Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/94—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving narcotics or drugs or pharmaceuticals, neurotransmitters or associated receptors
  • G01N33/946—CNS-stimulants, e.g. cocaine, amphetamines
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C331/00—Derivatives of thiocyanic acid or of isothiocyanic acid
  • C07C331/16—Isothiocyanates
  • C07C331/28—Isothiocyanates having isothiocyanate groups bound to carbon atoms of six-membered aromatic rings
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S436/00—Chemistry: analytical and immunological testing
  • Y10S436/815—Test for named compound or class of compounds
  • Y10S436/816—Alkaloids, amphetamines, and barbiturates

Definitions

• This invention relates to novel tracers and their synthesis and use in an immunoassay for the detection of controlled drugs such as amphetamine (APM), methamphetamine (MAPM) and their derivatives, in a biological or aqueous sample.
• controlled drugs such as amphetamine (APM), methamphetamine (MAPM) and their derivatives
• this invention provides methods for synthesizing novel tracers in which a non- controlled substance is both the starting material in tracer synthesis and the binding site on the resulting novel tracer for the antibody, thereby eliminating the necessity of using controlled substances as starting materials.
• the novel tracers of the present invention can be used as an analyte analog in an immunoassay, such as a continuous flow displacement immunoassay.
• a continuous flow displacement immunoassay works on a principle whereby immobilized antibody is first saturated with a labeled analyte analog, the labeled analyte analog is displaced by the analyte in the testing sample, and the displaced labeled analyte analog is then measured. It was unexpectedly discovered that the novel tracers of the present invention substantially improve the performance of the continuous flow displacement immunoassay as compared with conventionally designed tracers.
• Amphetamine and methamphetamine are derivatives of a compound known as a phenylethylamine. Both amphetamine and methamphetamine are stimulants of the central nervous system and of the sympathetic division of the peripheral nervous system. Like other stimulants, the short-term effects of amphetamine or methamphetamine intake include increased heart rate, increased blood pressure, reduced appetite, dilation of the pupils, feelings of happiness and power, and reduced fatigue. It is because of their stimulant effects that these compounds are abused and sold illicitly.
• Immunoassays have provided preferable alternative methods to using TLC, HPLC and GC/MS assays for the detection and quantitation of amphetamines and methamphetamines.
• immunoassays have improved sensitivity, efficiency and are less labor intensive.
• a number of immunoassay techniques for detecting amphetamines and methamphetamines in urine have been developed. See Brynes, et. al. EPO # 279,213 Bl, Hu et. al., EPO # 371, 422A2, and Heiman et. al., EPO # 371,253 A2 which are incorporated herein by reference as if fully set forth.
• the continuous flow displacement immunoassay has been demonstrated as a useful and rapid method for detecting drugs of abuse in saliva and urine. See Hao Yu et al., Use of the USDT Flow Immunosensor for Quantitation of Benzolecgonine in Urine, Biosensors and Bioelectronics, 725-734 (1996); Nam, D. et al. Programme and Abstracts of TIAFT 2000 at Helsinki, 2000; Liang, G., et al, Proc. of ICADTS 2000, June 22-26, 2000, which are incorporated herein by reference as if fully set forth.
• a tracer as used herein is a labeled antigen or hapten used in an immunoassay to compete with the particular substance of interest (the analyte) for antigen binding sites of an antibody.
• the tracer can be a labeled antigen or hapten identical to the analyte to be detected, or it can be modified in such a way that it is structurally related to the analyte and has the desired cross-reactivity toward the selected antibody.
• a modification to the labeled antigen or hapten that decreases binding affinity may actually enhance the displacement reaction, and consequently the sensitivity of the system.
• most immunoassays generally used the illicit drugs themselves, i.e.
• amphetamines and methamphetamines as tracers to detect the presence and or quantity of these substances in the sample. Because these drugs are illegal, a series of procedural guidelines and paperwork accompanies their utilization in the laboratory. Recent use of non-controlled substances as starting materials in amphetamine and methamphetamine tracer synthesis has been reported (Heiman, D., et al. EP 0 371 233 A2), but the final tracer synthesized still contains the amphetamine molecule itself as the binding site for the anti-amphetamine antibodies.
• the present invention provides methods for the synthesis of a novel set of tracers produced from non-controlled substances yielding a labeled non-controlled substance as the tracer (See Figure 1, Method C).
• the synthesis of these non-drug based tracers does not involve the production of illicit drugs at any point in the synthesis process.
• these novel tracers are ideal for use in immunoassays detecting the presence and/or quantity of amphetamines and methamphetamines in biological or aqueous samples.
• the novel tracers of the present invention are particularly useful in the continuous flow displacement immunoassay.
• This invention relates to novel compositions suitable for use in immunoassays for detecting amphetamine (APM), methamphetamine (MAPM) and their derivatives in biological or aqueous samples.
• the tracer synthesis methods developed in this invention eliminate the use of the illicit drugs, i.e. amphetamine and methamphetamine, as the starting materials for or products of tracer synthesis.
• These non-drug based tracers are particularly useful for the continuous flow displacement immunoassay.
• the present invention describes the processes for synthesizing the novel tracers, and the application of these tracers in fluorescence immunoassays for the detection and quantitation of phenylethylamine derivatives in biological samples.
• Figure 2 depicts the basic structures of amphetamine and methamphetamine.
• Amphetamine and methamphetamine are examples of the analytes that can be detected in the immunoassays of the present invention.
• Amphetamine has an n value of 1.
• the tracers of this invention have the n value of greater than 1.
• the preferred tracers have an n value that is 2 or more.
• Figures 3 and 4 show common fluorescent labels that can be used in the tracer synthesis of this invention.
• the synthetic novel tracer is the compound, labeled l-methyl-3-phenylalkylamine, which is depicted in Figure 5.
• the synthetic novel tracer is the compound N-labeled 1 -methyl-3- ⁇ henylalkylamine, which is depicted in Figure 6.
• the synthetic novel tracer is a compound labeled N-methyl-l-methyl-3-phenylalkylamine, which is depicted in Figure 7.
• the synthetic novel tracer is a compound N-labeled N-methyl- 1-methy 1-3 -phenylalkylamine, which is depicted in Figure 8.
• the synthetic novel tracer is the reaction product of succinidyl active ester of para-hemisuccinito-l-methyl-3- phenylpropylamine-N-trifluoroacetamid with Cy5EDA shown in Figures 9 and 10.
• the preferred tracer is synthesized by the method described in Example II.
• Figure 1 shows methods of tracer preparation.
• Method A involves the use of illicit drugs as starting materials to yield a drug-based tracer.
• Method B involves the use of non-controlled substances to yield a drug-based tracer.
• Method C discloses the method of the present invention of tracer synthesis using non-controlled substances as starting materials and yielding a non-drug-based tracer.
• Figure 2 shows the basic structures of amphetamine and methamphetamine.
• Figures 3 and 4 show common fluorescent labels that can be used in the tracer preparation of this invention.
• Figure 5 depicts the synthetic novel tracer compound N-labeled l-methyl-3- phenylalkylylamine.
• Figure 6 depicts the synthetic novel tracer compound labeled l-methyl-3-
• Figure 7 depicts the synthetic novel tracer compound labeled N-methyl-1-methyl- 3 -phenylalkylamine.
• Figure 8 depicts the synthetic novel tracer compound N-labeled N-methyl-1- methyl-3 -phenylalkylamine.
• Figure 9 depicts the preferred synthetic novel tracer compounds which are the reaction product of succinimidyl active ester of para-hemisuccinito-l-methyl-3- phenylpropylamine-N-trifluoroacetamid labeled with Cy5EDA.
• Figure 10 depicts the preferred synthetic novel tracer compounds which are the reaction product of succinimidyl active ester of para-hemisuccinito-N-methyl-1- methyl 3- phenylpropylamine-N-trifluoroacetamid labeled with Cy5EDA.
• Figure 11 depicts a conventional (drug based) tracer GW5-12.
• Figure 12 is a flow-chart setting forth the general procedures for preparation of p', m' and o'-substituted amphetamine tracers.
• Figure 13 is a flow-chart setting forth the procedure for synthesis of one of the preferred tracers of the present invention.
• Figures 14 and 15 show the comparison of the flow immunoassay of amphetamine with the preferred tracer GW3-38 and the conventional tracer GW5-12.
• compositions and methods for synthesizing compounds for use in fluorescence immunoassays for detecting the presence and or quantity of amphetamine, methamphetamine and their derivatives in biological samples are especially suitable for continuous flow displacement immunoassays.
• An analyte is the substance being tested in an immunoassay.
• the analyte can be amphetamine or methamphetamine.
• An antibody recognizes and is capable of specifically binding to the analyte.
• a tracer is a labeled compound that competes with the analyte for binding to the antibody.
• the present invention uses a tracer that has three parts, namely, a site that binds to an antibody, a linking group, and a label.
• the site on the analyte that binds to the antibody is usually similar to the site on the tracer that binds to the antibody. In other words, if the analyte is amphetamine, the antibody to amphetamine recognizes the same binding site on the tracer that it recognizes on the analyte.
• a typical continuous flow displacement immunoassay involves a solid-phase immobilized antibody to amphetamine or methamphetamine.
• the antigen binding site of the antibody is exposed to a synthetic labeled tracer to form a labeled synthetic tracer- antibody complex.
• the antibody is exposed to tracers such that the antigen binding sites of the antibody are saturated with the labeled synthetic tracers.
• a biological sample suspected of containing the analyte, amphetamine or methamphetamine is continuously flowed past the solid-phase immobilized antibody-labeled synthetic tracer complex. If analyte is present in the sample, the analyte binds to the antibody and displaces the labeled synthetic tracer.
• the success of developing a continuous flow displacement immunoassay based product is based on the selection of antibody and tracer to achieve a fast dissociation rate of the bound tracer from the antibody, thereby permitting a rapid binding of the analyte.
• the ideal continuous flow displacement immunoassay utilizes a system where the antibody has a high affinity for the analyte, and a lower affinity for the tracer. This arrangement where the antibody has a high affinity for the analyte and a lower affinity for the tracer promotes faster displacement.
• the tracers embody the following characteristic: the affinity of the tracer for the antibody is anywhere between 20- 100%. A preferred tracer has about 40-80% cross-reactivity for the antibody.
• the tracer be structurally related to the analyte, amphetamine or methamphetamine. So long as the ligand-binding site of the tracer has 20-100% cross-reactivity with the antibody, it is suitable for use in an immunoassay, especially, the continuous flow displacement immunoassay. Most antibodies to amphetamine and methamphetamine recognize the phenylethylamine derivatives.' The present tracers are useful, so long as the antibodies are capable of recognizing the phenylethylamine analogs. Structural similarity to the analyte is not at issue. This characteristic, the structural dissimilarity between the tracer and the analyte, distinguishes the present tracers from those of prior art.
• Labeling of the tracer may be carried out by means of conventional methods well known in the art.
• the label itself may suitably be a fluorophore, a chromophore, a radiolabel, a metal colloid, an enzyme, or a chemilummescent or bioluminescent molecule.
• Suitable fluorophores and chromophores are disclosed in R.P. Haugland, Molecular Probes, Handbook of Fluorescent Probes and Research Chemicals, 5 th Ed., Molecular Probes, Inc., Eugene, Oreg., 1992, which is incorporated herein by reference.
• fluorophores examples include fluorescein, rodamine, and sulfoindocyanine dye Cy5 (Mujumdar, R.B., et al., Bioconjugate Chemistry, vol. 4, p. 105 (1992).
• the method can be used to detect specific components of biological or aqueous samples, including but not limited to water, blood, plasma, serum, blood or urine.
• Saliva has been demonstrated as a useful test matrix for the detection and measurement of drugs of abuse.
• saliva samples can be detected by GC/MASS up to 2 days after the last dose.
• S. Suzuki, T. Inoue and S. Inayama Analysis of methamphetamine in hair, nail, sweat, and saliva by mass fragmentography, J. Anal. Toxicol. 1989, 13, 176-178.
• Step 1 Preparation of l-methyl-3-phylpropylamine-N-trifluoroacetamide:
• A1C1 3 was added to a mixture of 0.24g succinic anhydride and 0.4g l-methyl-3- 15 phenylpropylamine-N-trifluoroacetamide in 5mL of dichloromethane at room temperature. The resulting mixture was stirred at 0°C for one hour and then left at room temperature overnight. 5ml of 3M aqueous HC1 solution was added to the mixture and the organic layers were extracted with ethyl acetate. The combined organic layers were dried over Na 2 SO , and yielded a crude product of 0.5g. Further purification of the crude product 20 was completed with a silica gel column, eluting with 1 :2 ethyl/hexanes. 0.3g of pure para- hemisuccinito-l-methyl-3-phenylpropylamine-N-trifluoroacetamide was obtained.
• Step 3 Reduction of para-hemisuccinito-l-methyl-3-phenylpropylamine-N- trifluoroacetamide
• Step 5 Coupling of succinimidyl active ester of para-hemisuccinito-l-methyl-3- phenylpropylamine-N-trifluoroacetamide with Cy5EDA
• Flow Immunoassay Instrument which contains the necessary pumps, valves, tubing, exchangeable columns and fluorescence detector for performing a continuous flow displacement immunoassay.
• Amphetamine standards were prepared by adding amphetamine (Sigma Chemicals, St. Louis, MO) at different concentrations into the negative saliva. Chemicals and buffers were obtained from Sigma and Aldrich, Company.
• a micro-polystyrene column with an inner diameter of 2mm and a length of 10mm was filled with 4mg of the prepared resin.
• the filled column was installed into one of the five flow channels of the LifePoint Immunoassay Instrument.
• the column had been pre- washed with an appropriate buffer controlled by an automatic system supported by Labview software (National Instruments, Inc.).
• 50 ⁇ l of the saliva sample was passed through the channel at a flow rate of 100 to 300 ⁇ l/minute.
• the average intensity of the fluorescence signal was used to determine the concentration of amphetamine in the sample.
• Step 1 Preparation of ⁇ -methyl-l-methyl-3-phenylpropylamine- ⁇ - trifluoroacetamide: A solution of 0.4 g of N-methyl-l-methyl-3-phenylpropylamine in 1 ml of acetonitrile was stirred. 1 ml of trifluoroacetic anhydride and 0.6 ml of pyridine was added to the solution at room temperature, and the resulting mixture was stirred overnight at room temperature. Next, the mixture was placed in ice water. The crude product was extracted with ethyl acetate, and the organic layers were combined and dried over Na SO 4 . The desired product was obtained by removal of the organic solvent. TLC analysis ensured that the product was pure enough for the next synthesis step.
• Step 2 Preparation of p'-hemisuccinito-N-methyl-l-methyl-3- ⁇ henylpropylamine- N-trifluoroacetamide
• 0.2g of A1C1 3 was added to a mixture of 0.1 g succinic anhydride and 0.2g N- methyl- l-methyl-3-phenylpropylamine-N-trifluoroacetamide in 5ml of dichloromethane at room temperature. The resulting mixture was stirred at 2°-8°C for 1 hour and then left at room temperature overnight. 2ml of 3M aqueous HC1 solution was added to the mixture, and the product was extracted with ethyl acetate. The organic layers were combined and dried over Na 2 SO 4 . The organic solvent was removed to obtain 0.2g of a crude product. Further purification of the crude product was completed with a silica gel column.
• Step 3 Reduction reaction of para-hemisuccinito-N-methyl-l-methyl-3- phenylpropylamine-N-trifluoroacetamide
• Step 4 Preparation of succinimidyl active ester of para-hemisuccinito-l-methyl-3- phenylpropylamine-N-trifluoroacetamide:
• Step 5 Coupling of succinimidyl active ester of para-hemisuccinito-l-methyl-3- phenylpropylamine-N-fluoroacetamide with Cv5EDA:
• succinimidyl active ester of para-hemisuccinito-l-methyl-3- phenylpropylamine-N-fluoroacetamide was mixed with 2.5mg of CyEDA in 0.5ml of borate buffer pH 9. The solution was stirred at room temperature for 4 hours, and the resulting solution was directly spotted onto a C18 plate and developed with 70/30- methanol/ water. The product band was cut out and the coupled succinimidyl active ester of para-hemisuccinito- 1 -methyl-3 -phenylpropylamine-N-fluoroacetamide with Cy5EDA was extracted with methanol.
• the selected anti-amphetamine antibody (available for example, from Omega
• Biologicals, Inc., Bozeman, MT was coupled to Emphase resin according to the manufacturer's standard procedure and then, saturated with prepared tracers such as GW3- 38, a novel tracer of the present invention (Figure 9) and GW5-12, a conventional tracer ( Figure 11).
• the resulting complex mixture was allowed to proceed at 4°C overnight while roller mixing.
• the complex resin was washed with 0.1M PBS (10% MeOH) until a stable baseline was obtained.
• the washed resin was added to the same volume of 150 mM trehalose buffer in 50 mM PBS (pH 7.4), and freeze dried.

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• 2000
  • 2000-12-04 US US09/730,095 patent/US6472228B2/en not_active Expired - Fee Related
• 2001
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