Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving hydrolase
Reexamination Certificate
2000-06-29
2003-09-09
Gitomer, Ralph (Department: 1651)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving hydrolase
C435S007900, C435S026000
Reexamination Certificate
active
06617123
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
As the use of illicit drugs in this country has increased, public concern over the problems associated with its effects has grown into a major concern. This concern has led to workplace drug testing in order to identify, treat, and remove active drug users from the workforce. This trend started in the military, and spread rapidly to law enforcement and any “safety-sensitive” private sector jobs such as airline pilots, truck drivers, and active crew members of public transportation. These initial strides into drug testing in the workplace revealed the obtrusive incursion of drug use and abuse in the daily lives of a significant portion of Americans. Further research indicated the staggering costs to public and private industry in terms of lost productivity, increased health care costs, and human suffering and death due to this scourge of drug abuse. As a result, drug testing has rapidly spread to all areas of the public and private sector. The vast majority of workplace drug testing has taken the form of urine testing, because of ease of collection, low cost, and effective indication of recent drug use. Other forms of testing include analysis of blood, saliva, sweat, and hair.
Gamma-hydroxybutyrate (4-hydroxybutyrate, 4-hydroxybutyric acid, Gamma-hydroxybutyric acid, 4-hydroxybutyric acid sodium salt, GHB) was first used for anesthetic purposes in 1961, because it was unpredictable and caused adverse effects, its use was discontinued. Later, GHB was used by body builders for muscle building and weight control. Presently, the U.S. DEA (Drug Enforcement Agency) is investigating GHB to see if it should be a controlled substance. The U.S. FDA (Food and Drug Administration) list GHB as an unapproved drug except for investigational use in the treatment of narcolepsy. Common names for GHB are Scoop, Georgia Home Boy, Grievous Bodily Harm, Liquid Ecstasy, and Cherry Meth among others. Its precursor GBL (gamma-butyrolactone) is used as a GHB substitute and once ingested rapidly converts to GHB. The pharmacological effects of both GHB and GBL are similar and the range of analgesic effect (euphoria) are similar.
In the 1990's GHB has become a popular drug of abuse on college campuses, bars, and dance clubs and is called the “date rape” drug. The abuse of GHB has enormous sociological and economic impact on our society. A typical “date rape” scenario is as follows: The victim(s), usually women, are in a bar, they drink a beverage that has been laced with GHB by a rapist, the victim then becomes catatonic and is usually agreeable with anyone and everyone around them. They can become unconscious and then of course are susceptible to the rapist desires. Later, the victim(s) wakes up completely disoriented, naked and robbed. This type of horrific tragedy is occurring on a daily basis. The victims of “date rape” are not only exposed to the physical assault of rape and robbery, but to the contraction of diseases such as AIDS and STD's. The damage caused and the consequences of such occurrences are immeasurable.
Accordingly, a need exists for providing an easy and convenient manner by which to make a determination of the presence of GHB in urine, in a beverage, or other biological fluids or liquids. A further need exists for a convenient manner by which such determinations may be made by using rapid analysis manual techniques (such as a dipstick or lateral flow devices) and automated techniques that will advance the art significantly. And, the most important need is for a device that would detect GHB using just a single assay that does not require an extraction process or lactone conversion. This would be a marked advancement in the art and would result in the savings of millions of dollars to the drug testing laboratories required to perform GC (gas chromatography) or GCMS (gas chromatography mass spectrometry) testing for GHB and obviously this savings would be passed on to the end user (the businesses which initially request drug's of abuse assays on perspective and current employees). To explain further, the drug testing laboratory would normally perform GC (gas chromatography) or GCMS (gas chromatography mass spectrometry) assay for GHB. The necessary time to perform these assays is burdensome to the laboratory through cost for tech time, reagents, and turnaround time to mention a few. The alternative to this would be the significant advancement in the art that the present device offers which is the capability to detect GHB without lengthy extraction processes of the current art with a single assay.
2. Description of the Related Art
This invention is in the field of toxicology. More specifically, this invention provides test strips (i.e. dry chemistry dipsticks, or on-site test modules utilizing thin layer chromatography in a lateral flow format, or other similar technology to the test strip) and liquid chemistry reagents for use in the detection of GHB with a single assay in aqueous fluids to include but not limited to urine, saliva, serum, blood, sweat extracts, liquid homogenates of hair and liquids such as beverages, soft drinks, mixed drinks to included alcohol, etc.
It is known that the polarity and small molecular size of the GHB molecule and the lack of detectability of the GHB by UV (ultra violet), chromatographic, and spectrophotometric means complicates detection. GHB is relatively unstable and will form the GHB lactone derivative when heated and under acidic conditions. GHB can cause euphoria at less than 50 ug/mL to marked central depression, sleep, coma and death. Currently, all of the methods to detect GHB use and/or solid-phase extraction, liquid-liquid extraction, silyl-derivatization, then GCMS. These methods mentioned are very time consuming, expensive (costing the laboratories, companies ordering drug testing, and general public millions of dollars per year), and labor intensive. The GC-MS, assay is typically performed to verify the urines that screen positive for drugs of abuse. The GC-MS analysis costs 100 times as much as the initial screen ($100 vs $1). Every additional unnecessary GC-MS performed drives up the overall cost of drug testing.
The novel invention described herein describes a method to determine the presence or absence of GHB and its precursor(s) in urine or other fluids by liquid and dry chemistry test means which has not been taught prior to the present art. It should be noted that GHB is not normally found in urine.
There are no published, taught, or even mentioned methods of the present arts technology to detect GHB or GBL in urine by the present arts techniques.
Again, a thorough search of patents and research revealed no relative art (i.e., prior art) with any correlation to this technology. The art of testing for GHB or GBL in urine or other fluids as previously delineated in the literature describe various techniques including methods for solid-phase extraction, liquid-liquid extraction, silyl-derivatization, then GCMS. No reference, however, has described this new art as delineated here. The previous art will be enumerated here to further illustrate the unique advancement in the field of GHB and GBL detection. It has been acknowledged in the art that random urinary sample matrices are very complex, and consist of many urinary constituents which create strong buffering and interference problems (e.g. cannibal like enzymes such as protease). In addition, disease states will significantly impact the nature of urinary contents. Urine is also the repository of all of the body's waste products including excess parent nutrients, vitamins, drugs, and their metabolites. These waste chemicals vary from person to person and significantly contribute to the individual uniqueness that makes assay design for urinary constituents more difficult than any other body fluid. All of these factors impact an assay's ability to obtain acceptable precision and accuracy. The ability of an assay to analyze a biological liquid such as saliva, therefore, rarely ever translates to an effective ass
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