Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Reexamination Certificate
2000-01-07
2002-12-10
Dees, Jose′ G. (Department: 1616)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
C424S400000, C424S401000, C424S489000, C424S497000, C424S498000, C424S500000, C424S501000, C424S502000, C514S458000, C514S474000, C514S725000, C514S844000, C514S963000, C514S964000, C514S965000
Reexamination Certificate
active
06491953
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the controlled release of an active agent from a composition over an extended time. More particularly, the present invention relates to a composition that exhibits improved controlled release of an active agent, wherein the composition comprises an adsorbent bent polymer, an active agent, and a release retardant.
BACKGROUND OF THE INVENTION
The controlled release of an active agent, such as a drug or cosmetic compound, improves the safety, efficacy, and reliability of a treatment regimen that utilizes the active agent. Conventional dosage forms for delivering an active agent often provide a wide variation in the amount of active agent that is available during treatment. Consequently, the treatment regimen requires multiple doses such that the concentration of active agent is maintained at its minimum effective level. In particular, conventional dosage forms quickly release the active agent, which causes a sharp increase in active agent concentration to a peak, followed by a sharp decline in active agent concentration. This wide swing in active agent concentration provides acceptable results at peak or near peak concentrations, but inadequate treatment at lesser concentrations.
This problem can be overcome by administering a lower dose of an active agent in a conventional delivery system at more frequent intervals. However, individuals find such treatment regimens inconvenient, which leads to eliminating or delaying treatment doses, thereby adversely affecting the efficacy of the treatment.
In contrast, controlled release of an active agent regulates the release rate of the active agent and reduces the frequency of treatment doses, thereby improving compliance with the treatment regimen. Ideally, a controlled release of an active agent provides a predictable amount of the active agent for effective treatment, and controls the rate of active agent release over a predetermined time. The controlled release of an active agent can occur at a constant rate, or at a constant declining rate, at some other specified rate or pattern to achieve an efficacious release of the active agent.
The controlled release of an active agent has several advantages including fewer compliance problems during the treatment regimen, utilizing less of the active agent during treatment, improving efficacy of the treatment, and an overall cost savings. Although such benefits are recognized in the art, it has been difficult to provide compositions that achieve a controlled release of an active agent.
It has been especially difficult to achieve a controlled release of a water-soluble active agent when the water-soluble agent is a component of an aqueous controlled release composition, or when the water-soluble agent, in its controlled release form, is subjected to an aqueous medium. In these situations, the water-soluble agent has a tendency to be released too quickly from the composition.
Conversely, it is difficult to achieve a controlled release of an oil-soluble active agent when the oil-soluble active agent is a component of an oil-based controlled release composition or when the oil-soluble active agent, in its controlled release form, is subjected to a nonaqueous medium. In this situation, the oil-soluble agent has a tendency to be released too quickly from the composition.
In particular, a water-soluble or an oil-soluble active agent can be converted into its controlled release form by adsorbing the active agent onto an adsorbent polymer. The resulting controlled release form of the active compound can be formulated into a solid composition, e.g., a tablet or powder, a semisolid composition, e.g., a cream or gel, or a liquid composition, e.g., an emulsion or dispersion. Prior compositions have demonstrated a premature release of a water-soluble active agent when the controlled release form of the active agent is incorporated into an aqueous medium, like an emulsion, or when a semisolid or solid composition contacts an aqueous medium. Similarly, there is a premature release of an oil-soluble active agent when the controlled release form of the active agent is incorporated into a nonaqueous medium, like a body oil, or when the composition contacts a nonaqueous medium.
The present invention is directed to over-coming the problem of premature release of an active agent from controlled release compositions.
SUMMARY OF THE INVENTION
The present invention is directed to compositions that provide a controlled release of an active agent, including water-soluble and oil-soluble active agents. More particularly, the present invention is directed to a controlled release composition comprising an adsorbent polymer, an active agent, and a release retardant.
Therefore, one aspect of the present invention is to provide a controlled release composition comprising an adsorbent polymer, an active agent that is absorbed onto the adsorbent polymer, and a release retardant that imparts improved controlled release properties to the composition.
Another aspect of the present invention is to provide a controlled release composition comprising (a) an adsorbent polymer, having adsorbed there-to at least an equal weight amount, and typically several times the weight, of the adsorbent polymer of (b) a water-soluble or oil-soluble active agent, and (c) a release retardant that coats and/or is adsorbed onto the adsorbent polymer and active agent.
Yet another aspect of the present invention is to provide a controlled release composition comprising a water-soluble active agent, wherein the composition is in the form of an emulsion and exhibits a controlled release and delivery of the water-soluble agent.
Another aspect of the present invention is to provide a controlled release composition comprising an oil-soluble active agent, wherein the composition is based on a nonaqueous solvent, like an oil, and exhibits controlled release and delivery of the oil-soluble agent.
Another aspect of the present invention is to provide a controlled release composition containing an active ingredient selected from the group consisting of a skin care compound, a topical drug, an antioxidant, a dye, a self-tanning compound, an optical brightener, a deodorant, a fragrance, a sunscreen, a pesticide, a drug, and similar compounds, and mixtures thereof.
These and other aspects and novel features of the present invention will become apparent from the following detailed description of the preferred embodiments.
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Sojka Milan F.
Spindler Ralph
Amcol International Corporation
Dees Jose′ G.
Lamm Marina
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