Associative polymer hydrogels
OwnerCarol A. Steinerinventor
Life of this patent
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Abstract
A clear and flexible hydrogel containing hydrophobic microdomains provides for controlled release of medicants or other agents use as a medium for chromatography. These hydrogels are produced by addition of a water insoluble hydrophobic moety containing polymer such as water insoluble hydrophobically modified hydroxyethylcellulose to a surfactant/water or ethanol/water solution where the amount of polymer and the solvent composition are sufficient to produce the hydrogel phase.
Claims11
A clear and flexible hydrogel comprising a water-insoluble hydrophobically modified hydroxyethylcellulose polymer with a molecular weight of at least 50,000 having a degree of hydrophobic substitution of at least 0.8% by weight with hydrophobic moieties having at least 8 carbon atoms, where the hydrogel is formed in a surfactant aqueous solution below the critical micelle concentration of the surfactant or in an ethanol aqueous solution and is characterized by a two phase structure of a swollen aqueous gel phase with stable hydrophobic microdomains dispersed throughout the gel phase which microdomains are composed only of hydrophobic moieties from the polymer and surfactant or ethanol.
A process for producing a swollen gel of a hydrophobically modified cellulose ether in water, characterized in that the process produces clear and flexible hydrogels by the steps of
- (a) preparing solutions of sodium dodecyl sulfate (SDS) and 50,000 to 1,000,000 molecular weight hydrophobically modified hydroxyethylcellulose (HMHEC) with 0.8 to 1.5 weight percent hydrophobic substitution by 8 to 20 carbon atom moieties,
- (b) mixing solutions of SDS and HMHEC to prepare a mixture in the concentration range 1.times.10.sup.-3 M to 8.times.10.sup.-3 M SDS to produce a clear and flexible hydrogel, and
- (c) separating the hydrogel in an amorphous form such that the hydrogel comprises hydrophobic microdomains.
A process for producing a swollen gel of a hydrophobically modified cellulose ether in water, characterized in that the process produces a clear and flexible hydrogel by mixing an ethanol/water solution containing about 44% by weight ethanol with from 0.6 to about 1.4% by weight hydrophobically modified hydroxyethylcellulose (HMHEC) with 0.8 to 1.5 weight percent hydrophobic substitution.
Dependencies are inferred from the claim text.