Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Reexamination Certificate
2000-10-25
2003-07-08
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
C424S426000, C424S435000, C424S484000, C424S485000, C424S486000, C424S489000, C424S501000, C424S502000
Reexamination Certificate
active
06589562
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to bioadhesive controlled release systems useful for targeted delivery of biologically active ingredients, such as anti-septic or antibacterial materials, anti-inflammatory, and other active ingredients that interdict the attachment, propagation, growth and or colonization of bacteria on teeth or sensory markers such as flavors and cooling agents to biological surfaces comprising the oral cavity and mucous membranes of various tissues, as well as the release of these active ingredients or sensory markers over an extended period of time. More specifically, the invention pertains to biodegradable bioadhesive and mucoadhesive nano-particles encapsulated within a moisture sensitive microparticle for oral hygiene products such as toothpaste or mouthwash, that sustain the release of biological active ingredients for treatment and prevention of periodontal disease or the release of sensory markers that provide extended sensation of freshness and malodor coverage over an extended period of time.
2. Description of the Related Art
Decreasing the amount of bacteria in the mouth has long been the target of personnel working in the health care field. The oral care industry and health research communities have searched for many years for a way to interdict the attachment, propagation, growth and or colonization of bacteria on teeth since adherence of bacteria is the start of a pernicious chain of events leading to the formation of home care-resistant plaque, calculus, and ultimately, tooth-loss. As the life expectancy of people in developing countries has increased, dental care plays a larger role in overall health, and developing countries are becoming more aware of the importance of oral hygiene. Considering the prevalence of periodontal disease, there is an ongoing need for improved, more effective agents, as well as technology, that inhibit plaque growth to maximize the reduction of oral decay and disease associated with plaque formation.
Periodontal disease, also known as pyorrhea or gum disease, is a major cause of tooth loss in adults. Tooth loss from periodontal disease is a significant problem beginning at about age 35, or even younger. It is estimated that about 4 out of 5 persons already have gingivitis and 4 out of 10 have periodontitis. 75% of the US population suffers from periodontal disease and this epidemic costs billions of dollars a year. The greatest single cause of periodontal disease is poor hygiene, indicated by the appearance of bacterial plaque and tartar (calcified plaque). It is believed that plaque and tartar are more sinister when they occur below the gum line than when they occur at or above the gum line.
Several approaches to fight periodontal disease have been described in patents and in literature. One of the approaches uses liposomes to deliver biologically active ingredients to the oral cavity. Several reports of liposome suspensions containing bioadhesive polymers have been published. The problems with using liposomes and structured vesicles as delivery devices are that these types of systems are unstable and can only be used for encapsulation of certain types of materials. Stability has become the major problem limiting the use of liposomes for controlled delivery, both in terms of shelf life and after administration. Liposomes and vesicles do not remain intact or available in vivo for more than a few hours to a couple of days.
U.S. Pat. No. 5,989,535 discloses a polymeric controlled release composition specifically targeted to the organs that contain mucus membranes at the interface. The invention discloses a polymeric bioadhesive composition that delivers drugs to the target tissue in a sustained manner. The bioadhesive polymer is a water dispersible high molecular weight crosslinked polyacrylic acid copolymer with free carboxylic acid groups further crosslinked with a combination mono, di and polyvalent metal ions, cationic polymers and surfactants. The type of metal ion and the concentration can be adjusted to get the desired adhesive properties along with several physical properties that are important to the formulation of dosage forms.
U.S. Pat. No. 5,993,846 discloses methods for making oil-in-water emulsions having mucoadhesive properties. The emulsion includes a hydrophobic core, a surfactant, and a mucoadhesive polymer which is a polymer or copolymer of acrylic acid or methacrylic acid, a poly (methyl vinyl ether/maleic anhydride) copolymer, pectin, alginic acid, hyaluronic acid, chitosan, gum tragacanth, karaya gum or carboxymethylcellulose surrounding the hydrophobic core. Emulsions of this invention contain a bioadhesive macromolecule or polymer in an amount sufficient to confer bioadhesive properties. The bioadhesive macromolecule enhances the delivery of biologically active agents on or through the target surface. The bioadhesive macromolecule may be selected from acidic nonnaturally occurring polymers, preferably having at least one acidic group per four repeating or monomeric subunit moieties, such as poly(acrylic)- and/or poly(methacrylic) acid (e.g., Carbopol, Carbomer), poly(methylvinyl ether/maleic anhydride) copolymer, and their mixtures and copolymers; acidic synthetically modified natural polymers, such as carboxymethylcellulose (CMC); neutral synthetically modified natural polymers, such as (hydroxypropyl)methylcellulose; basic amine-bearing polymers such as chitosan; acidic polymers obtainable from natural sources, such as alginic acid, hyaluronic acid, pectin, gum tragacanth, and karaya gum; and neutral nonnaturally occurring polymers, such as polyvinylalcohol; or their mixtures. The ionizable polymers may be present as free acids, bases, or salts, usually in a final concentration of 0.01-0.5% (w/vol).
U.S. Pat. No. 5,077,051 discloses bioadhesive microcapsules which permit the sustained release of active agents such as therapeutic or cosmetic agents into, the oral cavity. The bioadhesive microcapsules capable of sustained release comprise of xanthan gum, locust bean gum, a bulking agent and an active agent. The microcapsules are spray-dried or coated with wax and are prepared by a process which comprises spray drying a solution comprising the active agent xanthan gum, locust bean gum and a bulking agent.
U.S. Pat. No. 5,403,578 discloses a stable tooth and gum dentifrice that includes a non-aqueous carrier containing urea, hydrated silica, fluoride, sodium bicarbonate, pyrophosphate, and a peroxide, one or more of the ingredients being microencapsulated and which in use functions as an aid in preventing periodontal disease by reducing incidents of plaque as well as controlling tartar formation, and also as an aid in preventing dental caries and oral odors; and the method of compounding such improved tooth and gum paste. The microencapsulated peroxide may consist of a blend of 75% by weight of calcium peroxide and 25% by weight of calcium hydroxide. The peroxide constituent is provided with an ethylcellulose coating that consists of 6.5% by weight of the finished product.
U.S. Pat. No. 6,007,795 discloses a method for inhibiting bacteria in the mouth of a patient which includes placing a particle containing a degradable material and an anti-microbial agent in the mouth of the patient. In general, the invention features a method for inhibiting bacteria in the mouth of a patient that includes placing a particle containing a degradable material and an anti-microbial agent into the mouth of a patient. The saliva in the mouth causes the degradable material in the particle to degrade, resulting in the release of the anti-microbial agent in a controlled manner over time. The exterior of the particle is water-stable allowing the particles to be incorporated into, for example, aqueous rinses or pastes without the water in the rinse or paste causing the degradable material to degrade prematurely, prior to use.
WO 93/00076 discloses a drug delivery system of microparticles having a spherical core composed of a biopolymer, preferably a protein such as albumin or
Shefer Adi
Shefer Shmuel David
Mathews, Collins Shepherd & McKay, P.A.
Salvona L.L.C.
Tran S.
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