buprenorphine and oripavine

Buprenorphine was synthesized from oripavine by a sequence involving the conversion of oripavine into its cyclopropylmethyl quaternary salt, N-demethylation with thiolate to N-cyclopropylmethyl nororipavine, and conversion of this material to the title compound by previously available methods. The new synthesis avoids toxic reagents used previously, is shorter, and proceeds in comparable yields. Experimental and spectral data are provided for all new compounds.

Topics: Buprenorphine; Cyanogen Bromide; Green Chemistry Technology; Methylation; Nitrogen; Salts; Thebaine

To investigate possible pharmacological mechanisms underlying the antinociceptive effect of and tolerance to N-methyl-7α-[(R)-1-hydroxy-1-methyl-3-(thien-3-yl)-propyl]-6,14-endo-ethanotetrahydronororipavine (030418), a derivative of thienorphine.. The binding affinity and efficacy of 030418 were determined using receptor binding and guanosine 5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPγS) assays in CHO-μ, CHO-κ, CHO-δ, and CHO-ORL1 cell membranes. The analgesic activity of and tolerance to 030418 were evaluated in thermal nociceptive tests in mice. The effects of 030418 on opioid receptors were further investigated using in vivo pharmacological antagonist blockade and in vitro tissue preparations.. The compound 030418 displayed high binding affinity to all subtypes of opioid receptors with K(i) values in the nanomolar range. In [(35)S]GTPγS binding assay, the maximal stimulation of 030418 to μ-, κ-, δ-receptors and the ORL1 receptor was 89%, 86%, 67% and 91%, respectively. In hot-plate test, the antinociceptive effect of 030418 was more potent and longer than morphine. The nonselective opioid receptor antagonist naloxone could completely block 030418-induced antinociception, while both the μ-opioid receptor antagonist β-FNA and the κ-opioid receptor antagonist nor-BNI attenuated 030418-induced antinociception. In contrast, the ORL1 receptor antagonist J-113397 enhanced the antinociceptive effect of 030418. Additionally, chronic treatment with 030418 resulted in a dramatic development of tolerance that could not be effectively prevented by J-113397. In guinea pig ileum preparation, the existing action of 030418 could be removed with difficulty after prolonged washing.. The compound 030418 is a novel agonist of opioid receptors with high efficiency, long-lasting effect and liability to tolerance, which may be closely correlated with the methyl group at the N(17) position and the high hydrophobicity of the C(7)-thiophene group in its chemical structure.

Topics: Analgesics; Animals; Buprenorphine; CHO Cells; Cricetinae; Drug Tolerance; Female; Guinea Pigs; Male; Mice; Nociception; Pain Measurement; Receptors, Opioid; Thebaine

This report presents the recommendations of a WHO Expert Committee responsible for reviewing information on dependence-producing drugs to assess the need for their international control. The first part of the report contains a summary of the Committee's evaluations of seven substances (dronabinol, oripavine, buprenorphine, butorphanol, ketamine, khat and zopiclone). The report also discusses the substances that were pre-reviewed (gamma-hydroxybutyric acid and tramadol) and recommended gamma-hydroxybutyric acid for critical review at a future meeting. Two substances (gamma-butyrolactone and 1,4-butanediol) were identified for future pre-review). The second part of the report discusses the guidelines for the WHO review of dependence-producing psychoactive substances for international control. It includes sections on amending the current guidelines, interpretation of specific aspects of the guidelines and access to information necessary for the evaluation of substances. The final section considers other matters including activities of the EMCCDA, the use of pharmacovigilance data, promotion of education and information on the appropriate use of psychoactive drugs and the impact of international control on medical availability of substances.

Topics: 4-Butyrolactone; Advisory Committees; Azabicyclo Compounds; Buprenorphine; Butorphanol; Catha; Dronabinol; Drug and Narcotic Control; Drug Evaluation; Health Services Accessibility; Humans; Hydroxybutyrates; Ketamine; Piperazines; Psychotropic Drugs; Substance-Related Disorders; Thebaine; Tramadol; World Health Organization

This study examines the possibility that oripavine opioid receptor agonists bind equally to both high and low affinity states of the mu-opioid receptor. Studies were performed in C6 cells expressing mu- or delta-opioid receptors; high and low agonist affinity states of the receptors were defined by the absence and presence, respectively of Na+ ions and the GTP analog Gpp(NH)p. At the mu-opioid receptor dihydroetorphine and etorphine were full agonists, buprenorphine had moderate efficacy while diprenorphine was an antagonist. At the delta-opioid receptor, dihydroetorphine, etorphine, and diprenorphine had moderate efficacy while buprenorphine was an antagonist. The binding affinities of the oripavines at the mu-opioid receptor decreased only one to 2-fold in the presence of NaCl and Gpp(NH)p. In contrast, decreases in oripavine affinity at the delta-opioid receptor correlated with delta-opioid receptor efficacy. The ability of oripavine agonists to bind with high affinity to the low agonist affinity state of the nu-opioid receptor may explain the high potencies of these compounds in vivo.

Topics: Analgesics, Opioid; Animals; Benzamides; Binding, Competitive; Buprenorphine; Cloning, Molecular; Diprenorphine; Dose-Response Relationship, Drug; Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; Etorphine; Fentanyl; Guanosine 5'-O-(3-Thiotriphosphate); Morphine; Naloxone; Piperazines; Radioligand Assay; Rats; Receptors, Opioid, delta; Receptors, Opioid, mu; Sulfur Radioisotopes; Thebaine; Tritium; Tumor Cells, Cultured

The relative in vivo receptor affinities of three oripavine drugs given subcutaneously were determined at the mu, delta and kappa type of opiate binding sites in rat brain. The oripavines include the agonist etorphine, the antagonist diprenorphine and the mixed agonist-antagonist buprenorphine. With the use of mu, delta and kappa specific labeling conditions in brain homogenates immediately after sacrifice (ex vivo labeling), the method relies on the assay of those receptor sites that remain unbound in vivo. Because of the slow receptor binding kinetics of the oripavines, little or no dissociation of the in vivo ligand occurs during the ex vivo labeling period. All three drugs displayed lower affinity in vivo at the delta sites relative to mu sites, whereas the kappa affinities were highly variable. Etorphine displayed considerable mu selectivity, while burpenorphine's affinity at the mu and kappa sites was similar. The apparent in vivo binding affinities obtained from the ex vivo labeling approach are compatible with previous results where tracers were applied in vivo. The dramatic differences of the in vivo and in vitro opiate receptor binding properties of the oripavines demonstrate the need for in vivo receptor binding parameters in the analysis of the function of individual receptor types.

Topics: Animals; Brain; Buprenorphine; Diprenorphine; Etorphine; Kinetics; Male; Morphinans; Rats; Rats, Inbred Strains; Receptors, Opioid; Receptors, Opioid, delta; Receptors, Opioid, kappa; Receptors, Opioid, mu; Thebaine

Buprenorphine (I), a member of the 6,14-endo-ethanotetrahydrooripavine series of analgesics, undergoes an acid-catalyzed rearrangement reaction when exposed to acid and heat. The product was shown by 1H-NMR and GC-MS to have undergone overall elimination of a molecule of methanol with concurrent formation of a tetrahydrofuran ring at C(6)-C(7) of I. Short-term stability studies across a wide range of pH and temperature conditions indicate that I is stable in aqueous solution at pH greater than 3 for 24 h at 36-38 degrees C. Under the more extreme conditions of the autoclave, significant loss of I occurred. Long-term stability studies (10 weeks) of I in aqueous solution (pH 1 and pH 5) at 0-4 degrees C and 26-28 degrees C indicate only minor conversion (4%) to the rearrangement product. Eight other 6,14-endo-ethanotetrahydrooripavine derivatives were subjected to extremes of acid (pH 0) and temperature (autoclave) to determine if similar rearrangement reactions occur. GC-MS indicated that hydrolysis products were produced whose spectra were consistent with the proposed rearrangement structures.

Topics: Analgesics; Buprenorphine; Catalysis; Drug Stability; Hydrogen-Ion Concentration; Hydrolysis; Morphinans; Thebaine