摘要:
Hydrogels are described which have delayed swelling properties. A hydrogel is formed by reacting a hydrophilic monomer, a first crosslinker, and a second crosslinker. The first crosslinker defines the volume expansion of the hydrogel in an aqueous environment, and the second crosslinker, which is biodegradable, can modulate the swelling rate of the hydrogel in aqueous solution. In its dry state, the hydrogel (xerogel) is flexible and elastic. It can also be cut with a knife or scissors, or molded or shaped by hand. The ready shapeability of the xerogel by trimming or compression affords a superior hydrogel for medical applications.
摘要:
Hydrotropic polymer micelles effective for increasing the water solubility of poorly soluble drugs are described. Such hydrotropic polymer micelles have the combined properties of polymer micelles and hydrotropic agents, which display a synergistic effect for increasing the solubility of such drugs. Hydrotropic polymer micelles are formed in solution from amphiphilic copolymers that comprise a hydrophilic polymer and a hydrophobic polymer having pendant hydrotropic agents. A preferred copolymer is a di-, tri- or multi-block copolymer composed of hydrophilic and hydrophobic polymer chains. A particularly preferred hydrophilic chain comprises polyethyleneoxide (PEG) and a preferred hydrophobic chain comprises hydrotropic monomer units derived from nicotinamide. The micelles are found to be much more effective in solubilizing poorly soluble drugs and exhibit an excellent long-term stability even at high loading of drugs. A hydrotropic polymer micelle has nanometer scale size, by which they can deliver poorly soluble drugs to the body through diverse routes of administration.
摘要:
An expandable medical device has elongated struts joined together to form a substantially cylindrical device which is expandable from a cylinder having a first diameter to a cylinder having a second diameter. At least one of the struts includes at least one opening extending at least partially through a thickness of the strut. A beneficial agent is loaded into the opening within the strut in layers to achieve desired temporal release kinetics of the agent. Alternatively, the beneficial agent is loaded in a shape which is configured to achieve the desired agent delivery profile. A wide variety of delivery profiles can be achieved including zero order, pulsatile, increasing, decrease, sinusoidal, and other delivery profiles.
摘要:
Discrete microstructures of predefined size and shape are prepared using sol-gel phase-reversible hydrogel templates. An aqueous solution of hydrogel-forming material is covered onto a microfabricated silicon wafer master template having predefined microfeatures, such as pillars. A hydrogel template is formed, usually by lowering the temperature, and the formed hydrogel template is peeled away from the silicon master template. The wells of predefined size and shape on the hydrogel template are filled with a solution or a paste of a water-insoluble polymer, and the solvent is removed to form solid structures. The formed microstructures are released from the hydrogel template by simply melting the hydrogel template in water. The microstructures are collected by centrifugation. The microstructures fabricated by this method exhibit pre-defined size and shape that exactly correspond to the microwells of the hydrogel template. The method of preparing microstructures based on hydrogel templates is simple and can easily produce large quantities of the microstructures.
摘要:
A superporous hydrogel composite is formed by polymerizing one or more ethylenically-unsaturated monomers, and a multiolefinic crosslinking agent, in the presence of particles of a disintegrant and a blowing agent. The disintegrant, which rapidly absorbs water, serves to greatly increase the mechanical strength of the superporous hydrogel and significantly shorten the time required to absorb water and swell. Superporous hydrogel composites prepared by this method have an average pore size in the range of 10 &mgr;m to 3,000 &mgr;m. Preferred particles of disintegrant include natural and synthetic charged polymers, such as crosslinked sodium carboxymethylcellulose, crosslinked sodium starch glycolate, and crosslinked polyvinylpyrrolidone. The blowing agent is preferably a compound that releases gas bubbles upon acidification, such as NaHCO3. Improved hydrogel composites formed without a blowing agent are also provided.
摘要:
A vaccine composition including an antigen dispersed in an alginate gel is described. The alginate gel is preferably in the form of discrete particles coated with a polymer. Vaccination of vertebrate species can be accomplished by administering the alginate-based vaccine compositions orally.
摘要:
The implantable medical devices are configured to release at least one therapeutic agent from a matrix affixed to the implantable body with a release profile which is programmable to the agent and treatment. The matrix is formed such that the concentration of the therapeutic agent in the matrix varies as a gradient relative to a surface of the implantable body. The change in the concentration gradient of the agent in the matrix directly controls the rate of elution of the agent from the matrix. The therapeutic agent matrix can be disposed in the stent or on surfaces of the stent in various configurations, including within volumes defined by the stent, such as openings, holes, or concave surfaces, as a reservoir of agent, and alternatively as a coating on all or a portion of the surfaces of the stent structure.
摘要:
The present invention relates to method and apparatus for dispensing a beneficial agent into an expandable medical device. The method includes the step of placing an expandable medical device on a mandrel, the medical device forming a cylindrical device having a plurality of openings and dispensing a beneficial agent into the plurality of openings.
摘要:
A fast-melting pharmaceutical tablet comprises a porous, plastic substance, a water penetration enhancer and a binder. One or more drugs can be incorporated into the formulation at different stages of the process so as to afford a pharmaceutically active tablet. Methods of making the pharmaceutical tablet entail combining the porous, plastic material, the water penetration enhancing agent, and the binder so as to form highly plastic granules, which are compressed into tablets. The resulting tablets dissolve rapidly in the mouth and have good hardness with low brittleness. The tablets are particularly valuable to those who have difficulty swallowing conventional pills.
摘要:
The present invention relates to method and apparatus for dispensing a beneficial agent into an expandable medical device. The method includes the step of placing an expandable medical device on a mandrel, the medical device forming a cylindrical device having a plurality of openings and dispensing a beneficial agent into the plurality of openings.