Pharmacokinetics of nabilone, a psychotropically active 9-ketocannabinoid, in the dog. Utilization of quantitative selected ion monitoring and deuterium labeling

Quantitative selected ion monitoring methods for the determination of plasma concentrations of nabilone, a psychotropically active 9-ketocannabinoid, and two carbinol metabolites using deuterium labeled internal standards are described. These specific methods have a lower limit of sensitivity of about 2 pmol ml-1 with a coefficient of variation of less than 4%. The utility of these methods was demonstrated by in vivo studies of single dose and steady state pharmacokinetics of nabilone and its carbinol metabolites in the dog.

Effect of a nitrogen analog of tetrahydrocannabinol on cancer pain

Two consecutive, randomized, double-blind trials were performed to test the analgesic properties of a synthetic nitrogen analog of tetrahydrocannabinol (NIB). In the first trial, the test preparation was superior to placebo and approximately equivalent to 50 mg of codeine phosphate. In the second study, the tetrahydrocannabinol analog was superior to placebo and to 50 mg secobarbital. NIB is not useful clinically because of the frequency of side effects.

A model for evaluation of antianxiety drugs with the use of experimentally induced stress: Comparison of nabilone and diazepam

Volunteer subjects were used to compare a potential antianxiety drug (nabilone, 2-mg single doses) with a standard drug (diazepam, 5-mg single doses). A double-masked design with placebo control was used. Volunteer subjects were selected on the basis of high levels of train anxiety and were tested by two anxiety-inducing procedures--the mirror drawing test and the Stroop color-word test. Anxiety induced by the experimental procedure was alleviated by diazepam and, to a lesser extent, by nabilone. Since doses of the two drugs may not have been equivalent, or the time courses identical, conclusions about their relative efficacy must be guarded. The experimental model is unusual in that antianxiety drugs can be tested in volunteer subjects for true antianxiety effects rather than for side effects, such as cognitive or motor impairment, sleepiness, or other signs of central nervous system depression.

Nabilone: a potent antiemetic cannabinol with minimal euphoria

Nabilone is a cannabinol derivative which has potent central antiemetic effects in animals. We observed that the drug significantly reduced the nausea and vomiting induced by cancer chemotherapy in 10 of 13 patients who were refractory to conventional antiemetics. A dose-response effect was apparent. The drug was generally well-tolerated, although it also had sedative effects. Additionally, dizziness, decreased coordination and postural hypotension were observed in some patients. Euphoric effects of the agent were minimal at antiemetic dosage levels.

A cannabinoid with cardiovascular activity but no overt behavioral effects

Abnormal-delta8-tetrahydrocannabinol (ABN-delta8-THC) failed to elicit central nervous system and cardiovascular effects in laboratory animals. Abnormal-cannabidiol (ABN-CBD) was also devoid of overt behavioral effects but produced marked hypotension with only slight bradycardia in anesthesized dogs.

Physiologic disposition of nabilone, a cannabinol derivative, in man

Nabilone is a cannabinoid that is being evaluated in man as a potentially useful psychoactive drug. We found that nabilone was readily absorbed from the human gastrointestinal tract when administered orally as a coprecipitate with polyvinyl-pyrrolidone. The absorbed drug disappeared from plasma rather rapidly (half-life, approximately 2 hr), evidently due to extensive tissue distribution and rapid metabolism. The metabolites of nabilone persist in plasma for extended periods (half-life of total radioactivity exceeds 20 hr). Circulating metabolites include isomeric carbinols formed by reduction of the ketone in the 9-position of nabilone. Nabilone is eliminated in feces (about 65% of dose) and urine (20%). The excretory products in urine have not been identified, but metabolites that are labile to hydrolysis by beta-glucuronidase or sulfatase do not appear to be formed in significant amounts. A metabolite of nabilone in feces has been identified as a diol formed by reduction of the 9-keto group plus oxidation at the penultimate carbon of the dimethylheptyl side chain. The long duration of action of nabilone in the face of rapid and extensive metabolic elimination suggests that the pharmacologic effects, at least in part, may be exerted by one or more active metabolites.

Synthesis and characterization of glucuronides of Cannabinol, cannabidiol, delta9-tetrahydrocannabinol and delta8-tetrahydrocannabinol

Partially purified glucuronyltransferase immobilized on beaded sepharose has been used to synthesize the glucuronide conjugates of cannabinol, cannabidol, delta9-tetrahydrocannabinol and delta8-tetrahydrocannabinol. Trimethylsilylated methyl esters and per(trimethylsilyl) derivatives of these conjugates have been characterized by their gas chromatographic retention times and their electron impact and ammonia chemical ionization mass spectra.

Immunosuppressive effects of 8,9-epoxyhexahydrocannabinol (EHHC)

8,9-Epoxyhexahydrocannabinol (EHHC)-treated mice showed an inhibition of both humoral and cell-mediated immunity. The hemolytic plaque forming assay was employed to determine both the IgM and IgG antibody response. The effect of EHHC on IgM antibody production was measured in BDG1 male mice given X 10(8) sheep erythrocytes i.p. followed 24 and 48 hours later by i.p. injections of EHHC. EHHC produced a dose-dependent inhibition of plaque forming cells (PFC)/10(6) spleen cells and PFC/spleen on days 3, 4 and 5 after antigen administration. On day 4 the ED50 for PFC/10(6) spleen cells and PFC/spleen was 28 and 18 mg/kg, respectively. Peak response to IgG antibody production was observed on day 9. EHHC (100 mg/kg) administered i.p. 48 hours after antigen produced a 58 and 46% suppression of PFC/10(6) leucocyte on days 7 and 9, respectively. CDF1 male mice received 100 microng of Cornybacterium parvum in the left footpad. Two days after sensitization, EHHC was administered in doses of 0.75 to 50 mg/kg i.p. A challenge dose of 100 microng of Cornybacterium parvum was injected into the right footpad on day 6 and footpad swelling was measured 24 hours later by mercury displacement. EHHC at a dose of 0.78 mg/kg produced a 95% inhibition of the delayed-type hypersensitivity response. These studies showed that EHHC inhibits both the humoral and cellular arm of the immune response.

9-nor-9beta-hydroxyhexahydrocannabinol, a cannabinoid with potent antinociceptive activity: comparisons with morphine

The effects of (+/-)9-nor-9beta-hydroxyhexahydrocannabinol (beta-HHC) on tail-flick test activity and the accumulation of newly synthesized dopamine and norepinephrine were studied in the male albino mouse. The same parameters were also studied in naloxone-pretreated and morphine-tolerant mice. beta-HHC was about equipotent with morphine in the mouse tail-flick (ED50 = 7.12 mg/kg). The cannabinoid also produced dose-dependent increases in the accumulation of newly synthesized DA and NE. Pretreatment with 2 mg/kg of naloxone antagonized both the tail-flick activity and blocked the increases in catecholamine synthesis produced by beta-HHC. Cross-tolerance between beta-HHC and morphine did not exist in regard to either tail-flick activity or increased catecholamine synthesis. These studies suggest that beta-HHC may share some properties with the narcotic analgesics but that significant differences exist. Furthermore, these studies offer further evidence for the involvement of catecholamine containing neurons in the central mediation of the tail-flick response.

The separation, identification, and quantitation of cannabinoids and their tau=butyldimethylsilyl, trimethylsilylacetate, and diethylphosphate derivatives using high-pressure liquid chromatography, gas-liquid chromatography, and mass spectrometry

Methods for the separation, identification, and quantitation, of cannabinoids present in hashish have been developed. These methods include high-pressure liquid chromatographic and gas-liquid chromatographic separation of cannabinol, delta 9-tetrahydrocannabinol, delta 8-tetrahydrocannabinol, and cannabidiol as well as their tau-butyidimethylsilyl either and trimethylsilylacetate derivatives. The necessity for internal standards; the sensitivity of the HPLC method; and some mass spectral fragmentation pathways for the tau-butyldimethylsily, trimethylsilylacetate, and diethylphosphate derivatives are discussed.

Hashish. Unsaturated side-chain analogues of delta8-tetrahydrocannabinol with potent biological activity

Two delta8-THC derivatives, 4a and 4b, with functionalized side chains were synthesized. Treatment of (+)-trans-p-mentha-2,8-dien-1-ol with the resorcinal 2b followed by removal of the dithiol group with HgO--BF3-Et2O gave the aldehyde 3b. A Wittig reaction of dimethyl (2-oxoheptyl)phosphate with 3b furnished 4a, which was reduced to 4b. Compounds 4a and 4b showed potent cannabinoid-like activity in mice.