Pharmacokinetics, metabolism, bioavailability, tissue distribution and excretion studies of 16α-hydroxycleroda-3, 13(14) Z -dien-15, 16-olide-a novel HMG-CoA reductase inhibitor.

The present study was designed to investigate the oral bioavailability, metabolism, tissue disposition and excretion of 16α-hydroxycleroda-3, 13(14) Z -dien-15, 16-olide (4655K-09), a novel HMG-CoA reductase inhibitor in male Sprague Dawley (SD) rats. Tissue distribution, oral bioavailability and excretion studies of 4655K-09 were carried out in male SD rats through oral administration at active dose of 25 mg/kg. In vitro metabolism studies were carried out in different rat tissues S9 fractions to evaluate primary organs responsible for conversion of parent 4655K-09 to its major active metabolite K-9T. The quantification of both parent and metabolite in different biological matrices was performed using LC-MS/MS method. The oral bioavailability of 4655K-09 was found to be 30% in male SD rats. The biodistribution study was illustrated in terms of tissue to plasma area under curve (AUC)0-∞ ratio (Kp) revealed the preferential distribution of 4655K-09 and K-9T to target site, i.e. liver. In vitro tissue S9 fraction stability assay demonstrated the rapid and extensive metabolic conversion of 4655K-09 to K-9T, primarily through liver and kidney. Very low amount of parent and metabolite were excreted unchanged in urine and faeces. The present studies established 4655K-09 bioavailability, tissue disposition, excretion and tissue-specific metabolic conversion to K-9T which could assist in its further development as antihyperlipidemic drug.

Salvia divinorum: toxicological aspects and analysis in human biological specimens.

The identification and quantitation of the main psychoactive component of Salvia divinorum (salvinorin A) in biological specimens are crucial in forensic and clinical toxicology. Despite all the efforts made, its uncontrolled abuse has increased quickly, exposing its users' health to serious risks both in the short and long term. The use of alternative biological matrices in toxicological analyzes can be advantageous as complementary postmortem samples, or in situations when neither blood nor urine can be collected; they may be useful tools in those determinations, providing important information about prior exposure. The aim of this article is to present a brief summary of legal aspects of Salvia divinorum and salvinorin A, including the methods used for the determination of the latter in biological matrices.

Time course of pharmacokinetic and hormonal effects of inhaled high-dose salvinorin A in humans.

Salvinorin A is a kappa opioid agonist and the principal psychoactive constituent of the Salvia divinorum plant, which has been used for hallucinogenic effects. Previous research on salvinorin A pharmacokinetics likely underestimated plasma levels typically resulting from the doses administered due to inefficient vaporization and not collecting samples during peak drug effects. Six healthy adults inhaled a single high dose of vaporized salvinorin A (n = 4, 21 mcg/kg; n = 2, 18 mcg/kg). Participant- and monitor-rated effects were assessed every 2 min for 60 min post-inhalation. Blood samples were collected at 13 time points up to 90 min post-inhalation. Drug levels peaked at 2 min and then rapidly decreased. Drug levels were significantly, positively correlated with participant and monitor drug effect ratings. Significant elevations in prolactin were observed beginning 5 min post-inhalation and peaking at 15 min post-inhalation. Cortisol showed inconsistent increases across participants. Hormonal responses were not well correlated with drug levels. This is the first study to demonstrate a direct relationship between changes in plasma levels of salvinorin A and drug effects in humans. The results confirm the efficacy of an inhalation technique for salvinorin A.

Immediate and Persistent Effects of Salvinorin A on the Kappa Opioid Receptor in Rodents, Monitored In Vivo with PET.

Monitoring changes in opioid receptor binding with positron emission tomography (PET) could lead to a better understanding of tolerance and addiction because altered opioid receptor dynamics following agonist exposure has been linked to tolerance mechanisms. We have studied changes in kappa opioid receptor (KOR) binding availability in vivo with PET following kappa opioid agonist administration. Male Sprague-Dawley rats (n=31) were anesthetized and treated with the (KOR) agonist salvinorin A (0.01-1.8 mg/kg, i.v.) before administration of the KOR selective radiotracer [(11)C]GR103545. When salvinorin A was administered 1 min prior to injection of the radiotracer, [(11)C]GR103545 binding potential (BPND) was decreased in a dose-dependent manner, indicating receptor binding competition. In addition, the unique pharmacokinetics of salvinorin A (half-life ~8 min in non-human primates) allowed us to study the residual impact on KOR after the drug had eliminated from the brain. Salvinorin A was administered up to 5 h prior to [(11)C]GR103545, and the changes in BPND were compared with baseline, 2.5 h, 1 h, and 1 min pretreatment times. At lower doses (0.18 mg/kg and 0.32 mg/kg) we observed no prolonged effect on KOR binding but at 0.60 mg/kg salvinorin A induced a sustained decrease in KOR binding (BPND decreased by 40-49%) which persisted up to 2.5 h post administration, long after salvinorin A had been eliminated from the brain. These data point towards an agonist-induced adaptive response by KOR, the dynamics of which have not been previously studied in vivo with PET.

Lack of effect of sublingual salvinorin A, a naturally occurring kappa opioid, in humans: a placebo-controlled trial.

RATIONALE: Salvinorin A (SA) is a highly selective kappa opioid receptor agonist and the putative psychoactive compound in Salvia divinorum (SD), an increasingly abused hallucinogenic plant. OBJECTIVES: The objectives of this study were to characterize the physiological and subjective effects of SA versus placebo and measure drug and metabolite levels. METHODS: Sublingual SA doses up to 4 mg were administered in dimethyl sulfoxide/polyethylene glycol 400 solution to eight SD-experienced subjects using a placebo-controlled ascending-dose design. RESULTS: No dose of SA produced significantly greater physiological or subjective effects than placebo. Furthermore, effects did not resemble reported "typical" effects of smoked SD. SA was detectable in plasma and urine, but was, in most cases, below the reliable limit of quantification (0.5 ng/mL). CONCLUSIONS: Our results suggest that the sublingual bioavailability of SA is low. Higher doses, alternate formulations, or alternate routes of administration will be necessary to study the effects of SA in humans.

Salvinorin A and derivatives: protection from metabolism does not prolong short-term, whole-brain residence.

Salvinorin A (SA) is a potent kappa opioid agonist with a brief duration of action. Consistent with this, our previous positron emission tomography (PET) studies of carbon-11 labeled SA showed that brain levels decrease rapidly after intravenous administration. SA is rapidly metabolized, giving the much less potent salvinorin B (SB), which is presumed to be responsible in part for SA's brief duration of action. To test this, we labeled the metabolically stable methyl ester of SA and SB with carbon-11 and compared their pharmacokinetics by PET imaging after intravenous administration to baboons. Labeling of salvinorin B ethoxymethyl ether (EOM-SB), a derivative with greater potency and resistance to metabolism, provided an additional test of the role of metabolism in brain efflux. Plasma analysis confirmed that SB and EOM-SB exhibited greater metabolic stability than SA. However, the three compounds exhibited very similar pharmacokinetics in brain, entering and exiting rapidly. This suggests that metabolism is not solely responsible for the brief brain residence time of SA. We determined that whole-brain concentrations of EOM-SB declined more slowly than SA after intraperitoneal administration in rodents. This is likely due to a combination in EOM-SB's increased metabolic stability and its decreased plasma protein affinity. Our results suggest that protecting salvinorin A derivatives from metabolism will prolong duration of action, but only when administered by routes giving slow absorption.

Evaluation of the transport, in vitro metabolism and pharmacokinetics of Salvinorin A, a potent hallucinogen.

Salvinorin A is an unregulated potent hallucinogen isolated from the leaves of Salvia divinorum. It is the only known non-nitrogenous kappa-opioid selective agonist, and rivals synthetic lysergic acid diethylamide (LSD) in potency. The objective of this study was to characterize the in vitro transport, in vitro metabolism, and pharmacokinetic properties of Salvinorin A. The transport characteristics of Salvinorin A were assessed using MDCK-MDR1 cell monolayers. The P-glycoprotein (P-gp) affinity status was assessed by the P-gp ATPase assay. In vitro metabolism studies were performed with various specific human CYP450 isoforms and UGT2B7 to assess the metabolic characteristics of Salvinorin A. Cohorts (n = 3) of male Sprague Dawley rats were used to evaluate the pharmacokinetics and brain distribution of Salvinorin A (10 mg/kg, intraperitoneal (i.p.) over a 240-min period. A validated UV-HPLC and LC/MS/MS method was used to quantify the hallucinogen concentrations obtained from the in vitro and in vivo studies, respectively. Salvinorin A displayed a high secretory transport in the MDCK-MDR1 cells (4.07 +/- 1.34 x 10(-)5 cm/s). Salvinorin A also stimulated the P-gp ATPase activity in a concentration (5 and 10 microM)-dependent manner, suggesting that it may be a substrate of (P-gp). A significant decrease in Salvinorin A concentration ranging from 14.7 +/- 0.80% to 31.1 +/- 1.20% was observed after incubation with CYP2D6, CYP1A1, CYP2C18, and CYP2E1, respectively. A significant decrease was also observed after incubation with UGT2B7. These results suggest that Salvinorin A maybe a substrate of UGT2B7, CYP2D6, CYP1A1, CYP2E1, and CYP2C18. The in vivo pharmacokinetic study showed a relatively fast elimination with a half-life (t1/2) of 75 min and a clearance (Cl/F) of 26 L/h/kg. The distribution was extensive (Vd of 47.1 L/kg); however, the brain to plasma ratio was 0.050. Accordingly, the brain half-life was relatively short, 36 min. Salvinorin A is rapidly eliminated after i.p. dosing, in accordance with its fast onset and short duration of action. Further, it appears to be a substrate for various oxidative enzymes and multi-drug resistant protein, P-gp.

In vitro stability and metabolism of salvinorin A in rat plasma.

Salvinorin A is the main active psychoactive ingredient in Salvia divinorum, a Mexican plant that has been widely available as a hallucinogen in recent years. The aims of this study were to investigate the stability of salvinorin A in rat plasma, esterases responsible for its degradation, and estimation of the degradation products. The apparent first-order rate constants of salvinorin A at 37 degrees C, 25 degrees C, and 4 degrees C were 3.8 x 10(-1), 1.1 x 10(-1), and < 6.0 x 10(-3) h(-1), respectively. Salvinorin A degradation was markedly inhibited by the addition of sodium fluoride, an esterase inhibitor. Moreover, phenylmethylsulfonyl fluoride (serine esterase inhibitor) and bis-p-nitrophenylphosphate (carboxylesterase inhibitor) also inhibited salvinorin A degradation. In contrast, little or no suppression of the degradation was seen with 5,5'-dithiobis-2-nitrobenzoic acid (arylesterase inhibitor),ethopropazine (butyrylcholinesterase inhibitor), and BW284c51 (acetylcholineseterase inhibitor). These findings indicated that carboxylesterase was mainly involved in the salvinorin A hydrolysis in rat plasma.4. The degradation products of salvinorin A estimated by liquid chromatography-mass spectrometry included the deacetylated form (salvinorin B) and the lactone-ring-open forms of salvinorin A and salvinorin B. This lactone-ring-opening reactions were involved in calcium-dependent lactonase.

Encapsulation and release characteristics of DCTN/PLGA microspheres.

In the present study, poly (D,L-lactic-co-glycolic)-acid microspheres containing trans-Dehydrocrotonin (DCTN) were prepared by the double emulsion method. The hypoglycemic activity of DCTN-loaded microspheres was monitored in normal glycemic mice after administration of a daily dose of DCTN (50 mg kg(-1) body weight) for 7 days. Spherical microspheres with two populations of particles with 3.20 +/- 0.10 and 7.60 +/- 0.70 microm mean diameter size microm were observed. The encapsulation efficiency of DCTN was 85.5 +/- 3.9%. The in vitro kinetic profile of DCTN from PLGA-microspheres was initially fast (burst effect of 19.4% at 2 h). Such a burst step was maintained until achieving 35.7+/-2.0% at 7h, followed by a gradual release of DCTN attaining a maximum drug release at 55.7 +/- 2.6% within 30 h. DCTN was able to reduce glucose levels (14.3%) of normal glycemic animals and this effect was improved by its encapsulation into microspheres (26.8%). The optimum glucose levels in the blood of animals treated with DCTN suspension and DCTN-loaded microspheres were 119.21 +/- 19.75 mg dL(-1) at day 5 and 103.08 +/- 18.88 mg dL(-1) at day 7, respectively. DCTN-loaded microspheres are thus offered as a potential delivery system for the treatment of metabolic diseases characterized by hyperglycemia.

Pharmacokinetics of the potent hallucinogen, salvinorin A in primates parallels the rapid onset and short duration of effects in humans.

Salvia divinorum, a mint plant originally used by the Mazatecs of Oaxaca, Mexico in spiritual rituals has gained popularity, in smoked form, as a legal hallucinogen in the United States and Europe. Abuse results in rapid onset and short-lasting effects that include visual hallucinations and motor-function impairment. Salvinorin A, the psychoactive component of S. divinorum, is a uniquely potent agonist at kappa-opioid receptors, targets for new therapeutic drugs. We labeled salvinorin A with C-11 by acylation of salvinorin B with [11C]-acetyl chloride to study whether its kinetic behavior in the brain parallels its uniquely fast, yet brief physiological effects. Positron emission tomography (PET) studies performed in 6 adult female baboons indicated extremely rapid brain uptake reaching a peak accounting for 3.3% of the total administered dose in 40 s and clearing with a half-life of 8 min. [11C]-salvinorin A was distributed throughout the brain with the highest concentration in the cerebellum and a notable concentration in the visual cortex, perhaps accounting for its physiological effects when smoked. Naloxone administration did not reduce the overall concentration of [11C]-salvinorin A significantly nor did it change its regional distribution. Peripheral organ kinetics suggested at least two modes of metabolism and excretion occur: through the renal and biliary systems. Our findings have revealed that the exceptionally rapid uptake and brief duration of salvinorin A in the brain match the time-course of visual hallucinations for S. divinorum when smoked. The effects of salvinorin A may occur at <10 mug in the human brain, emphasizing its remarkable potency.