SILICA SOL MATERIAL HAVING AT LEAST ONE THERAPEUTICALLY ACTIVE SUBSTANCE FOR PRODUCING BIOLOGICALLY DEGRADABLE AND/OR RESORBABLE SILICA GEL MATERIALS FOR HUMAN MEDICINE AND/OR MEDICAL TECHNOLOGY
The invention relates to a novel silica sol material containing at least one therapeutically active ingredient and its use for the production of bioabsorbable and biodegradable silica gel materials with improved properties. The materials, such as, for example, fibers, fleeces, powder, monolith and/or coating are employed, for example, in medical technology and/or human medicine, in particular for wound treatment.
1 . A silica sol material comprising at least one therapeutically active ingredient obtainable by
a) conducting a hydrolysis/condensation reaction of one or more Si compounds of the formula (I)
SiX 4 (I)
in which the radicals X are identical or different and denote hydroxyl, hydrogen, halogen, amino, alkoxy, acyloxy, alkylcarbonyl and/or alkoxycarbonyl and are derived from alkyl radicals that are optionally substituted straight-chain, branched or cyclic radicals having 1 to 20 carbon atoms, and can be interrupted by oxygen or sulfur atoms or by amino groups,
with acidic catalysis at an initial pH of 0 to ≦7, optionally in the presence of a water-soluble solvent, for at least 16 h at a temperature of 0° C. to 80° C.,
b) subsequent evaporation a single-phase solution having a viscosity in the range from 0.5 to 2 Pa·s at a shear rate of 10 s −1 at 4° C. is produced,
c) this solution is subsequently cooled and
d) is subjected to a kinetically controlled maturation, a homogeneous sol being formed and in one or more of the steps a) to d) and said at least one therapeutically active ingredient being added thereto.
2 . The silica sol material as claimed in claim 1 , wherein for the acidic catalysis H 2 O acidified with nitric acid is employed in a molar ratio in the range 1:1.7 to 1:1.9, and the hydrolysis/condensation reaction is carried out for at least 16 h, and between 20 and 60° C.
3 . The material as claimed in claim 1 , wherein the hydrolysis/condensation reaction in step a) is carried out at 20 to 60° C., over a period of at least 16 h to 4 weeks.
4 . The material as claimed in claim 1 , wherein the step b) proceeds in a closed apparatus at a reaction temperature of approximately 30 to approximately 90° C.
5 . The material as claimed in claim 1 , wherein the solution in step c) is cooled to 2° C. to 4° C.
6 . The material as claimed in claim 1 , wherein the maturation in step d) takes place at a temperature from 2° C. to 4° C.
7 . The material as claimed in claim 1 , wherein in step d), the maturation is carried out up to a viscosity of the sol of 30 to 100 Pa·s at a shear rate of 10 s −1 at 4° C. and a loss factor of 2 to 5 (at 4° C., 10 s −1 , 1% deformation).
8 . The material as claimed in claim 1 , wherein the Si compound employed in step a) is tetraethoxysilane.
9 . A material as claimed in claim 1 as a material for the production of a biodegradable and/or bioabsorbable silica gel material.
10 . A material as claimed in claim 1 as a spinning material for the production of a biodegradable and/or bioabsorbable fiber and fleece in human medicine and/or medical technology optionally for wound treatment and/or wound healing.
11 . A material as claimed in claim 1 as a material for the production of a bioabsorbable and/or bioactive powder, monolith and/or coating.
12 . A bioabsorbable and/or bioactive powder, monolith and/or coating, which is prepared by at least one further step starting from the silica sol material as claimed in claim 1 .
13 . A biodegradable and/or bioabsorbable fiber material, wherein a silica sol as claimed in claim 1 is subsequently spun in a spinning process.
14 . The biodegradable and/or bioabsorbable fiber material as claimed in claim 13 , wherein the fiber material comprises fibers, endless filaments, fleeces and/or fabric.
15 . A process for the production of a silica sol material spinnable to at least 70% of the total reaction batch, by
a) an at least 16-hour hydrolysis/condensation reaction of one or more
Si compounds of the formula (I)
SiX4 (I)
in which the radicals X are identical or different and denote hydroxyl, hydrogen, halogen, amino, alkoxy, acyloxy, alkylcarbonyl and/or alkoxycarbonyl and are derived from alkyl radicals that are optionally substituted straight-chain, branched or cyclic radicals having 1 to 20 carbon atoms, and can be interrupted by oxygen or sulfur atoms or by amino groups,
b) evaporation for the production of a single-phase solution optionally with a simultaneous gentle mixing of the reaction system,
c) cooling of the single-phase solution and
d) kinetically controlled maturation for the production of the silica sol material.
16 . A process for the in-vitro multiplication of cells, comprising using a fiber matrix of fibers as claimed in claim 13 serving as a cell support substance and/or guide structure for an extracellular matrix formed by the cells.
17 . A cell conglomerate, tissue and/or organs, which can be produced according to the process as claimed in claim 16 .
18 . A cell conglomerate, tissue and/or organs having a fiber matrix of polysilicic acid, the biodegradable and/or bioabsorbable fiber matrix after a period of time of 4 weeks after in-vitro cell population for the first time being at least 60% identical with the original 2- or 3-dimensional shape of the fiber matrix.