gamma-Butyrolactone

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gamma-Butyrolactone[1][2]
Gamma-Butyrolactone.svg
GBL-from-xtal-3D-balls.png
Identifiers
CAS number 96-48-0 YesY
PubChem 7302
ChemSpider 7029 YesY
UNII OL659KIY4X YesY
DrugBank DB04699
KEGG C01770 YesY
ChEBI CHEBI:42639 YesY
ChEMBL CHEMBL95681 YesY
RTECS number LU3500000
Jmol-3D images Image 1
Properties
Molecular formula C4H6O2
Molar mass 86.09 g mol−1
Appearance Colorless oily liquid
Density 1.1286 g/mL (15 °C), 1.1296 g/mL (20 °C)
Melting point −43.53 °C (−46.35 °F; 229.62 K)
Boiling point 204 °C (399 °F; 477 K)
Solubility in water Miscible
Solubility soluble in CCl4, methanol, ethanol, acetone, benzene, ethyl ether
Acidity (pKa) 4.5
Refractive index (nD) 1.435, 1.4341 (20 °C)
Viscosity 1.7 cp (25 °C)
Hazards
R-phrases R22 R36
S-phrases S26 S36
Main hazards Harmful
Flash point 98 °C (closed cup)
LD50 17.2 mL/kg (orally, rat)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

gamma-Butyrolactone (γ-butyrolactone or GBL) is a hygroscopic colorless oily liquid with a weak characteristic odor and is soluble in water. GBL is a common solvent and reagent in chemistry and is used as an flavouring, as a stain remover, as a wheel cleaner, as a superglue remover, as a paint stripper, and as a solvent in some wet aluminium electrolytic capacitors. In humans it acts as a prodrug for GHB, and it is used as a recreational intoxicant with effects similar to alcohol.

Occurrence[edit]

GBL has been found in extracts from samples of unadulterated wines.[3] This finding indicates that GBL is a naturally occurring component in some wines and may be present in similar products. The concentration detected was approximately 5 μg/mL and was easily observed using a simple extraction technique followed by GC/MS analysis. GBL can be found in cheese flavourings but typically results in a content of 0.0002% GBL in the final foodstuff.[4]

Preparation[edit]

GBL can be synthesized by the dehydration of gamma-hydroxybutyric acid (GHB), this can be achieved by distillation.

Synthesis gamma-Butyrolactone.svg

It may also be obtained via the oxidation of tetrahydrofuran (THF), for example with aqueous bromine.[5]

Chemistry[edit]

GBL is a lactone. It is hydrolyzed under basic conditions, for example in a sodium hydroxide solution into sodium gamma-hydroxybutyrate, the sodium salt of gamma-hydroxybutyric acid. Under acidic conditions it forms an equilibrium mixture of both compounds. These compounds then may go on to form a polymer. When treated with a non-nucleophilic base, like lithium diisopropylamide, GBL can become an alpha-carbon nucleophile. Related compound caprolactone can be used to make a polyester in this manner.

Pharmacology[edit]

GBL is not active in its own right; its mechanism of action stems from its identity as a prodrug of GHB.

The hypnotic effect of GHB is enhanced by combination with alcohol. A 2003 rat study showed that GBL in combination with ethanol showed a potentiated hypnotic effect, as the sleep-timing measure was longer than both of the individual components combined.[6]

Pharmacokinetics[edit]

GBL is rapidly converted into GHB by lactonase enzymes found in the blood. GBL is more lipophilic (fat soluble) than GHB, and so is absorbed faster and has higher bioavailability; the paradox is that this can mean that GBL has a faster onset of effects than GHB itself, even though it is a prodrug. The levels of lactonase enzyme can vary between individuals, meaning that first-time users can show unpredictable results, even from small doses. In many this manifests as slow onset of effects, followed by headaches, semi-consciousness which is distinct from GBL sleep in normal users. If the user decides to try again at a later date, they appear to be able to enjoy the effects normally. Because of these pharmacokinetic differences, GBL tends to be more potent and faster-acting than GHB, but has a shorter duration; whereas the related compound 1,4-butanediol (1,4-B) tends to be slightly less potent, slower to take effect but longer-acting than GHB.

Metabolic pathway of 1,4-butanediol, GBL and GHB.

Use as a nutritional supplement[edit]

Due to its property of being a prodrug of GHB which increases sleep related growth hormone (GH) secretion,[7] GBL was sold as a nutritional supplement after the scheduling of GHB, under the names Revivarant and Renewtrient[8] in the U.S. at least until the end of 1999.[citation needed]

Recreational use[edit]

GBL is a prodrug of GHB. To bypass GHB restriction laws, home synthesis kits were introduced to transform GBL and/or 1,4-B into GHB. GBL can also be used as a recreational drug by itself.[9]

Jugs of seized GBL.
FDA warning against products containing GHB and its prodrugs, such as GBL.

GBL overdose can cause irrational behaviour, severe sickness, coma and death.[10]

Metabolism takes place in stomach and blood plasma. Both the duration and onset of GBL are shorter than of GHB. Otherwise, effects are similar to GHB, although weight for weight GBL is significantly more powerful due to being absorbed faster and its higher bioavailability, meaning dosage must be lowered accordingly. If taken undiluted by mouth, GBL can cause esophageal and gastro-intestinal irritation. It is possible for oral ingestion of GBL to cause nausea and other similar problems, possibly more so than with GHB.

Dangers[edit]

GHB (gamma hydroxybutyrate) and GBL (gamma butyrolactone) are substances which are often used as recreational drugs. GHB has two effects, at low doses it has a euphoric effect (which is why it is sometimes referred to as liquid ecstasy). GHB also has a sedative effect[11] and at higher doses it can cause unconsciousness.[12]

There have been news reports of several deaths associated with GBL.[13]

Addictiveness[edit]

Frequent use of GHB/GBL, even when taken long-term and in moderate doses, does not appear to cause significant physical dependency in the greater majority of its users. In many people, quitting or temporarily abstaining from use of the drugs is achieved with minimal or no difficulty. However, when consumed in excessive amounts with a high frequency of dosing, physical and psychological dependence can develop.[14][15]

There are some reports of GHB/GBL users adopting a '24/7' dosing regime.[16] This is where the user has become tolerant to the effects of the drug, increasing the dosage and frequency of dosage simply to avoid withdrawal symptoms.

For those users who do report withdrawal symptoms upon quitting the use of GHB/GBL, symptoms seem to depend on the dosage and the length of time the drug was used for. Light to moderate users often experience insomnia and sleep-related problems, whereas heavy, prolonged use can cause severe withdrawal symptoms similar to Benzodiazepine withdrawal syndrome (BWS).

Dose[edit]

A milliliter of pure GBL metabolizes to the equivalent 1.65g of NaGHB, the common form, so doses are measured in the single milliliter range, either taken all at once or sipped over the course of a night. GBL has a distinctive taste and odour, described as being comparable to stale water, synthetic melon aroma or burnt plastic. This differs significantly from GHB, which is described as having a decidedly "salty" taste.[17]

Legal status of GBL[edit]

Australia: GBL is a border controlled substance and is illegal to import into Australia without a permit. The importation of a commercial quantity of a border controlled drug (over 1 kg of GBL) is punishable by up to life imprisonment and/or an $825,000 fine.[18]

Canada: GBL is a Controlled Substance under Schedule VI of the "Controlled Drugs and Substances Act" in Canada. Schedule VI of the "Controlled Drugs and Substances Act" requires vendors to collect information regarding purchases of GBL. The Act also prohibits the import and export of GBL into or out of Canada classifying it as either an indictable offense punishable with up to 10 years in prison or an offense punishable on summary conviction liable to imprisonment for up to eighteen months.[19] It is not illegal for an individual to possess GBL in Canada.[citation needed]

Germany: GBL is not listed in the narcotics law, but its distribution is controlled. Possession is not illegal, but may be punished according to the Medicines Act, when intended to be sold for human consumption or synthesis of GHB. In recent years, an increase of GBL consumption has been observed due to the prohibition of GHB.

Hong Kong SAR: GBL is a dangerous drug controlled under Schedule 1 of the Dangerous Drugs Ordinance, Cap.134 (with exemption clause at Paragraph 16D). Any person who is found to have in his possession of it not in accordance with this Ordinance can be liable, on conviction upon indictment, a fine of HK$1,000,000 and to imprisonment for 7 years.

Israel: GBL was classified as a proscribed substance from 2007.[20]

The Netherlands: GBL can be freely bought as a cleaning agent. Retailers do not need a licence to sell the substance.[21]

Poland: GBL is not classified as a drug and can be purchased in chemistry shops as a solvent.

Sweden: GBL is not classified as a drug but as a health-endangering substance. Although recently passed legislation to enter into force on 1 April 2011 will make it possible to handle narcotics for industrial purposes will enable GBL and 1,4-Butanediol to be classified as controlled substances.[22]

United Kingdom: Because of their legitimate uses, regulation 4B of the 2001 regulations makes it lawful to import, export, produce, supply, offer to supply or possess GBL and 1,4-BD. Except where a person does so knowing or believing that they will be used for the purpose of human ingestion.[4][23]

United States: GBL is regulated as a List 1 controlled chemical. As a GHB analog, it is treated as a controlled substance under Schedule I of the "Controlled Substances Act" if intended for human consumption.[24]

See also[edit]

References[edit]

  1. ^ Merck Index, 12th Edition, 1632.
  2. ^ Lide, David R., ed. (2009-06-03). CRC Handbook of Chemistry and Physics (90th ed.). Boca Raton, Florida: CRC Press. ISBN 1-4200-9084-4. Retrieved 2011-07-18. 
  3. ^ Vose, J.; Tighe, T.; Schwartz, M.; Buel, E. (2001). "Detection of gamma-butyrolactone (GBL) as a natural component in wine". Journal of forensic sciences 46 (5): 1164–1167. PMID 11569560.  edit
  4. ^ a b http://www.gov.uk/government/uploads/system/uploads/attachment_data/file/100526/21-2009.pdf
  5. ^ Metsger, Leonid; Bittner, Shmuel (March 2000). "Autocatalytic Oxidation of Ethers with Sodium Bromate". Tetrahedron 56 (13): 1905–1910. doi:10.1016/S0040-4020(00)00098-3. 
  6. ^ Van Sassenbroeck, D. K.; De Paepe, P.; Belpaire, F. M.; Buylaert, W. A. (2003). "Characterization of the Pharmacokinetic and Pharmacodynamic Interaction between Gamma-Hydroxybutyrate and Ethanol in the Rat". Toxicological Sciences 73 (2): 270–278. doi:10.1093/toxsci/kfg079. PMID 12700396.  edit
  7. ^ Van Cauter, E.; Plat, L.; Scharf, M. B.; Leproult, R.; Cespedes, S.; l'Hermite-Balériaux, M.; Copinschi, G. (1997). "Simultaneous stimulation of slow-wave sleep and growth hormone secretion by gamma-hydroxybutyrate in normal young Men". Journal of Clinical Investigation 100 (3): 745–753. doi:10.1172/JCI119587. PMC 508244. PMID 9239423.  edit
  8. ^ "Erowid GHB vault: FDA Warning about Gamma Butyrlactone". Erowid. 1998-11-21. Retrieved 2013-10-10. 
  9. ^ Meyer, Jerrold; Linda F. Quenzer (2005). Psychopharmacology: Drugs, the Brain and Behavior. Sinauer. p. 370. ISBN 0-87893-534-7. 
  10. ^ "USDOJ: U.S. Department of Justice Archive National Drug Intelligence Center". Usdoj.gov. 2012-06-15. Retrieved 2014-01-22. 
  11. ^ van Nieuwenhuijzen, PS; McGregor, IS (Aug 1, 2009). "Sedative and hypothermic effects of gamma-hydroxybutyrate (GHB) in rats alone and in combination with other drugs: assessment using biotelemetry.". Drug and alcohol dependence 103 (3): 137–47. doi:10.1016/j.drugalcdep.2009.03.004. PMID 19446408. 
  12. ^ Edwards, Richard (23 July 2009). "Coroner's 'Russian roulette' warning over GBL party drug". The Telegraph. The Telegraph. Retrieved May 1, 2012. 
  13. ^ Casciani, Dominic (23 December 2009). "GBL drug death identified by UK doctors". BBC News. Retrieved May 1, 2012. 
  14. ^ GHB addiction, GHB physical n psychological dependancy levels
  15. ^ ADANZ - ghb
  16. ^ Crew 2000 | GHB/ GBL Dependancy | | Drugs information, advice & support, Scotland, UK
  17. ^ Galloway, G. P.; Frederick-Osborne, S. L.; Seymour, R.; Contini, S. E.; Smith, D. E. (2000). "Abuse and therapeutic potential of gamma-hydroxybutyric acid". Alcohol 20 (3): 263–269. doi:10.1016/S0741-8329(99)00090-7. PMID 10869868.  edit
  18. ^ LAW AND JUSTICE LEGISLATION AMENDMENT (SERIOUS DRUG OFFENCES AND OTHER MEASURES) ACT 2005 NO. 129, 2005 - SCHEDULE 1 http://www.austlii.edu.au/au/legis/cth/num_act/lajladoaoma2005722/sch1.html
  19. ^ Controlled Drugs and Substances Act (S.C. 1996, c. 19) http://laws-lois.justice.gc.ca/eng/acts/C-38.8/page-3.html
  20. ^ section 7c of chapter B of part A of the 1st appendix of the Dangerous Drugs Act 1973 http://www.nevo.co.il/Law_word/law01/P170_001.doc
  21. ^ "Verkopers schoonmaakmiddel verdienen fors aan partydrug GHB". Trouw (in Dutch). 11 April 2012. Retrieved 11 April 2012. 
  22. ^ Socialutskottets betänkande 2010/11:SoU5 - Riksdagen
  23. ^ "UK Statutory Instrument 2011 No. 448". 2011-02-18. 
  24. ^ Information Bulletin: GHB Analogs; GBL, BD, GHV, and GVL

External links[edit]