Mahmoud A. ElSohly,1,2 Ph.D.; Samir A. Ross,1,3 Ph.D.; Zlatko Mehmedic,1 MS; Rawia Arafat,1 B.S.; Bao Yi,1 B.S.; and Benjamin F. Banahan, III1,4 Ph.D. Potency Trends of ⌬9-THC and Other Cannabinoids in Confiscated Marijuana from 1980–1997 REFERENCE: ElSohly MA, Ross SA, Mehmedic Z, Arafat R, Yi Review of the literature dealing with confiscated marijuana and 9 B, Banahan BF. Potency trends of ⌬ -THC and other cannabinoids other cannabis preparations revealed that analyses were typically in confiscated marijuana from 1980–1997. J Forensic Sci 2000;45(1):24–30. carried out for the identification of the drug for legal or forensic sci- ence purposes (7–10) or to identify the country of origin (11–15). ABSTRACT: The analysis of 35,312 cannabis preparations con- In previous publications (16,17), we have reported on the analy- fiscated in the USA over a period of 18 years for delta-9-tetrahy- sis of different forms of marijuana confiscated between 1972 and drocannabinol (⌬9-THC) and other major cannabinoids is reported. 1983. The present report covers the period of 1980–1997 where the Samples were identified as cannabis, hashish, or hash oil. Cannabis analysis of a total of 35,213 cannabis preparations confiscated in samples were further subdivided into marijuana (loose material, the United States was carried out. Statistical analysis of the differ- kilobricks and buds), sinsemilla, Thai sticks and ditchweed. The ⌬9 data showed that more than 82% of all confiscated samples were in ences in the mean -THC concentration from year to year was the marijuana category for every year except 1980 (61%) and 1981 also carried out to ascertain the trend in the change in marijuana po- (75%). The potency (concentration of ⌬9-THC) of marijuana sam- tency over time. Data on hashish and hash oil are also presented. ples rose from less than 1.5% in 1980 to approximately 3.3% in 1983 and 1984, then fluctuated around 3% till 1992. Since 1992, the potency of confiscated marijuana samples has continuously risen, Experimental going from 3.1% in 1992 to 4.2% in 1997. The average concentra- Samples tion of ⌬9-THC in all cannabis samples showed a gradual rise from 3% in 1991 to 4.47% in 1997. Hashish and hash oil, on the other All samples analyzed in this investigation were confiscated dur- hand, showed no specific potency trends. Other major cannabinoids [cannabidiol (CBD), cannabinol (CBN), and cannabichromene ing the years 1980 through 1997 by law enforcement agencies in (CBC)] showed no significant change in their concentration over the USA including the Drug Enforcement Administration (DEA) the years. as well as state and local police and narcotic agents. Samples were classified according to their physical characteristics into the fol- KEYWORDS: forensic science, marijuana, GC, analysis, po- lowing categories. tency, cannabinoids, ⌬9-THC Cannabis Samples—These are all samples received as the raw plant material which could be classified into: marijuana, sin- Cannabis and its preparations (loose marijuana, kilobricks, buds, semilla, Thai sticks and ditchweed. a) Marijuana: Samples classi- sinsemilla, Thai sticks, hashish and hash oil, etc.) are the most fied under the general type of marijuana are found usually in three widely used group of illicit drugs in the world. Efforts to evaluate forms: i) Loose marijuana: when samples are received in the form the health problems associated with cannabis have produced con- of loose cannabis plant material with leaves, stems and seeds. ii) flicting results (1,2). The different biological effects of cannabis Kilobricks: cannabis compressed in the form of a kilobrick (classi- (3,4) are attributed to the complex chemical composition of the cal Mexican packaging) with leaves, stems and seeds. iii) Buds: plant material (5,6). In addition, the chemical profile of the various cannabis in the form of buds or flowering tops of the female plant variants of marijuana are certainly different and could contribute to with seeds. b) Sinsemilla: cannabis in the form of flowering tops of the variability of results between investigators. Therefore, the the female plant (no seeds). c) Thai sticks: cannabis in the form of chemical analysis of confiscated material becomes important in un- leafy material tied around a small stem, a classical form produced derstanding the health problems associated with the abuse of the in Thailand. d) Ditchweed: Fiber type cannabis grown wild in the drug. Midwestern region of the USA. Hashish Samples—Hashish is composed mainly of the resin of 1 National Center for The Development of Natural Products. Research Insti- the cannabis plant, mixed with some plant particles and shaped into tute of Pharmaceutical Sciences. a variety of forms such as balls, sticks or slabs which are very hard, 2 Departments of Pharmaceutics. dark green or brownish colored. 3 Pharmacognosy, and Pharmacy Administration. 4 School of Pharmacy, University of Mississippi, University, MS. Received 13 Nov. 1998; and in revised form 19 March 1999; accepted 6 April Hash Oil Samples—Hash oil is a liquid or semi-solid preparation 1999. which is basically a concentrated extract of the cannabis plant ma- Copyright © 2000 by ASTM International 24 ELSOHLY ET AL. • POTENCY TRENDS 25 terial. Depending on the process used to prepare hash oil, it is usu- up” gas at the detector. Hydrogen and compressed air were used as ally dark green but could be amber or brownish in color. the combustion gases. All samples used in this study were received by the laboratory The following are the instrument parameters used for monitoring within a few weeks after being seized and the analysis was carried samples; Air—30 psi (400 mL/min); Hydrogen—30 psi (30 out shortly thereafter. Samples were stored at room temperature mL/min); column head pressure—8 psi (1.0 mL/min); split flow with a dedicated air conditioning system keeping the temperature rate—50 mL/min; split ratio—50:1; septum purge flow rate: 5 below 20°C. mL/min; make up gas pressure—20 psi (20 mL/min); injector temp: 240°C; detector temp: 260°C; initial oven temp: 170°C; ini- Domestically Cultivated Cannabis—cannabis preparations tial temp. hold time: 1 min; temp. rate: 10°C/min; final oven temp: known to have been produced from plant material grown in the 250°C; final temp. hold time: 3 min; attenuation: 2; chart speed: USA are classified in the same manner as other confiscated sam- 1.00 cm/min; threshold: 2; peak width: 0.04 min; offset: 10%; run ples, with additional designation as being domestically produced. time: 12 min; integration ON time: 3 min. The instruments were calibrated each time columns were changed and routinely checked 9 Analysis for compliance with the calibration response factor for ⌬ -THC rel- ative to internal standard which was found to be 1. Marijuana—All samples that were primarily classified as cannabis plant material were extracted according to the procedure Results and Discussion previously described (19). Briefly, the samples were manicured in a 12 mesh (0.0555 in. opening) metal sieve to remove seeds and During the last eighteen years (1980–1997), a total of 35,213 stems. Duplicate 0.1 g samples were each extracted with 3 mL of samples of confiscated cannabis preparations representing over internal standard/extracting solution (100 mg of 4-androstene- 7717 tons seized in the USA, have been analyzed for this report. 3,17-dione ϩ 10 mL chloroform ϩ 90 mL methanol) at room tem- Table 1 shows the total number of samples analyzed each year and perature for 1 h. The extracts were withdrawn into disposable trans- the breakdown of the different types of samples as cannabis (ditch- fer pipettes through cotton plugs for filtration and placed in screw- weed, marijuana, sinsemilla, and Thai sticks), hashish and hash oil capped vials. Portions of these extracts are transferred into GC and their relative preponderance. The classification of samples is vials which are then capped and placed on the autosampler. One ␮L carried out by the submitting agency and then verified by the labo- aliquots were injected. ratory upon receipt of the samples. Prior to 1995, there was no clas- sification in the database for ditchweed and, therefore, all ditch- Hashish—Samples were first prepared by grinding to a fine weed samples were classified as marijuana. However, because of powder using a mortar and pestle or an electric blender. Duplicate the interest in monitoring this type of sample and its effect on the 0.1 g samples were then extracted following the procedure outlined overall potency of confiscated marijuana, the classification of for marijuana samples. ditchweed was added to the sample report form in 1995. The data presented in this report on ditchweed prior to 1995 was, therefore, Hash Oil—Duplicate 0.1 g samples were each mixed with 4 mL generated by retrospective review of the analytical data. Any mar- of internal standard solution (50 mg of 4-androstene-3,17-dione ϩ ijuana samples containing less than 1% ⌬9-THC and having a CBD 50 mL absolute ethanol) and allowed to stand under the hood for level greater than its ⌬9-THC level was classified as ditchweed. It 2–4 h. The samples were sonicated for about 5 min, then 20 mL of is evident from Table 1 that cannabis represents the overwhelming absolute ethanol were added to each sample and sonicated again. majority of the samples confiscated in the USA with hash oil rep- Each extract was transferred into a vial. One ␮L aliquots of the ex- resenting less than 1% of the samples over the last ten years and tracts were injected into the GC.