Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Capsules
Reissue Patent
2000-10-27
2003-02-25
Krass, Frederick (Department: 1614)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Capsules
C424S455000, C424S463000, C424S464000, C424S474000, C424S489000, C424S093200, C424S093200, C424S093200, C426S061000, C426S089000, C426S103000, C426S549000, C426S550000, C426S556000, C426S574000, C426S581000, C426S582000, C426S583000, C426S586000, C426S587000, C426S590000, C426S599000, C426S603000, C426S648000, C426S652000, C426S653000, C426S655000, C426S807000
Reissue Patent
active
RE038009
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention is in the field of pharmacology, and relates to human use of a yellow pigment called zeaxanthin (ZX) in preventing or treating macular degeneration, a disease which damages retinal tissue and causes blindness.
This application is being simultaneously filed with a related patent application entitled, “Method of Making Pure 3R-3′R Stereoisomer of Zeaxanthin for Human Ingestion,” Ser. No. 08/551,166. Both of these two patent applications are assigned to the same assignee (Applied Food Biotechnology, Inc. of O'Fallon, Mo.). The contents of that related application are incorporated herein by reference; upon issuance of a US patent based upon this current application, that related application will be opened for public inspection, if it has not already issued as a US patent.
In addition to describing methods of manufacturing and purifying commercially useful quantities of isomerically pure R-R zeaxanthin, that related patent application contains a fairly extensive discussion of retinal physiology and carotenoid chemistry. Although that Background information will not be repeated herein it its entirety, an overview is provided in the next four paragraphs, to help introduce and explain this invention to those who have not read the other related patent application.
Briefly, there is a yellow region called the macula in the central area of the retina, inside the eyeball. The yellow color is caused by two carotenoid pigments, lutein and zeaxanthin. These carotenoids have a yellow color because they absorb the high-energy radiation of the near-ultraviolet and blue light spectrum and reflect the yellow/yellow-orange wavelengths. It is theorized that since these two pigments absorb wavelengths in the high-energy spectrum, they may help protect retinal cells in the macula against “phototoxic” damage caused by short-wavelength high-energy light radiation.
Lutein and zeaxanthin are chemically very closely related to each other; both have the exact same chemical formulae, differing only in their ring stereochemistry and the spatial placement of one end ring and the placement of a double bond in that end ring, as shown in FIG.
1
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“Macular degeneration” is a medical term that applies to any of several disease syndromes which involve a gradual loss or impairment of eyesight due to cell and tissue degeneration of the yellow macular region in the center of the retina. Age-related macular degeneration (AMD) is the most common form of this type of disease. AMD affects millions of Americans over the age of 60, and is the leading cause of new blindness among the elderly. It is characterized and usually diagnosed by the presence of elevated levels of two types of cellular debris within the retina, called drusen and lipofuscin. These types of cellular debris may accumulate to abnormal levels for a number of reasons, including: (1) retinal cell damage caused by repeated exposure to too much light; (2) inherited genetic factors; (3) poor overall health of an individual; and (4) insufficient quantities of anti-oxidant compounds such as vitamins A, C, and E and selenium in a person's diet. Accumulation of drusen occurs within the capillaries and in the Bruck's membrane, and can impede the transport of oxygen and nutrients to the retinal tissues, and the removal of metabolic wastes from the tissues. Accumulations of lipofuscin occurs within a cellular layer which underlies the photoreceptors and which is responsible for nourishing, replenishing and removing wastes from these highly active visual cells. Accumulation of one or both of these types of debris can disrupt the normal metabolic and cellular processes which must occur in order to maintain retinal and visual health.
Although the presence and the apparent or likely protective role of zeaxanthin in the retina have been recognized for more than a decade, no one has previously been able to create purified zeaxanthin preparations suitable for human consumption, either as drugs for treating macular degeneration, or as vitamin
utritional supplements for reducing the risk of macular degeneration later in life. This has been a major shortcoming, since there are no other effective means for treating or preventing macular degeneration; although &bgr;-carotene, vitamin A, and vitamin E have generally beneficial anti-oxidant effects and may slightly retard the rate of macular degeneration, they do not rise to the level of truly effective treatments. For practical purposes, macular degeneration must be regarded as unpreventable, unstoppable, and irreversible, and anti-oxidants such as &bgr;-carotene, vitamin A, and vitamin E are merely palliative measures that can be used to try to slow down the encroaching damage somewhat, since nothing better is available to the public.
The primary (and previously insurmountable) problems that have been encountered in prior efforts to create purified forms of zeaxanthin for human ingestion include: (1) the extremely high level of chemical similarity between zeaxanthin and other less desirable carotenoids, including lutein and &bgr;-carotene, make it extremely difficult to separate zeaxanthin from lutein and &bgr;-carotene on any commercial scale; and, (2)zeaxanthin itself has three different stereoisomers, called the 3R-3′R isomer (which is desirable, and which is present in retinal cells), the 3S-3′S isomer (which is undesirable and which is not believed to exist naturally in retinal cells) and the S-R meso isomer. The S-R meso isomer is not normally ingested in the human diet, and is not present in human blood, but it is sometimes found in the retina, apparently as a conversion product that is sometimes created when lutein is chemically altered by high-energy light waves. Although hard scientific evidence of its roles and effects in the retina is not yet available, the S-R meso isomer of zeaxanthin is presumably less desirable than the naturally occurring R-R isomer.
It is effectively impossible to separate these three isomers of zeaxanthin from each other in commercial quantities; therefore, synthetic methods of creating racemic (mixed-isomer) mixtures of zeaxanthin are effectively useless in efforts to create zeaxanthin for human ingestion. In addition, although it is theoretically possible to chemically synthesize enriched formulations having reduced quantities of the undesired S-S and S-R isomers, the necessary chemical techniques are extremely difficult and expensive, and have never been commercialized.
That completes an overview of the scientific and medical background of this invention: as mentioned above, these topics are discussed in more detail in the related patent application cited above.
Prior Art Involving Zeaxanthin Synthesis
In analyzing the prior art, it must be recognized that zeaxanthin has been known for more than a decade to be present in the retina, and scientists have hypothesized for at least that long that zeaxanthin appears to play a beneficial protective role in helping prevent phototoxic damage in the retina. However, no one prior to this invention has ever been able to synthesize the purified R-R stereoisomer of zeaxanthin in any quantities sufficient for human consumption. This failure can be attributed to the extraordinary difficulties of (1) separating zeaxanthin from other carotenoids, and (2) isolating the desired R-R isomer of zeaxanthin and removing the undesirable S-S and S-R isomers.
Accordingly, As of October 1995, the only way to purchase zeaxanthin, either in purified form or in a semi-concentrated form in which zeaxanthin comprises more than about 5% of the weight of the preparation, requires the purchase of very small quantities of zeaxanthin (measured in milligrams) from specialty chemical manufacturers such as Atomergic Chemicals Corporation (Farmingdale, N.Y.) or Spectrum Chemical Manufacturing Company (Gardena, Calif.). The 1995 prices of purified zeaxanthin from these specialty manufacturers, in synthetic racemic mixtures that contain large amounts of the undesirable S-S and S-R isomers, ranges from about
Garnett Kevin M.
Gierhart Dennis L.
Guerra-Santos Luis H.
Burnham Daniel
Compton Ronald
Kelly Patrick
Krass Frederick
Zeavision LLC
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