Controlled release coatings derived from aqueous dispersions of zein
First Claim
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1. A stabilized aqueous dispersion of zein, comprisingan aqueous dispersion comprising from about 0.1 to about 10 percent zein w/v having a particle size from about 0.01 μ
- m to about 10 μ
m, andan amount effective to preserve said dispersion of a pharmaceutically acceptable preservative.
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Abstract
Stable aqueous dispersions of zein which may be used as controlled release coatings of pharmaceutical, animal, health, or food products in an inorganic solvent-free environment are disclosed, as well as methods for preparing the same.
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Citations
34 Claims
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1. A stabilized aqueous dispersion of zein, comprising
an aqueous dispersion comprising from about 0.1 to about 10 percent zein w/v having a particle size from about 0.01 μ - m to about 10 μ
m, andan amount effective to preserve said dispersion of a pharmaceutically acceptable preservative. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- m to about 10 μ
- 10. A method of preparing a stable aqueous dispersion of zein, comprising adding a pharmaceutically acceptable preservative to an aqueous dispersion of zein comprising from about 0.1 to about 10 percent zein w/v having a particle size from about 0.01 microns to about 10 microns.
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15. A method for preparing an aqueous dispersion of zein, comprising
adding zein to a solvent mixture comprising water and from about 60 to about 90 percent of an organic solvent selected from the group consisting of ethanol, acetone,.and mixtures thereof, such that the zein dissolves in the solvent mixture, precipitating the zein as fine particles by pouring said solution of zein as a thin stream into an aqueous phase under continuous stirring, to obtain an aqueous dispersion of zein comprising from about 0.1 to about 10 percent zein w/v, evaporating said organic solvent from the mixture, concentrating the resulting aqueous phase to a zein concentration up to about 10% w/v, and preserving the resulting aqueous dispersion of zein by adding an amount of effective to preserve said dispersion of a pharmaceutically acceptable preservative.
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19. A stabilized aqueous dispersion of zein, comprising
an aqueous dispersion comprising from about 0.1 to about 10 percent zein w/v and having a particle size from about 0.01 μ - m to about 10 μ
m, said aqueous dispersion obtained by precipitating zein by pouring a solution of zein in a solvent comprising water and from about 60 to about 90 percent organic solvent as a thin stream into an aqueous phase under continuous stirring, the organic solvent thereafter being substantially removed and the resulting aqueous phase concentrated, andan amount effective to preserve said dispersion of a pharmaceutically acceptable preservative. - View Dependent Claims (20, 21)
- m to about 10 μ
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22. A solid controlled release formulation, comprising
a substrate comprising an active agent, said substrate coated with a controlled release coating to a weight gain from about 3 to about 15 percent, said controlled release coating comprising (i) an aqueous dispersion of from about 0.1 to about 10 percent zein w/v having a particle size from about 0.01 μ - m to about 10 μ
m, said aqueous dispersion obtained by precipitating zein by pouring a solution of zein in a solvent comprising water and from about 60 to about 90 percent organic solvent as a thin stream into an aqueous phase under continuous stirring, the organic solvent thereafter being substantially removed and the resulting aqueous phase concentrated;(ii) a pharmaceutically acceptable preservative; (iii) a pharmaceutically acceptable plasticizer, the preservative and the plasticizer each being included in an amount necessary to provide a strong, continuous film capable of releasing the active agent at a desired rate when the formulation is exposed to an aqueous solution. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
- m to about 10 μ
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31. A method for preparing a controlled release formulation comprising a substrate coated with an aqueous dispersion of zein, comprising
adding zein to a solvent mixture comprising water and from about 60 to about 90 percent of an organic solvent selected from the group consisting of ethanol, acetone, and mixtures thereof, such that the zein dissolves in the solvent mixture, precipitating the zein as fine particles by pouring said solution of zein as a thin stream into an aqueous phase under continuous stirring, to obtain an aqueous dispersion of zein comprising from about 0.1 to about 10 percent zein w/v, evaporating said organic solvent from the mixture, concentrating the resulting aqueous phase to a zein concentration up to about 10% w/v, adding effective amounts of a pharmaceutically acceptable preservative and a plasticizer, coating a substrate comprising an active agent with a sufficient amount of the preserved, plasticized aqueous dispersion of zein to obtain a predetermined controlled release of said active agent when said coated substrate is exposed to fluid in an environment of use.
Specification