microsphere according to claim 2, wherein the medicament is contained in a ratio of 0.01 to 60% by weight based on the weight of the hardly-water-soluble polymer.
4. The method for preparation of microsphere according to claim 3, wherein in the medicament-containing organic phase, the medicament is directly dissolved or dispersed in a solution of the hardly-water-soluble polymer, or an aqueous solution of the medicament is dispersed in a solution of the hardly-water-soluble polymer, or the medicament is dissolved or dispersed in a dispersed solution of one hardly-water-soluble polymer, which solution is dispersed in a solution of another hardly-water-soluble polymer.
5. The method for preparation of microsphere according to any one of claims 1 to 4, wherein the hardly-water-soluble polymer is a hardly-water-soluble biodegradable polymer.
6. The method for preparation of microsphere according to claim 5, wherein the hardly-water-soluble biodegradable polymer is a polyester of a hydroxyfatty acid.
7. The method for preparation of microsphere according to claim 6, wherein the polyester of a hydroxyfatty acid is one or more members selected from a polylactic acid, a copolymer of lactic acid-glycolic acid, and a copolymer of 2-hydroxybutyric acid-glycolic acid.
8. The method for preparation of microsphere according to any one of claims 1 to 7, wherein the hardly-water-soluble polymer is contained in the organic phase in a concentration of 0.01 to 90% by weight.
9. The method for preparation of microsphere according to any one of claims 1 to 8, wherein the organic solvent having a boiling point lower than that of water is one or more members selected from a halogenated aliphatic hydrocarbon solvent, an aliphatic ester solvent, an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, a ketone solvent, and an ether solvent.
10. The method for preparation of microsphere according to claim 9, wherein the organic solvent has a boiling point lower by 15 to 60 C. than that of water under the evaporation conditions therefor.
11. The method for preparation of microsphere according to claim 9, wherein the organic solvent is one member selected from methylene chloride, chloroform and ethyl acetate.
12. The method for preparation of microsphere according to any one of claims 1 to 11, wherein the aqueous phase contains one or more members selected from an emulsifying agent, a polyethylene castor oil derivative, a polyvinylpyrrolidone, a polyvinyl alcohol, a carboxymethylcellulose, a methylcellulose, a lecithin, and a gelatin.
13. The method for preparation of microsphere according to any one of claims 1 to 12, wherein in the emulsion, the aqueous phase is contained in a volume of 1 to 10,000 times of the volume of the organic phase.
14. The method for preparation of microsphere according to any one of claims 1 to 13, wherein the gas separation membrane is a pervaporation membrane or a porous membrane.
15. The method for preparation of microsphere according to claim 14, wherein the gas separation membrane is a pervaporation membrane.
16. The method for preparation of microsphere according to claim 15, wherein the gas separation membrane is a silicon-rubber pervaporation membrane.
17. The method for preparation of microsphere according to any one of claims 14 to 16, wherein the gas separation membrane is used in the form of a bundle of plural gas separation membranes which form hollow fibers.
18. The method for preparation of microsphere according to any one of claims 1 to 17, wherein the evaporation of the organic solvent to the other side of the gas separation membrane is carried out by one means or a combination of means selected from passing a gas on said other side of the gas separation membrane, decompressing said other side of the gas separation membrane, or warming the emulsion which is supplied to one side of the gas separation membrane.
19. The method for preparation of microsphere according to claim 18, which is carried out by circulatively repeating the steps: taking out a portion of the emulsion; supplying the same to one side of the gas separation membrane; and then returning a resulting liquid after the evaporation of the organic solvent into the original emulsion.
20. The method for preparation of microsphere according to claim 19, wherein only a portion of the aqueous phase which is obtained by filtration of the emulsion is taken out, and then supplying the same to one side of the gas separation membrane.
21. The method for preparation of microsphere according to claim 19 or 20, wherein a bundle of plural gas separation membranes which form hollow fibers is used, and a portion of the emulsion for in-water drying is introduced into the inner side of said gas separation membranes which form hollow fibers and the organic solvent is evaporated to the outside of said gas separation membranes.
22. The method for preparation of microsphere according to claim 18, wherein the bundle of gas separation membranes which form hollow fibers is immersed in the emulsion, and then passing a gas on the inner side of said gas separation membranes which form hollow fibers to evaporate the organic solvent.
23. The method for preparation of microsphere according to any one of claims 1 to 22, wherein the organic solvent to be evaporated is recovered by cooling or by absorbing to a porous substance.
24. The method for preparation of microsphere according to any one of claims 1 to 23, wherein the preparation of microsphere by an in-water drying method is carried out in a closed system.
25. An apparatus for preparation of microsphere by an in-water drying method from an emulsion wherein an organic phase containing an organic solvent having a boiling point lower than that of water and a hardly-water-soluble polymer is emulsified in an aqueous phase, which consists of the following elements:
(a) a vessel for filling an emulsion;
(b) a gas separation membrane module for evaporating off an organic solvent from the emulsion;
(c) a circulation pathway which connects the vessel and the gas separation membrane module; and
(d) a pump for circulating the emulsion through the gas separation membrane module.
26. An apparatus for preparation of microsphere by an in-water drying method from an emulsion wherein an organic phase containing an organic solvent having a boiling point lower than that of water and a hardly-water-soluble polymer is emulsified in an aqueous phase, which consists of the following elements:
(a) a vessel for filling an emulsion; and
(b) a gas separation membrane module to be immersed in the emulsion in the vessel for evaporating an organic solvent from the emulsion.