Phencyclidine disposition after intravenous and oral doses

[3H]-Phencyclidine (PCP) hydrochloride was given in intravenous (0.1 or 1 mg) or oral (1 mg) doses to male subjects. After 1 mg IV, drug and metabolites were recovered in urine (72.8 +/- 4.0% of dose), feces (4.7 +/- 0.9%), and perspiration. Fecal excretion was low (3.4 +/- 0.4%) after oral dosing and oral bioavailability was estimated at 72%. PCP comprised 16% of urinary radioactivity with 31% consisting of enzymatically hydrolyzable conjugates of hydroxylated metabolites. Both cis and trans isomers of 4-phenyl-4-(1-piperidinyl)cyclohexanol were found. Maximum average plasma PCP concentrations of 2.7 to 2.9 ng/ml were observed after oral and intravenous 1-mg doses. Blood/plasma ratios were approximately 1.0 and plasma binding was about 65%. Parent drug was found in saliva. Apparent terminal phase half-lifes averaged 21 +/- 3 hr (harmonic mean 17 hr, range 7 to 46 hr). The volume of distribution averaged 6.2 +/- 0.3 l/kg. Renal clearances were variable, but the average was 9% of the total clearance. Thus, PCP is cleared principally by metabolism.

The metabolism of delta 9-tetrahydrocannabinol and related cannabinoids in man

The metabolism of delta 9-tetrahydrocannabinol (THC) and related cannabinoids in man has been studied in detail utilizing intravenous, oral, and smoking routes of administration. The general pattern of metabolism was the same in all studies involving THC and related cannabinoids. Microsomal hydroxylation allylic to the delta 9-THC double bond occurs, the major product resulting in formation of an 11-CH2OH moiety; minor hydroxylation occurs on the C-8 carbon. Nonmicrosomal oxidation of the resultant 11-OH-delta 9-THC to 11-nor-delta 9-THC-9-carboxylic acid and to other more polar acids generates the major terminal metabolic products. After oral administration, approximately equal quantities of THC and its highly active 11-hydroxymetabolite were formed, whereas the latter metabolite is a minor constituent after administration by intravenous or smoking routes. Initial pharmacokinetic analyses of the data show that the mean terminal-phase (beta-phase) plasma half-life after intravenous administration of THC was about 30 hours; after oral administration, it was 23 hours. No significant statistical difference was noted between men and women as to metabolic routes or plasma terminal-phase half-lives.

Metabolism and disposition of naltrexone in man after oral and intravenous administration

The metabolism and elimination of [15, 16,-3H2]naltrexone was studied in man after oral and intravenous administration. The same metabolites, although in varying proportions, were observed in both cases; conjugated naltrexone and conjugated and unconjugated 6 beta-naltrexol were the major metabolites observed in plasma, urine, and feces. 2-Hydroxy-3-O-methyl-6 beta-naltrexol was found in minor quantities. Naltrexone was almost completely absorbed after oral administration. After oral and intravenous administration of naltrexone, about 60% of the dose was recovered in the urine in 48 and 72 hr, respectively. The route of administration did not significantly affect urinary clearance values obtained for unconjugated or conjugated naltrexone and 6 beta-naltrexol. The route of administration significantly affected terminal plasma half-life values obtained for unconjugated naltrexone (2.7 hr, iv; 8.9 hr, oral), but had little effect on comparable values obtained for total drug, conjugated naltrexone, and unconjugated and conjugated 6 beta-naltrexol. Combined gas chromatography-mass spectrometry was used to validate the presence of naltrexone, 6 beta-naltrexol, and 2-hydroxy-3-O-methyl-6 beta-naltrexol in urine.

Plant antitumor agents. 18. Synthesis and biological activity of camptothecin analogues

Four analogues, 10-methoxy (20), 12-aza (29), benz[j] (36), and 18-methoxy (38), of camptothecin were obtained by total synthesis. The two water-soluble analogues, 10-[(carboxymethyl)oxy]- (24) and 10-[2'-(diethylamino)-ethoxy]-20(S)-camptothecin (26), with intact ring E were prepared from natural 10 hydroxycamptothecin (3). In general, there was a good correlation between in vitro 9KB cytotoxicity and activity in the P-388 leukemia system. While the aza analogue 29 was active in P-388 only at a much higher dose level than natural camptothecin (1), the 18-methoxy analogue 38 exhibited activity comparable to that of 1. The water-soluble derivative 24 was inactive. The amine hydrochloride 26 showed excellent activity at a high dose level. This could be due to its hydrolysis to 3. dl-Camptothecin (17) was roughly half as active as 1, indicating that the l isomer is inactive.

Plant antitumor agents. XVI. 6alpha-Senecioyloxy-chaparrinone, a new antileukemic quassinoid from Simaba multiflora

Fractionation of Simaba multiflora A. Juss. guided by bioassay has resulted in the isolation of a new antileukemic quassinoid 6alpha-senecioyloxychaparrinone (2) and the previously reported quassinoid chaparrinone (3). The structure of the former has been established by spectral and chemical methods. Compound 2 has high anti-neoplastic activity against several mouse leukemia systems (P-388, L-1210 and in solid-tumor B-16 melanoma). This demonstrates for the first time that the presence of a C-15 ester function is not required for antineoplastic activity in the quassinoids.

Comparison of gas chromatography mass spectrometry methods for the determination of delta9-tetrahydrocannabinol in plasma

A method for the identification of delta9-tetrahydrocannabinol by gas chromatography mass spectrometry has been developed, and this method has been compared with other techniques, such as detection via thin-layer chromatography using tritium labeled delta9-tetrahydrocannibinol and a dual gas chromatographic method. The gas chromatographic mass spectrometric method was found to be equal or superior to other techniques and has the added advantage of being highly specific for the compound analyzed. An alternate approach using chemical ionization is also described; however, this procedure does not show significant advantages over the electron impact method. These methods show a practical lower detection limit of 500 pg ml-1 of plasma in clinical practice.

Biotransformation products of 3,4,4'-trichlorocarbanilide in rat, monkey, and man

3,4,4'-Trichlorocarbanilide (TCC), uniformly labeled with 14C in the monochloro ring, was administered to rats, rhesus monkeys, and humans. Radioactive materials in the plasma and urine of all three species and in the bile of rats and monkeys were separated by high performance liquid chromatography. The chromatography showed great similarity between the monkey and the human. Principal metabolites common to all species were the sulfate and glucuronide conjugates of 2'-, 3'-, and 6-hydroxy-TCC. The rat also produced the glucuronide and sulfate conjugates of 2',6-dihydroxy-TCC. The major urinary excretion products found in humans and monkeys were the N- and N'-TCC glucuronides.

The metabolism and toxicity of halogenated carbanilides. Biliary metabolites of 3,4,4'-trichlorocarbanilide and 3-trifluoromethyl-4,4'-dichlorocarbanilide in the rat

In separate experiments, after repeated oral administration of 3,4,4'-trichlorocarbanilide (TCC) and 3-trifluoromethyl-4,4'-dichlorocarbanilide (TFC) to rats, the biliary metabolites of each were isolated and identified. The major TCC biliary metabolite was found to be 2'-hydroxy-TCC. This compound was isolated mainly from the nonconjugated and the glucuronide fractions. Other metabolites present in substantial quantities were 6-hydroxy-TCC and 2',6-dihydroxy-TCC mainly as glucuronides and 3'-hydroxy TCC mainly as the sulfate conjugate. Small amounts of 3',6-dihydroxy-TCC were isolated from each of the fractions. No unchanged TCC was found in the bile. Only traces of other metabolites were found, and no N-hydroxylated products were observed. The major TFC biliary metabolite was the glucuronide conjugate of 2'-hydroxy-TFC. The only other metabolite of TFC was 3'-hydroxy-TFC, which was the predominant metabolite in the sulfate-conjugated fraction.

Isolation and chemical characterization of antitumor agents from plants

This paper reviews methods which have evolved at the Research Triangle Institute during the last 15 years for the isolation and characterization of antitumor agents from plants. The isolation procedures stress mild, nonchemical methods. Solvent partition and the Craig Counter Current Distribution are used during the early stages of fractionation. Subsequent purification involves many types of chromatography: adsorption, partition, thin-layer, preparative thin layer, gel-exclusion, and medium- and high-pressure liquid chromatography. The pure compound is crystallized from a suitable solvent. The fractionation is monitored with in vitro and in vivo bioassays. Physical methods used for structure determination are: ultraviolet, infrared, and nuclear magnetic resonance spectrometry, and X-ray crystallography.

Analytical methods for the determination of cannabinoids in biological media

A pharmacokinetic study of the blood plasma levels in man of delta9-tetrahydrocannabinol, 11-hydroxy-delta9-tetrahydrocannabinol and cannabinol has been carried out by means of combined gas chromatographic-mass spectral analysis. In some cases comparison of the data was obtained on the same sample using thin layer chromatography of radiolabeled samples and electron capture gas-liquid chromatography. For the mass spectral studies appropriately deuterium labeled analogs of the previously named compounds were used both as internal standards and as a carrier for the relatively small amounts of nonlabeled drug present in plasma. Blood samples were obtainted at periodic intervals up to 24 hours from volunteers receiving 4-5 mg delta9-THC intravenously. After extraction and "clean-up" by Sephadex chromatography, the extracts were concentrated and subjected to glc-ms in the electron impact (ei) mode or alternatively with a chemical ionization (ci) source, in which case preliminary chromatography could be omitted. In all cases calibration curves were obtained from replicate analyses of spiked plasma containing the internal standard and various quantities of the cannabinoid under analysis. A typical biphasic elimination of the drug was observed with rapid elimination of delta9-THC from the blood over a period of 40 min followed by a much slower elimination up to 24 hours. The experimental data show that 11-hydroxy-delta9-THC is found in the plasma in quantities only about one-twentieth to one-twenty-fifth the values found for delta9-THC. Cannabinol was not found in significant quantities. Good agreement was obtained between the mass spectral analyses and the thin layer chromatography or electron capture gas-liquid chromatographic procedures.

A complex pattern of disposition of phenytoin in severe intoxication

A 5-year-old child developed phenytoin (diphenylhydantoin, DPH) toxicity after receiving 500 mg of the drug daily for 3 weeks. Plasma, urine, and duodenal fluid were collected for assay of DPH and its metabolites. The peak plasma concentration of DPH was 108 mug/ml, and the decline in plasma level did not fit first-order kinetics. The para-hydroxy, meta-hydroxy, and dihydrodiol metabolites of DPH were measured in urine; duodenal aspirate contained both DPH and the para-hydroxy metabolite. Plasma pH may affect distribution of DPH since in vitro binding of DPH to human albumin increased as pH increased.