Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Biocides; animal or insect repellents or attractants
Reexamination Certificate
1998-09-28
2001-01-09
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Biocides; animal or insect repellents or attractants
C424S400000, C424S406000, C264S013000, C264S014000
Reexamination Certificate
active
06171607
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a unique process and apparatus for making shearform matrix material resulting from transformation of the morphology of feedstock material.
The art of material processing has developed significantly in recent years. In U.S. Pat. No. 4,855,326 various substances having pharmological properties are combined with saccharides and spun to produce a readily water-soluble product. Other disclosures which relate to spinning substances with one or more saccharides are found in U.S. Pat. No. 4,873,085, U.S. Pat. No, 5,034,421, U.S. Pat. No. 4,997,856 and U.S. Pat. No. 5,028,632. U.S. Pat. No. 5,034,421 discloses spun matrix systems containing medicaments having predetermined release patterns.
The examples in the disclosures set forth above describe processing feedstock material by subjecting it to high speed spinning on a spinning head in which the substance is also subjected to heating against a heating element. The change of temperature is quite rapid, which is believed to be occasioned by the spinning head quickly and efficiently spreading the feedstock material against the heating element circumferentially disposed around the perimeter of the spinning head. Thus, extensive surface contact of the feedstock is provided against the heating element itself while being spun.
The feedstock material is heated sufficiently to create an internal flow condition which permits part of the feedstock to move at what is believed to be a subparticle level with respect to the rest of the mass and exit openings provided in the perimeter of the spinning head. The centrifugal force created in the spinning head flings the flowing feedstock material outwardly from the head so that it reforms with a changed structure. The force required to separate and discharge flowable feedstock is only the centrifugal force which results from the spinning head. These examples describe one approach to producing a novel matrix material.
A further reference, U.S. Pat. No. 5,380,473, sets forth a process in which the temperature of a nonsolubilized feedstock carrier is increased to a point where it will undergo internal flow, followed by ejecting a stream of the feedstock and then subjecting it to disruptive fluid shear force which separates it into separate parts or masses which have a transformed morphology. Also disclosed in the ′473 reference is an apparatus with a high pressure nozzle for changing the morphology of the feedstock. The nozzle is directed downwards which has advantages in that material is being expunged therefrom to coincide with the downward pull of gravity. However, it has now been discovered that on a commercial scale a downwardly-directed nozzle must be suspended from a rather large height so that the large quantity of exiting material can fully and completely dry in the air before reaching a bottom collection mechanism. This necessitates extra space and volume in a processing center.
It is an object of the present invention to overcome certain drawbacks which are associated with the above-cited apparatus and procedures. It is also an object of the present invention to provide improvements over the technology previously set forth in the art.
SUMMARY OF THE INVENTION
The present invention is a unique process and apparatus for making a shearform matrix by raising the temperature of a feedstock material which includes a non-solubilized carrier to a point where the carrier undergoes internal flow upon application of an internal fluid shear force. The feedstock is advanced while undergoing internal flow and is then ejected upwardly while in internal flow condition, and subjected to disruptive fluid shear force to form multiple parts or masses which have a morphology different from that of the original feedstock.
The multiple masses are cooled substantially immediately after contact with the fluid shear force and are permitted in accordance with the present invention to fall in a free-flow condition after being propelled upwards, until they are solidified. Accordingly, conditions are provided at the point of shear whereby the feedstock is maintained in a free-flow condition until the new masses are beyond the shearing step. This is preferably accomplished by a steady, yet gentle stream of low pressure air surrounding the nozzle and directed upwards which helps to prevent processed material from falling onto and clogging the nozzle apparatus. Because the material is in a substantially dry form when exiting the nozzle, this low pressure air is sufficient to have the material retain its buoyancy, and free fall away from the apparatus. The low pressure air further serves to remove any remaining moisture as well.
Ideally the temperature of gas is controlled when used as the disruptive shear-producing fluid. In certain embodiments, those skilled in the art will find that the temperature may be controlled to provide a gas temperature which is at least 0.1° C. greater than the flow point temperature of material being ejected for each atmosphere of pressure of gas applied against said material as a shear force. Thus, if there are 10 atmospheres of pressure applied, the temperature of gas should preferably be at least 1° C. greater than the temperature of the material being ejected. This feature has often been found to optimize the shearing effect and maintain the ejected feedstock in free-flow condition until it is separated and has traveled beyond the shear step.
The feedstock material used in the present process is one which includes a carrier selected from the group consisting of saccharide-based materials/thermoplastic polymers, biodegradable polymers and cellulosics. Preferably the feedstock material is organic, that is most compounds of carbon. Basically, the feedstock is selected for use herein based on the ability to be processed without reliance upon dissolution. The feedstock material may contain minor amounts of material which is dissolved, but the processability of the feedstock relies on a carrier capable of undergoing internal flow without the necessity of dissolution. In the case of saccharide-based materials, the feedstock is primarily a solid material which is subjected to the process.
The term saccharide-based materials includes sugars and sugar derivatives. Sugars are referred to in a classical sense which means sucrose, maltose, fructose, lactose, glucose, dextrose, polydextrin, maltose, arabinose, xylose, galactose, et al. Sugar alcohols are also included in the term sugars. A non-limiting list of sugar alcohols includes the following: sorbitol, mannitol, maltitol, pentatol, isomalt (Palatinit®), xylitol, et al. Sugar derivatives include chemical and enzymatic derivatives and includes, but is not limited to, chloro derivatives of sugar such as sucralose.
Saccharide-based materials can have varying degrees of low-monomer saccharides, or sugars, oligomers, and polysaccharides, such as starch. Some saccharide-based materials are prepared by hydrolysis of starch and are classified by the degree of starch polymer hydrolysis. The measuring unit is referred to as D.E. or dextrose equivalent. D.E. is defined as reducing sugars expressed as dextrose and reported as a percentage of the dry substance.
For example, maltodextrins contain a mix of sugars and polysaccharides which range from long-chain oligomers resulting from starch hydrolysis to sugars having a low number of monomeric units. Under FDA guidelines maltodextrin consists of nonsweet, nutritive saccharide polymers having a D.E. of less than 20, while corn syrup solids is regarded by the FDA as having a D.E. greater than 20. The present inventors, however, refer to maltodextrins collectively as saccharide-based material consisting of nonsweet, nutritive saccharide polymers and other oligomers having six-carbon monomer units which collectively provide a carrier material capable of forming a matrix. In all uses, the carrier material in the present invention is nonsolubilized.
In a preferred embodiment of the present invention, other materials can be included in the feedstock. For exa
Bayard Claude
Bogue Beuford A.
Fuisz Richard C.
Mathews Eric H.
Siris Supapong
Fuisz Technologies Ltd.
Levis John F.
McQueeney P. E.
Page Thurman K.
Schmidt Richard D.
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