US 3656906 A
A method for detecting and quantitating submicrogram quantities of cannabinoids and their analogs in biological materials including blood plasma and urine. Detection system is based on the condensation of the cannabinoids with a polycarboxylic acid to give a highly fluorescent derivative, the intensity of the fluorescence being maximized in the pH range of 9-11.
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Description (OCR text may contain errors)
llnited States Patent ullock  Apr. 18, W72
54] METHOD FOR DETECTING AND 260/247.7 E, 293.57, 293.58, 326.5 B, 327 TH, QUANTITATING THE P SE OF 332.3, 340.9, 343.2 R, 345.3, 479 R, 520, 619 CANNABINOIDS AND ANALOGS THEREOF IN BIOLOGICAL  MATERIALS AND RESULTING OTHER PUBLICATIONS PRODUCTS Francis J. Bullock, Acton, Mass.
Assignee: Arthur D. Little, Inc., Cambridge, Mass.
Filed: Apr. 13, 1970 Appl. No.: 28,015
US. Cl. ..23/230 B, 260/247.l, 260/247.5 B, 260/247.7 E, 260/293.57, 260/293.58, 260/326.5 B, 260/327 TH, 260/332.3, 260/340.9, 260/343.2 R, 260/345.3, 260/479 R, 260/520, 260/619 Int. Cl. ..G01n 31/22 Field of Search ..23/230 B, 230; 260/247.l, 247.5 B,
lrudayasamy, A. et al., Chem. Abstr. 71, 1969 Primary Examiner-Morris O. Wolk Assistant Examiner-J1. M. Reese Attorney-Bessie A. Lepper [5 7] ABSTRACT A method for detecting and quantitating submicrogram quantities of cannabinoids and their analogs in biological materials including blood plasma and urine. Detection system is based on the condensation of the cannabinoids with a polycarboxylic acid to give a highly fluorescent derivative, the intensity of the fluorescence being maximized in the pH range of 9-1 1.
3 Claims, No Drawings biological materials including blood plasma and urine and to the novel compounds. rise to the test.
There is a need for a qualitative and quantitative test for. detecting the presence of marihuana and of related compounds prod uced'in the reactionswhich gives and derivatives of'marihuana in blood plasma and urine to determine whether or not an individual has consumed one of the marihuana related drugs in one form or another. Such a test must be reliable and relatively easy to perform.
It is therefore a primary object of this invention to provide a method of detecting and quantitating cannabinoids and particularly of detecting and quantitating these compounds in biological materials. It is another object to provide a method of the character described whichis reliable and relatively simple to perform. It is another primary object of this invention to provide novel compounds which are derivatives of cannabinoids. Other objects of the invention will in part by obvious and will in part be apparent hereinafter.
The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the composition of matter possessing the characteristics, properties, and the relation of constituents which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.
The term cannabinoid is used hereinafter to designate compounds with a cannabinoid structure and their analogs and it includes those compounds which may be represented generally by formula l or formula H" where R is hydrogen or lower-alkyl and n is 0, l, 2, or 3, m is where Ibis hydrogen, alkyl, cycloalkyl-lower -alkyl, lower-alkanoyl, cycloalkyl-lower-alkanoyl,lower-alkenyl, lower-alkynyl, halo-lower-alkenyl, phenyl-lower-alkyl, phenylylower-alkenyl, phenyl-lower alkynyl, (the benzene ring of the phenyl being substituted by l to 3 members of lower-alkyl, lower-alkoxy, 7 halo, nitro, lower-alkyl-mercapto, methylenedioxy, trifluoromethyl) and m is l or 2, n is l or. 2 and m n is 2 or 3; and wherein formula II R is alkyl containing from one to 10 carbon atoms, R, is hydrogen or lower-alkanoyl, R is 1-(2-isopropyl-5-lower-alkyl-l-cyclobexenyl) having theformula 5 CH3 CH where R is lower-alkyl; 3-(l-R -4-isopropyl-l,2,5,6-
tetrahydropyridyl) having the formula l io N where R is hydrogen, lower-alkyl, or phenyl-lower-alkyl; 4- (l-R -3-isopropyl-l,2,5,6-tetrahydropyridyl) having the formula H CH; \CH; where R has the meaning given above; or 3-(2-isopropyl- 1 ,4- ethanol ,4,5,6-tetrahydropyridyl) having the formula As used herein, the term lower-alkyl" means saturated, monovalent aliphatic-radicals, including straight and branched-chain radicals of from one to six carbon atoms, as illustrated by, but not limited to methyl, ethyl, propyl, isopropyl, butyl, sec.- butyl, amyl, hexyl, and the like.
As used herein, the term alkyl means saturated, monovalent aliphatic radicals, including straight and branched-chain radicals of from one to 20 carbon atoms, as illustrated by, but not limited to methyl, n-amyl, n-hexyl, 2-heptyl, n-heptyl, 3-methyl-2-octyl, n-octyl, 2-nonyl, Z-tetradecyl, nhexadecyl, 2-eicosanyl, and the like.
As used herein, the term lower-alkenyl" means monovalent, aliphatic-radicals of from three to seven carbon atoms which contain at least one double bond, and are either straight or branched-chain, as illustrated by, but not limited to l-( 2-propenyl), 1-( 3-methyl-2-propenyl l-( l ,3-dimethyl-2- propenyl), 1-( 2-hexenyl), and the like.
i As used herein, the term lower-alkynyl" means monovalent, aliphatic-radicals, of from three to seven carbon atoms which contain at least one triple bond, and are either straight or branched, as illustrated by, but not limited to 1-(2- propynyl, l-(l-methyl-2-propynyl), l-(2-heptynyl), and the like.
one to six carbon atoms, as illustrated by, but not limited to formyl, acetyl, propionyl, a-methylpropionyl, butyryl, hexanoyl, and the like.
As used herein, the terms phenyl-lower-alkyl," phenyllower-alkenyl, and phenyl-lower-alkynyl means a monovalent radical consisting of a phenyl nucleus bonded to the rest of the molecule, respectively, through a divalent lower-alkylene radical of from one to four carbon atoms as illustrated by, but not limited to methylene, l,l-ethylene, 1,2- ethylene, l,3-propylene, l,2-propylene, l,4-butylene, and the like, or through a divalent lower-alkenylene radical of from two to four carbon atoms, as illustrated by, but not limited to l,2-ethenylene, l,3-( l-propenylene), 1,3-(l-butenylene), 1,4- (Z-butenylene), and the like, or through a divalent lower-alkynylene radical of from two to four carbon atoms, as illustrated by, but not limited to 1,2-ethynylene, 1,3-propynylene, l,3-( l-butynylene), and the like. Here and elsewhere throughout this specification, it will be understood the benzene ring of phenyl can bear any number and kind of substituents such as would occur to the man skilled in organic chemistry, Solely for illustration, and without limitation, such substituents include lower-alkyl, lower-alkoxy, halo (chloro, bromo, iodo, or fluoro), nitro, lower-alkylmercapto, and the like.
Exemplary of cannabinoids of formula I wherein X is S are CH; CH-( JH-CsHn III l,2-dihydro-4,4-dimethyl-9-hydroxy-7-(1,2-dimethy|heptyl)- 4H-thieno-[2,3-c] [llbenzopyram 5,5 -dimethyll 0-hydroxy-8-( l ,Z-dimethylheptyl 1 ,2,4,5- tetrahydro-4H,SH-thiopyrano [3,4-c] [l]benzopyran.
Cannabinoids of the type illustrated by compounds III, IV and V are the subject of [1.5. Pat. application, Ser. No.
852,928 filed Aug. 25, 1969, in the names of Raj K. Razdan and Harry G. Pars and assigned to the same assignee as the present application. Exemplary of cannabinoids of formula I wherein X is I H: N E BH g- 5 ,5 -dimethyll ,4-ethano- 1 0-hydroxy-8 1( l,2-dimethylheptyl)- l,2,3,4-tetrahydro-5H-[ l ]benzopyrano[-c]pyridine.
Cannabinoids of the type illustrated by compound VI are the subject of US. Pat. No. 3,493,579.
Exemplary of cannabinoids of formula I wherein X is R is hydrogen or lower alkyl are l-hydroxy-3-pentyl-6a,7, l0, 1 Oa-tetrahydro-6,6,9trimethyl- 6H-dibenzo[b,d]pyran (VIII) and l-hdyroxy-3-pentyl-6 a,7,8,l0a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran (IX).
Compounds V1 and VII are well known as components of the active ingredients of marihuana and compounds Vlll and IX are the well known A and A tetrahydrocannabinols, respectively.
Exemplary of cannabinoids of formula I where X is andR is hydrogen or lower alkyl are OH OH CeHu \ (ointment) CaHu 0 3-(Z-dimethylaminoethyD-1 hydroxy-6,6-dihexyI-9-methyl- 7,8,9,10-tetrahydro-6H-dibenzo[b,d]pyran (X) or 3-(2- dimethylaminoethyI)-I-hydroxy-6,6,9-trimethyl- 7 ,8,9, l 0,1 1,12-hexahydro-6I-I-dibenzo[b,d]pyran (XI);
XII and 4,4-dimethyl-9-hydroxy-7-( l ,2-dimethylheptyl)- 1 ,2,3,4- tetrahydrocyclopenta[c][ l]benzopyran (XII) or 4,4-di-( lhexyl)-9-hydroxy-7-( I ,2-dimethylheptyl)-1,2,3,4,l2,13-hexahydrocyclopenta [c][ l ]benzopyran (XIII).
Cannabinoids of the type illustrated by compounds X and XI are the subject of U.S. Pat. application, Ser. No. L550, filed Jan. 8. I970, in the names of Harry G. Pars and Felix E. Grzmchelli; and those ofthe type illustrated by compounds XII and XIII are the subject of U.S. Pat. application Ser. No. (142.192, filed May 2, I967. in the names of Raj K. Razdan, Felix E. Granchelli and Harry G. Pars. Both of these applications are assigned to the same assignee as the present application.
Exemplary of cannabinoids of formula I wherein X is are 10-hydroxy-Z,5,5,8-tetramethyl-l ,2,3,4-tetrahydro-I-I-[ llbenzo-pyranol3,4-d]pyridine (XIV) or I0-hydroxy-2,5,5,8- tetramethyl- 1 ,2,3,4, 1 3,I4-hexahydro-5H-[ I benzopyranol3,4-d]pyridine (XV);
-N CH3 OH CH-H-CsH C O and l0-hydroxy81( l ,2-dimethylheptyl)-3,5,5-trimethyl- 1 ,2,3,4- tetrahydro-5I-I-benzopyrane[3,4-c]pyridine (XVI) or hydroxy-8( l ,2-dimethylheptyl )-3 ,5 ,5-trimethyl 1,2,3 ,4, I 3 l 4- hexahydro-5H-[ I ]benzopyrano[ 3,4-clpyridine (XVII); and
2-benzyl-4-dimethyI-9-hydroxy-7-( 1,2-dimethylheptyl I ,2,3,4-tetrahydro[ l lbenzopyranoI 3,4-c1pyrrole (XVIII) or 2-benzyl-4-dimethyl-9-hydroxy-7-( I ,Z-dimethylheptyl l,2,3,4,l l,l2-hexahydro[ I lbenzopyranol 3,4-clpyrr0le IX).
Cannabinoids of the type illustrated by compounds XIV and XV are disclosed in US. Pat. No. 3,429,889; cannabinoids of the type illustrated by compounds XVI and XVII are the subject of U.S. Pat. application Ser. No. 642,223, filed May 29, 1967, in the names of Harry G. Pars, Felix E. Granchelli and Raj K. Razdan; and cannabinoids, of the type. illustrated by compounds XVIII and XIX are the subject of U.S. Pat. application, Ser. No. 842,690, filed July 17, I969, in the names of Harry G. Pars and Raj K. Razdan. These two applications are assigned to the same assignee as the present application.
Exemplary of the cannabinoids of formula I] wherein R, is hydrogen and R is I-(2-isopropyl-S-Iower-alkyl-l-cyclohexenyl)is EH: OH- H-CsHn CH O a I i 2-[ 1-( 2-isopropyl-5-methyll -cyclohexenyl) dimethylheptyl)resorcinol.
Exemplary of the cannabinoids of formula II wherein R is hydrogen and R is 3-( l-R -4-isopropyl-l,2,5,6- tetrahydropyridyl) is I o A N I H CH-CHCsHn O C 3 I H3 XXI H 2-[ 3-( l-benzyl-4-isopropyll ,2,5 ,G-tetrahydropyridyl ]-5-( l ,2-dimethylheptyl)resorcinol.
Exemplary of the cannabinoids of formula II wherein R, is
2-[4-( l-benzyl-3-isopropyll ,2,5,6-tetrahydropyridyl)]-5- methylresorcinol.
Exemplary of the cannabinoids of formula II wherein R is hydrogen and R is 3-(2-isopropyl-l,4-ethano-l,4,5,6- tetrahydropyridyl) is -CII; CH3
wherein R,, R and X have the same meanings as in the compounds of formula I and RR; and R have the same meanings as in the compounds of formula II.
The invention sought to be patented in another of its composition aspects resides in the concept of a class of compounds represented by formulas XXVI and XXVII X will [x1 OH 00, 2 (30, 2 z) 2)m (|)H X V I wherein R R and X have the same meanings as in the compounds of formula I; R R and R have the same meanings as in the compounds of formula II; and Z is a cation such as H*, Na, K and the like.
The invention sought to be patented in one method aspect resides in reacting a cannabinoid of the class defined by formulas I and II with a poycarboxylic acid of the general formula XXVIII HOOC-CH -R -COOH, wherein R is CH XXVIII -omt lontoozrr or rro=ooozn to produce the compounds of the general formulas XXIV and XXV by the following reaction 032). OR I o OOH OII XXV
The invention sought to be patented in another method aspect resides in converting the compounds of of formulas XXIV and XXV to those of formulas XXVI and XXVII by the addition of an alkali to raise the pH to at least 9. The formation of compounds of the formulas XXVI and XXVII gives rise to a high degree of fluorescence emmission at 470 nm when excited at 380 nm. The occurrence of this fluorescence is indicative of the presence of a cannabinoid structure and hence serves as the basis for the detection of marihuana and marihuana derivatives as well as the cannabinoids and their analogs as represented by general formulas I and II.
The cannabinoids in amounts from 0.6 micrograms and greater have been detected by the methodof this invention.
In reacting the cannabinoid with the polycarboxylic acid the hydrogen ion is furnished by an acid catalyst such as polyphosphoric acid, sulfuric acid or a mixture of sulfuric acid and acetic acid. The reaction is preferably carried out at somewhat elevated temperatures, typically in the range from about to C. and for at least 20 minutes.
The polycarboxylic acids of formula XXVIII are illustrated by malic acid, citric acid, isocitric acid, aconitic acid and succinic acid.
The composition and method aspects of this invention are illustrated by the following examples which are meant to be illustrative and not limiting.
' hydroxy-3-pentyl-6a,7,8, l Oa-tetrahydro-6,6,9-trimethyl-6H dibenzo[b,d]pyran) was prepared by the following procedure.
A concentrated solution of the A THC (prepared according to the procedure disclosed by D. Petrzilka, W. Haefliger and C.. Sikemeier in Helvetica Chemica Acta, 52: 1102 (1969)) was made by dissolving 1v milligramof the A THC in l milliliter of absolute ethanol. To 0.2. milliliters of this solution was then added 20 milliliters of human blood plasma. This blood plasma. containing the THC was then diluted with additional fresh plasma to the desired concentrationwhich in the following examples was 0.3 micrograms or more of THC/milliliter of plasma.
Two milliliters of the THC-containing plasma (equivalent to 0.6 micrograms of A THC was diluted with an equal volume of pH 5- citrate buffer and the mixture was saturated with sodium chloride. It was then extracted twice with 5-milliliter portions of hexane containing 1.5% ethanol. The combined hexane layers were washed once by shaking with 5 milliliters of 0.1 normal sodium hydroxide solution. The hexane layer was separated and evaporated to dryness in a l-5-milliliter graduated, stoppered conical centrifuge tube. 0.5 milliliter of an ethanolic solution of malic acid (1 mg/ml) was added and the ethanol evaporated by warming the tube in a water bath at 90. The refluxing ethanol was allowed to wash the contents of the tube into the tip. After evaporation of the ethanol, 0.5 ml of a polyphosphoric acid mixture (prepared by mixing polyphosphoric acid and 85% phosphoric acid in a 2:1 volume ratio) was added; the tube was stoppered and heated at 90 for 20 minutes. The mixture was diluted with 1 milliliter of distilled water and extracted with 10 milliliters of hexane. The hexane layer was washed once by shaking with 5 milliliters of pH 5 citrate buffer. The aqueous layer was removed and there remained in the hexane layer the product l-hydroxy-B-pentyl- 6a,7 ,8, l a-tetrahydro-6,6,9-trimethyl-6-H-dibenzo[ b,d]p yran-Z-acrylic acid 8-lactone of the formula The formula for the resulting lactone-is written in this manner since at least a part, if not all, of the'A THC is probably converted to the A THC along with the formation of the rS-lactone in the polyphosphoric acid at 90 C.
EXAMPLE 2 presence of 00o Na H11 on, 0
was indicated by a fluorescenceemission at 470nm which was significantly higher than that obtained by carrying 2 milliliters of control plasma through the procedures of Examples 1 and 2.
The production of the fluorescent acrylate (or the corresponding acrylic acid) is indicative of the presence of the cannabinoid structure as represented by formula I. It will be seen that this method of THC detection was capable of detecting the presence of as little as 0.6 micrograms of the THC.
EXAMPLE 3 l-Hydroxy-3-pentyl-6a,7, l0, IOa-tetrahydro 6,6,9- trimethyl-6H-dibenzo[b,d]pyran-2-acrylic acid ii-lactone The procedure of Example 1 was repeated by substituting a concentrated solution of A THC (l-hydroxy-3-pentyl-6 a,7, l0,10a-tetra-hydro-6,6,9-trimethyl-6H-dibenzo[b,d]p yran) for the A THC Example 1. This resulted in the formation of the compound of the formula l-l-lydroxy-3-pentyl-6a,7,l0,l0a-tetrahydro-6,6,9- trimethyla6H-dibenzo[b,dlpyran-2-sodium Acrylate The product lactone of Example 3 was subjected to the procedure detailed in Example 2. An intense fluorescence at the excitation of 380 nm was noted. The acrylate salt 1 I, ooo Na or of example 2 may easily be converted to the acrylic acid form by reaction with a suitable acid such as hydrochloric acid.
EXAMPLE 5 1-Hydroxy-3-pentyl-6,6,9-trimethyl-6H-dibenzo[b,d ]pyran-2-acrylic Acid fi-lactone 5 micrograms of cannabinol in 5 microliters of ethanol was added to a l5-milliliter conical centrifuge tube with 500 micrograms of malic acid and 0.5 milliliter of ethanol. The solvent was removed by warming at 60 C. and then 0.5 milliliter of the polyphosphoric acid mixture of Example 1 was added. The tube was stoppered and the contents heated at C. for 20 minutes. After the contents were cooled, l milliliter of water was added and the mixture was extracted with 7 milliliter of hexane. The hexane layer was removed and washed with 5 milliliters of pH 5 citrate buffer to form the product having the formula sHu EXAMPLE 6 l-Hydrxy-3-pentyl-6,6,9-trimethyl-6H-dibenzo[b,d ]pyran-2sodium acrylate A 6-milliliter aliquot of the hexane layer of Example treated with the pH 5 citrate buffer was then transferred to a dry centrifuge tube and shaken for 30 minutes with 2 milliliters of pH buffer. The fluorescence of the aqueous phase was recorded (A excitation 380 nm, A emission 470 nm) and was significantly higher than that of a reagent blank carried through the procedures of Example 5 and this example. The intensity of the fluorescence was about one-third that obtained with an equivalent amount of A THC. The acrylate salt formed had the formula EXAMPLE 7 2,4-Dihydr0xy-5-(6-isopropenyl-3-methyl-2-cyclohexenyl)- fi-pentyl-phenylacrylic Acid 2-8-lactone 5 micrograms of cannabidiol in 5 microliters of ethanol was added to a l5-milliliter conical centrifuge tube with 500 micrograms of malic acid in 0.5 milliliter of ethanol. The solvent was removed by warming at 60 C. and then 0.5 milliliter of the polyphosphoric acid mixture of Example 1 was added. The tube was stoppered and the contents were heated at 90 C. for 20 minutes. After the contents were cooled, l milliter of water was added and the mixture was extracted with 7 milliliters of hexane. The hexane layer was removed and washed with 5 milliliters of pH 5 citrate buffer to form the product having the formula EXAMPLE 8 2,4-Dihydroxy-5-(6-isopropenyl-3-methyl-2-cyclohexenyl)- 6-pentyl-phenyl-l-sodium Acrylate A 6-milliliter aliquot of the hexane layer of Example 7 was transferred to a dry centrifuge tube and shaken for 30 minutes with 2 milliliters of pH 10 buffer. The fluorescence of the aqueous phase was recorded (A excitation 380 nm, A emission 470 nm) and was significantly higher than that of a reagent blank carried through the same procedure. The intensity of the fluorescence obtained with the cannabidiol was about 3 times that obtained with A THC and about 10 times that obtained with cannabinol. The intensely fluorescent compound can be represented by the formula 7 CH3 l 000 Na It will be seen from the above description and from the examples that there is here provided a method of identifying the presence of a cannabinoid, and that the novel reactions disclosed may be used as a test for the presence of a cannabinoid, e.g., one or more of the active ingredients of marihuana, in a body fluid. The novel acrylate salts of the cannabinoids as represented by formulas XXVI and XXVll have utility as standards in a test procedure for identifying cannabinoids and the novel 8-lactones of formulas XXIV and XXV have utility as intermediates in the preparation of compounds of the formulas XXVI and XXVIl, respectively.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and, since certain changes may be made in carrying out the above method and in the compositions set forth without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.
l. A method of detecting the presence of a cannabinoid in a body fluid, comprising the steps of treating an extract of a body fluid containing a cannabinoid with a polycarboxylic acid in the presence of an acid catalyst thereby to condense the cannabinoid with said polycarboxylic acid to form a 6-lactone cannabinoid and then converting the 'fi-lactone form to the free acid or salt form which is intensely fluorescent and detecting said fluorescence as indicative of the presence of said cannabinoid.
2. A method in accordance with claim 1 wherein said polycarboxylic acid has the formula HOOC-CHAB R- COOH, wherein R is CH 3. A method in accordance with claim 1 wherein said cannabinoid is represented by the fonnula andm is 2 and n isO;
where R, is hydrogen or lower alkyl and n is 0, l, 2 or 3, m is 0, l,2or3andm+nis20r3;
where R, is hydrogen or lower-alkyl and m is 0,1,2 or 3, n is 0,1,2or3 andm+n is2or 3;
3,656,906 l3 14 where R is hydrogen, alkyl, cycloalkyl-lower-alkyl, lower-alwhere R is hydrogen, lower-alkyl or phenyl-lower-alkyl; 4- kanoyl, cycloalkyl-lower-alkanoyl, lower-alkenyl, lower-alky- (l-R -3-is0propyl-l,2,5,6-tetrahydropyridyl) having the fornyl, halo-lower-alkenyl, phenyl-lower-alkyl, phenyl-lower-almula kenyl, phenyl-lower-alkynyl, (the benzene ring of the phenyl being substituted by l to 3 members of lower-alkyl, lower-al- 5 kox'y, halo, nitro, lower-alkyl-mercapto, methylenedioxy, trifluoromethyl) and m is 1 or 2, n is l or 2 and m n is 2 or 3;
R is alkyl containing from one to 10 carbon atoms; RWN R is hydrogen or lower-alkanoyl; and R, is l-(2-isopropyl-5-lower-alkyl-l-cyclohexenyl) having 10 the formula cm- H R0 0 where R has the meaning given above; or 3-( 2-isopropyll ,4-
OHFH ethano- 1 ,4,5,6-tetrahydropyridyl) having the formula where R is lower-alkyl; 3-(l-R -4-isopropyl-l,2,5,6- tetrahydropyridyl) having the formula V lho N N CH H 7 ILL CH37A3H