摘要:
The present invention relates to microcapsules for the oral administration of medicinal and/or nutritional active principles (AP), which are smaller than or equal to 1000 .mu.m in size. These microcapsules consist of particles which are coated with a coating material consisting of a mixture of a film-forming polymer derivative, a hydrophobic plasticizer, a functional agent and a nitrogen-containing polymer. These microcapsules are also characterized by their ability to remain in the small intestine for a long time (at least 5 hours) and to allow, during the residence, release and absorption of the AP. The invention also relates to a process for the production of the said microcapsules.
摘要:
The present invention relates to a modified collagen which is soluble in water and/or in aprotic polar organic solvents and which comprises free or substituted thiol functional groups carried by residues of cysteine or its derivatives, the residues being, at least partially, residues which are directly grafted onto the collagen chain, characterized in that it possesses a level of free or substituted thiol functional groups greater than 0.3, preferably 0.5 mM/g of collagen. The invention also relates to the production of these new collagen derivatives and to their application in the preparation of biomaterials, it being possible for the latter to be used especially in the manufacture of implants, prostheses or the like.
摘要:
The present invention relates to novel organic products resulting, for example, from the condensation of a dicarboxylic acid with a sulfur-containing amino acid or one of its derivatives. These products contain reactive thiol SH functions which can be oxidized to form disulfide bridges, resulting in polymers, which may or may not be crosslinked.These novel organic products correspond to the following formula: ##STR1## The invention also relates to the polymers and/or networks deriving from the products of formula (I) and to one of the methods for obtaining these products and their derivatives.Applications as biomaterials: sutures, ligatures, prostheses, adhesives or systems for the controlled release of active principles.
摘要:
Gelation-resistant, high pot life organopolysiloxane compositions adapted for antiadhesive/release coating applications, are comprised of (1) at least one substantially straight-chain organopolysiloxane having a viscosity ranging from about 50 to 100,000 mPa.s at 25.degree. C. and containing at least x alkenyl unsaturated hydrocarbon groups bonded to a silicon atom, per molecule, wherein x.gtoreq.2, (2) at least one organohydropolysiloxane crosslinking agent having a viscosity ranging from about 10 to 100,000 mPa.s at 25.degree. C. and containing at least y hydrogen atoms bonded to silicon atoms, per molecule, wherein y.gtoreq.2, (3) a catalytically effective amount of a platinum group metal crosslinking catalyst, and (4) an effective amount of at least one azodicarboxylate gelation inhibitor which is inert to the activity of said catalyst (3), but in insufficient amount as to prevent the crosslinking of said polysiloxanes (1) and (2) under crosslinking conditions.
摘要:
The meta-dihalobenzenes are selectively 2-chlorinated by reacting same with a chlorine donor, e.g., hexachlorobenzene or pentachlorobenzene, in the presence of at least one alkali metal amide, e.g., sodamide, and at least one compound which complexes the cation of such at least one alkali metal amide.
摘要:
A process of preparing tris-(ether-amines) of the formula:N--[A--O--(B--O).sub.n --R].sub.3in which R represents a hydrocarbon radical, A and B represent alkanediyl radicals, and n is a whole number between zero and 4, by ammonolysis of an alkylene glycol mono-ether of the formula:HO--A--O--(B--O).sub.n --Rin the presence of 10 to 40 percent by weight of a hydrogenation-dehydrogenation catalyst, based on weight of said alkylene glycol monoether.The tris-(ether-amines) produced, such as tris-(3,6-dioxa-octyl)amine, tris-(3,6,9-trioxaundecyl)amine, tris-(3,6-dioxaheptyl)amine, and tris-(3,6-dioxadecyl)amine.
摘要:
Novel sequestering agents useful for the extraction of metal values and in various organic syntheses comprise a cross-linked organic polymeric substrate, said substrate having covalently coupled thereto a plurality of functional groups, the free valence of which having the structural formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.6 and R.sub.7, which are identical or different, each represents a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms, R.sub.5 and R.sub.8, which are also identical or different, each represents a hydrogen atom, an alkyl or cycloalkyl radical having 1 to 12 carbon atoms, a phenyl radical, a --C.sub.g H.sub.2q --.phi. or C.sub.q H.sub.2+1 --.phi.-- radical, and further wherein q ranges from 1 to about 12, and n, m and p, which are also identical or different, range from 1 to 10, and .phi. is phenyl.
摘要:
The invention provides a novel process for the preparation of glycidyl polyethers of polyphenols. The process comprises reacting at least one alkali metal salt of a polyphenol with at least one 2,3-epoxy-1-haloalkane in an anhydrous and essentially aprotic medium, in the presence of a compound of the formulaN[CHR.sub.1 --CHR.sub.2 --O--(CHR.sub.3 --CHR.sub.4 --O).sub.n --R.sub.5 ]3wherein n is an integer of from 0 to 10 inclusive; R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which can be the same or different, are each a hydrogen atom or an alkyl radical having 1 to 4 carbon atoms; R.sub.5 is a hydrogen atom, an alkyl radical having 1 to 12 carbon atoms, a cycloalkyl radical having 3 to 12 carbon atoms, a phenyl radical, a ##STR1## radical or a ##STR2## radical; and m is an integer from 1 to 12 inclusive. The process is especially useful in the preparation of glycicyl polyethers of bisphenol A.
摘要:
A new industrial product, tris(5-amino-3-thiapentyl)amine, which can be obtained by the action of tris(ethanethiol)amine on aziridine in a molar ratio of aziridine to tris(ethanethiol)amine of between about 3 and 3.5. The new product is useful as intermediate for the production of additives for lubricating oils.
摘要:
New lubricant additive compositions containing at least one alkenyl succinimide of the formula: ##STR1## in which R is an alkenyl group of from about 20 to 200 carbon atoms and m is a whole number from 1 to 3.They are produced from the reaction of an alkenyl succinic anhydride comprising a C.sub.20 -C.sub.200 alkenyl group and tris(5-amino-3-thia-pentyl)amine. The additive compositions are useful in lubricating oils.