CBN and D9-THC concentration ratio as an indicator of the age of stored marijuana samples*
Sections
ABSTRACT
Introduction
Experimental basis
Results and discussion
References
Author: S. A. ROSS, M. A. ELSOHLY
Creation Date: 1999/12/01
CBN and D9-THC concentration ratio as an indicator of the age of stored marijuana samples*
S. A. ROSS
National Center for the Development of Natural Products, Research Institute of Pharmaceutical Sciences, Department of Pharmacognosy, School of Pharmacy, University of Mississippi, Oxford, Mississippi, United States of America
M. A. ELSOHLY
National Center for the Development of Natural Products, Research Institute of Pharmaceutical Sciences, Department of Pharmaceutics, School of Pharmacy, University of Mississippi, Oxford, Mississippi, United States of America
ABSTRACT
The concentration of D9-tetrahydrocannabinol (THC) and cannabinol (CBN) in cannabis plant material (marijuana) of different varieties stored at room temperature (20-22o Celsius (C)) over a four-year period was determined. The percentage loss of THC was proportional to the storage time. On average, the concentration of THC in the plant material decreased by 16.6% ±7.4 of its original value after one year and 26.8% ±7.3, 34.5% ±7.6 and 41.4% ±6.5 after two, three and four years, respectively. A relationship between the concentration ratio of CBN to THC and the storage time was developed and could serve as a guide in determining the approximate age of a given marijuana sample stored at room temperature.
Introduction
The stability of (-)-D9-tetrahydrocannabinol (D9-THC) has been the subject of several investigations (1-13). In 1970, Liskow (1) reported that marijuana deteriorates during storage at room temperature because of the loss of D9-THC at a rate of 3 to 5 per cent a month. Shoyama and others (3) were able to isolate cannabinolic acid (CBNA) from stored hemp but not from fresh hemp, and concluded that conversion of tetrahydrocannabinolic acid (THCA) to CBNA was effected by ultraviolet light and by storage and heat. The same conclusion was reached by Turner and others (4, 5), who reported that THC disappeared at a rate of 3.83, 5.38 and 6.92 per cent per year over two years when stored at -18o, 4o, and 22o C, respectively. The loss of THC was essentially complete at 37o C and 50o C. Fairbairn and others (6) reported that carefully prepared herbal or resin cannabis products are reasonably stable for one to two years if stored in the dark at room temperature.
Razdan and others (2) found thatD9-THC is much less stable than D8-THC and is converted mainly to CBN. The degradation of D9-THC to CBN in the plant material on storage was also proposed by Waller and others (7), Razdan and others (8), El-Kheir and others (9), Hanus and others (10) and Yotoriyana and others (11). Although CBN is the major observed decomposition product of THC, it could not account for the decrease in the concentration of THC over a period of time when the latter is kept under conditions suitable for decomposition (12). Turner and ElSohly (13) addressed this problem and proposed a possible pathway for the decomposition of THC to CBN which involvesformation of epoxy and hydroxylated intermediates. These include 9,10-dihydroxy-D6a(10a)-THC (racemic mixture) and 8,9-dihydroxy- D6a(10a)-THC (racemic mixture). They found that these intermediates could be detected only by gas chromatography as their trimethyl silyl (TMS) derivatives. They also indicated that these compounds were susceptible to heat and acid and that the final product was CBN.
In the present report, the change in the level of THC and CBN in stored marijuana was studied over a four-year period. THC and CBN were analysed annually in marijuana stored at room temperature and a correlation was developed between the ratio of CBN to THC and the age of the plant material. The empirical correlation could be used to estimate the age of a given marijuana sample.
.....the rest:
http://www.unodc.org/unodc/en/data-and-analysis/bulletin/bulletin_1997-01-01_1_page008.html
Sections
ABSTRACT
Introduction
Experimental basis
Results and discussion
References
Author: S. A. ROSS, M. A. ELSOHLY
Creation Date: 1999/12/01
CBN and D9-THC concentration ratio as an indicator of the age of stored marijuana samples*
S. A. ROSS
National Center for the Development of Natural Products, Research Institute of Pharmaceutical Sciences, Department of Pharmacognosy, School of Pharmacy, University of Mississippi, Oxford, Mississippi, United States of America
M. A. ELSOHLY
National Center for the Development of Natural Products, Research Institute of Pharmaceutical Sciences, Department of Pharmaceutics, School of Pharmacy, University of Mississippi, Oxford, Mississippi, United States of America
ABSTRACT
The concentration of D9-tetrahydrocannabinol (THC) and cannabinol (CBN) in cannabis plant material (marijuana) of different varieties stored at room temperature (20-22o Celsius (C)) over a four-year period was determined. The percentage loss of THC was proportional to the storage time. On average, the concentration of THC in the plant material decreased by 16.6% ±7.4 of its original value after one year and 26.8% ±7.3, 34.5% ±7.6 and 41.4% ±6.5 after two, three and four years, respectively. A relationship between the concentration ratio of CBN to THC and the storage time was developed and could serve as a guide in determining the approximate age of a given marijuana sample stored at room temperature.
Introduction
The stability of (-)-D9-tetrahydrocannabinol (D9-THC) has been the subject of several investigations (1-13). In 1970, Liskow (1) reported that marijuana deteriorates during storage at room temperature because of the loss of D9-THC at a rate of 3 to 5 per cent a month. Shoyama and others (3) were able to isolate cannabinolic acid (CBNA) from stored hemp but not from fresh hemp, and concluded that conversion of tetrahydrocannabinolic acid (THCA) to CBNA was effected by ultraviolet light and by storage and heat. The same conclusion was reached by Turner and others (4, 5), who reported that THC disappeared at a rate of 3.83, 5.38 and 6.92 per cent per year over two years when stored at -18o, 4o, and 22o C, respectively. The loss of THC was essentially complete at 37o C and 50o C. Fairbairn and others (6) reported that carefully prepared herbal or resin cannabis products are reasonably stable for one to two years if stored in the dark at room temperature.
Razdan and others (2) found thatD9-THC is much less stable than D8-THC and is converted mainly to CBN. The degradation of D9-THC to CBN in the plant material on storage was also proposed by Waller and others (7), Razdan and others (8), El-Kheir and others (9), Hanus and others (10) and Yotoriyana and others (11). Although CBN is the major observed decomposition product of THC, it could not account for the decrease in the concentration of THC over a period of time when the latter is kept under conditions suitable for decomposition (12). Turner and ElSohly (13) addressed this problem and proposed a possible pathway for the decomposition of THC to CBN which involvesformation of epoxy and hydroxylated intermediates. These include 9,10-dihydroxy-D6a(10a)-THC (racemic mixture) and 8,9-dihydroxy- D6a(10a)-THC (racemic mixture). They found that these intermediates could be detected only by gas chromatography as their trimethyl silyl (TMS) derivatives. They also indicated that these compounds were susceptible to heat and acid and that the final product was CBN.
In the present report, the change in the level of THC and CBN in stored marijuana was studied over a four-year period. THC and CBN were analysed annually in marijuana stored at room temperature and a correlation was developed between the ratio of CBN to THC and the age of the plant material. The empirical correlation could be used to estimate the age of a given marijuana sample.
.....the rest:
http://www.unodc.org/unodc/en/data-and-analysis/bulletin/bulletin_1997-01-01_1_page008.html
