Hydromorphone (T3D2752)

IdentificationTaxonomyBiological PropertiesPhysical PropertiesToxicity ProfileSpectraConcentrationsLinksReferencesGene RegulationTargets (3)XML
Targets (3)
Record Information
Version2.0
Creation Date2009-07-21 20:26:36 UTC
Update Date2014-12-24 20:25:51 UTC
Accession NumberT3D2752
Identification
Common NameHydromorphone
ClassSmall Molecule
DescriptionHydromorphone is only found in individuals that have used or taken this drug. It is an opioid analgesic derived from morphine and used mainly as an analgesic. It has a shorter duration of action and is more potent than morphine. Hydromorphone is a narcotic analgesic; its principal therapeutic effect is relief of pain. Hydromorphone interacts predominantly with the opioid mu-receptors. These mu-binding sites are discretely distributed in the human brain, with high densities in the posterior amygdala, hypothalamus, thalamus, nucleus caudatus, putamen, and certain cortical areas. They are also found on the terminal axons of primary afferents within laminae I and II (substantia gelatinosa) of the spinal cord and in the spinal nucleus of the trigeminal nerve. In clinical settings, Hydromorphone exerts its principal pharmacological effect on the central nervous system and gastrointestinal tract. Hydromorphone also binds with kappa-receptors which are thought to mediate spinal analgesia, miosis and sedation.
Compound Type
  • Amine
  • Analgesic, Opioid
  • Drug
  • Ether
  • Metabolite
  • Narcotic
  • Organic Compound
  • Synthetic Compound
Chemical Structure
Thumb
MOLSDFPDBSMILESInChI
Synonyms
Synonym
(-)-(5R)-4,5-Epoxy-3-hydroxy-9alpha-methylmorphinan-6-one
4,5-Epoxy-3-hydroxy-17-methylmorphinan-6-one
4,5alpha-Epoxy-3-hydroxy-17-methyl-6-morphinanone
6-Deoxy-7,8-dihydro-6-oxomorphine
7,8-Dihydromorphinone
Dihydromorfinon
Dihydromorphinone
Dilaudid
Dimorphone
EXALGO
Hidromorfona
Hydromorfona
Hydromorphon
Hydromorphonum
Idromorfone
Palladone
Chemical FormulaC17H19NO3
Average Molecular Mass285.338 g/mol
Monoisotopic Mass285.136 g/mol
CAS Registry Number466-99-9
IUPAC Name(1S,5R,13R,17R)-10-hydroxy-4-methyl-12-oxa-4-azapentacyclo[9.6.1.0¹,¹³.0⁵,¹⁷.0⁷,¹⁸]octadeca-7(18),8,10-trien-14-one
Traditional Namehydromorphone
SMILES[H][C@@]12OC3=C(O)C=CC4=C3[C@@]11CCN(C)[C@]([H])(C4)[C@]1([H])CCC2=O
InChI IdentifierInChI=1S/C17H19NO3/c1-18-7-6-17-10-3-5-13(20)16(17)21-15-12(19)4-2-9(14(15)17)8-11(10)18/h2,4,10-11,16,19H,3,5-8H2,1H3/t10-,11+,16-,17-/m0/s1
InChI KeyInChIKey=WVLOADHCBXTIJK-YNHQPCIGSA-N
Chemical Taxonomy
Description belongs to the class of organic compounds known as morphinans. These are polycyclic compounds with a four-ring skeleton with three condensed six-member rings forming a partially hydrogenated phenanthrene moiety, one of which is aromatic while the two others are alicyclic.
KingdomOrganic compounds
Super ClassAlkaloids and derivatives
ClassMorphinans
Sub ClassNot Available
Direct ParentMorphinans
Alternative Parents
Substituents
  • Morphinan
  • Phenanthrene
  • Isoquinolone
  • Tetralin
  • Coumaran
  • Alkyl aryl ether
  • 1-hydroxy-2-unsubstituted benzenoid
  • Aralkylamine
  • Piperidine
  • Benzenoid
  • Ketone
  • Tertiary amine
  • Tertiary aliphatic amine
  • Oxacycle
  • Ether
  • Azacycle
  • Organoheterocyclic compound
  • Amine
  • Hydrocarbon derivative
  • Organic oxide
  • Organooxygen compound
  • Organonitrogen compound
  • Organopnictogen compound
  • Organic nitrogen compound
  • Organic oxygen compound
  • Carbonyl group
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginExogenous
Cellular Locations
  • Cytoplasm
  • Extracellular
  • Membrane
Biofluid LocationsNot Available
Tissue LocationsNot Available
PathwaysNot Available
Applications
Biological Roles
Chemical RolesNot Available
Physical Properties
StateSolid
AppearanceWhite powder.
Experimental Properties
PropertyValue
Melting Point266.5°C
Boiling PointNot Available
Solubility4.39e+00 g/L
LogP0.9
Predicted Properties
PropertyValueSource
Water Solubility4.39 g/LALOGPS
logP1.69ALOGPS
logP1.62ChemAxon
logS-1.8ALOGPS
pKa (Strongest Acidic)10.11ChemAxon
pKa (Strongest Basic)8.59ChemAxon
Physiological Charge1ChemAxon
Hydrogen Acceptor Count4ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area49.77 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity78.26 m³·mol⁻¹ChemAxon
Polarizability30.02 ųChemAxon
Number of Rings5ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Spectra
Spectrum TypeDescriptionSplash KeyDeposition DateView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-0adl-2090000000-1b72d2e162be578cb94d2017-09-01View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (1 TMS) - 70eV, Positivesplash10-006x-6039000000-d29846cb85959ad1cc2c2017-10-06View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, PositiveNot Available2021-10-12View Spectrum
LC-MS/MSLC-MS/MS Spectrum - 35V, Positivesplash10-000i-0290000000-0c258477ac267eb9243c2021-09-20View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-000i-0090000000-052fc44835772dd50b652016-06-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-000i-0090000000-711917845b2129c2d3e32016-06-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0a4l-7090000000-8d20bdd275a62a96fd872016-06-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-001i-0090000000-a0979bf03853322bb9f72016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-001i-0090000000-2cd300544d508b429bee2016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-00ou-1290000000-c40fe8399a0aae44bc332016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-000i-0090000000-12d6d7cf9e71a6a9ec092021-09-25View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-000i-0090000000-94ce4b4a1e2ea08a7fc92021-09-25View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0006-2090000000-aa4c1402684fd83597292021-09-25View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-001i-0090000000-793f02ff50658d83401d2021-09-25View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-001i-0090000000-c9bb75a9e6ed1373a7302021-09-25View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-001i-0090000000-4e4413edce04e0b80bd62021-09-25View Spectrum
MSMass Spectrum (Electron Ionization)splash10-002r-6960000000-9f3d9b17d56e032d76c52014-09-20View Spectrum
1D NMR13C NMR Spectrum (1D, 100 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 100 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR13C NMR Spectrum (1D, 1000 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 1000 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR13C NMR Spectrum (1D, 200 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 200 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR13C NMR Spectrum (1D, 300 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 300 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR13C NMR Spectrum (1D, 400 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 400 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR13C NMR Spectrum (1D, 500 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 500 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR13C NMR Spectrum (1D, 600 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 600 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR13C NMR Spectrum (1D, 700 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 700 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR13C NMR Spectrum (1D, 800 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 800 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR13C NMR Spectrum (1D, 900 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
1D NMR1H NMR Spectrum (1D, 900 MHz, D2O, predicted)Not Available2021-09-29View Spectrum
Toxicity Profile
Route of ExposureParental (intravenous, intramuscular); oral; enteral(rectal). Better absorbed orally than morphine.
Mechanism of ToxicityHydromorphone is a narcotic analgesic; its principal therapeutic effect is relief of pain. Hydromorphone interacts predominantly with the opioid mu-receptors. These mu-binding sites are discretely distributed in the human brain, with high densities in the posterior amygdala, hypothalamus, thalamus, nucleus caudatus, putamen, and certain cortical areas. They are also found on the terminal axons of primary afferents within laminae I and II (substantia gelatinosa) of the spinal cord and in the spinal nucleus of the trigeminal nerve. In clinical settings, Hydromorphone exerts its principal pharmacological effect on the central nervous system and gastrointestinal tract. Hydromorphone also binds with kappa-receptors which are thought to mediate spinal analgesia, miosis and sedation.
MetabolismPrimarily hepatic. After absorption hydromorphone is metabolized by the liver to the glucuronide conjugate which is then excreted in the urine. Hydromorphone is metabolized to the major metabolites hydromorphone-3-glucuronide, hydromorphone-3-glucoside and dihydroisomorphine-6-glucuronide. Route of Elimination: Only a small amount of the hydromorphone dose is excreted unchanged in the urine. Most of the dose is excreted as hydromorphone-3-glucuronide along with minor amounts of 6-hydroxy reduction metabolites. Half Life: 2.6 hours (oral); 18.6 hours for sustained release Palladone
Toxicity ValuesNot Available
Lethal DoseNot Available
Carcinogenicity (IARC Classification)No indication of carcinogenicity to humans (not listed by IARC).
Uses/SourcesFor the relief of moderate to severe pain such as that due to surgery, cancer, trauma/injury, or burns.
Minimum Risk LevelNot Available
Health EffectsMedical problems can include congested lungs, liver disease, tetanus, infection of the heart valves, skin abscesses, anemia and pneumonia. Death can occur from overdose.
SymptomsHydromorphone is a schedule II narcotic which can lead to physical dependence or addiction. High doses lead to respiratory depression, nausea, and vomiting. Overdoses lead to extreme somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, and sometimes bradycardia and hypotension. In severe overdosage, apnea, circulatory collapse, cardiac arrest and death may occur.
TreatmentIn the treatment of overdosage, primary attention should be given to the reestablishment of adequate respiratory exchange through provision of a patent airway and institution of assisted or controlled ventilation. A potentially serious oral ingestion, if recent, should be managed with gut decontamination. In unconscious patients with a secure airway, instill activated charcoal (30-100 g in adults, 1-2 g/kg in infants) via a nasogastric tube. A saline cathartic or sorbitol may be added to the first dose of activated charcoal. Supportive measures (including oxygen, vasopressors) should be employed in the management of circulatory shock and pulmonary edema accompanying overdose as indicated. Cardiac arrest or arrhythmias may require cardiac massage or defibrillation. The opioid antagonist, naloxone, is a specific antidote against respiratory depression which may result from overdosage, or unusual sensitivity to Hydromorphone. Therefore, an appropriate dose of this antagonist should be administered, preferably by the intravenous route, simultaneously with efforts at respiratory resuscitation. Naloxone should not be administered in the absence of clinically significant respiratory or circulatory depression. (5)
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
DrugBank IDDB00327
HMDB IDHMDB14472
PubChem Compound ID5284570
ChEMBL IDCHEMBL398707
ChemSpider ID4447624
KEGG IDC07042
UniProt IDNot Available
OMIM ID
ChEBI ID5790
BioCyc IDNot Available
CTD IDNot Available
Stitch IDHydromorphone
PDB IDNot Available
ACToR IDNot Available
Wikipedia LinkHydromorphone
References
Synthesis Reference

Anne M. Hailes, Christopher E. French, Neil C. Bruce, “Morphinone reductase for the preparation of hydromorphone and hydrocodone.” U.S. Patent US5571685, issued November, 1990.

MSDSLink
General References
  1. Coda BA, Rudy AC, Archer SM, Wermeling DP: Pharmacokinetics and bioavailability of single-dose intranasal hydromorphone hydrochloride in healthy volunteers. Anesth Analg. 2003 Jul;97(1):117-23, table of contents. [12818953 ]
  2. Vallner JJ, Stewart JT, Kotzan JA, Kirsten EB, Honigberg IL: Pharmacokinetics and bioavailability of hydromorphone following intravenous and oral administration to human subjects. J Clin Pharmacol. 1981 Apr;21(4):152-6. [6165742 ]
  3. Drugs.com [Link]
  4. Drugs.com [Link]
  5. RxList: The Internet Drug Index (2009). [Link]
Gene Regulation
Up-Regulated GenesNot Available
Down-Regulated GenesNot Available

Targets

Target Details
1. Mu-type opioid receptor
General Function:
Voltage-gated calcium channel activity
Specific Function:
Receptor for endogenous opioids such as beta-endorphin and endomorphin. Receptor for natural and synthetic opioids including morphine, heroin, DAMGO, fentanyl, etorphine, buprenorphin and methadone. Agonist binding to the receptor induces coupling to an inactive GDP-bound heterotrimeric G-protein complex and subsequent exchange of GDP for GTP in the G-protein alpha subunit leading to dissociation of the G-protein complex with the free GTP-bound G-protein alpha and the G-protein beta-gamma dimer activating downstream cellular effectors. The agonist- and cell type-specific activity is predominantly coupled to pertussis toxin-sensitive G(i) and G(o) G alpha proteins, GNAI1, GNAI2, GNAI3 and GNAO1 isoforms Alpha-1 and Alpha-2, and to a lesser extend to pertussis toxin-insensitive G alpha proteins GNAZ and GNA15. They mediate an array of downstream cellular responses, including inhibition of adenylate cyclase activity and both N-type and L-type calcium channels, activation of inward rectifying potassium channels, mitogen-activated protein kinase (MAPK), phospholipase C (PLC), phosphoinositide/protein kinase (PKC), phosphoinositide 3-kinase (PI3K) and regulation of NF-kappa-B. Also couples to adenylate cyclase stimulatory G alpha proteins. The selective temporal coupling to G-proteins and subsequent signaling can be regulated by RGSZ proteins, such as RGS9, RGS17 and RGS4. Phosphorylation by members of the GPRK subfamily of Ser/Thr protein kinases and association with beta-arrestins is involved in short-term receptor desensitization. Beta-arrestins associate with the GPRK-phosphorylated receptor and uncouple it from the G-protein thus terminating signal transduction. The phosphorylated receptor is internalized through endocytosis via clathrin-coated pits which involves beta-arrestins. The activation of the ERK pathway occurs either in a G-protein-dependent or a beta-arrestin-dependent manner and is regulated by agonist-specific receptor phosphorylation. Acts as a class A G-protein coupled receptor (GPCR) which dissociates from beta-arrestin at or near the plasma membrane and undergoes rapid recycling. Receptor down-regulation pathways are varying with the agonist and occur dependent or independent of G-protein coupling. Endogenous ligands induce rapid desensitization, endocytosis and recycling whereas morphine induces only low desensitization and endocytosis. Heterooligomerization with other GPCRs can modulate agonist binding, signaling and trafficking properties. Involved in neurogenesis. Isoform 12 couples to GNAS and is proposed to be involved in excitatory effects. Isoform 16 and isoform 17 do not bind agonists but may act through oligomerization with binding-competent OPRM1 isoforms and reduce their ligand binding activity.
Gene Name:
OPRM1
Uniprot ID:
P35372
Molecular Weight:
44778.855 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
Inhibitory0.00028 uMNot AvailableBindingDB 50241341
References
  1. Jiang Q, Sebastian A, Archer S, Bidlack JM: 5 beta-Methyl-14 beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone: a long-lasting mu-opioid receptor antagonist devoid of agonist properties. Eur J Pharmacol. 1993 Jan 5;230(1):129-30. [7679076 ]
  2. Quigley C: Hydromorphone for acute and chronic pain. Cochrane Database Syst Rev. 2002;(1):CD003447. [11869661 ]
  3. Winslow M, Ng WL, Mythily S, Song G, Yiong HC: Socio-demographic profile and help-seeking behaviour of buprenorphine abusers in Singapore. Ann Acad Med Singapore. 2006 Jul;35(7):451-6. [16902719 ]
  4. Kogel B, Christoph T, Strassburger W, Friderichs E: Interaction of mu-opioid receptor agonists and antagonists with the analgesic effect of buprenorphine in mice. Eur J Pain. 2005 Oct;9(5):599-611. [16139189 ]
  5. Greenwald MK, Johanson CE, Moody DE, Woods JH, Kilbourn MR, Koeppe RA, Schuster CR, Zubieta JK: Effects of buprenorphine maintenance dose on mu-opioid receptor availability, plasma concentrations, and antagonist blockade in heroin-dependent volunteers. Neuropsychopharmacology. 2003 Nov;28(11):2000-9. [12902992 ]
  6. Wentland MP, Lou R, Lu Q, Bu Y, Denhardt C, Jin J, Ganorkar R, VanAlstine MA, Guo C, Cohen DJ, Bidlack JM: Syntheses of novel high affinity ligands for opioid receptors. Bioorg Med Chem Lett. 2009 Apr 15;19(8):2289-94. doi: 10.1016/j.bmcl.2009.02.078. Epub 2009 Feb 25. [19282177 ]
Target Details
2. Delta-type opioid receptor
General Function:
Opioid receptor activity
Specific Function:
G-protein coupled receptor that functions as receptor for endogenous enkephalins and for a subset of other opioids. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors, such as adenylate cyclase. Signaling leads to the inhibition of adenylate cyclase activity. Inhibits neurotransmitter release by reducing calcium ion currents and increasing potassium ion conductance. Plays a role in the perception of pain and in opiate-mediated analgesia. Plays a role in developing analgesic tolerance to morphine.
Gene Name:
OPRD1
Uniprot ID:
P41143
Molecular Weight:
40368.235 Da
References
  1. Fang X, Larson DL, Portoghese PS: 7-spirobenzocyclohexyl derivatives of naltrexone, oxymorphone, and hydromorphone as selective opioid receptor ligands. J Med Chem. 1997 Sep 12;40(19):3064-70. [9301669 ]
  2. Hennies HH, Friderichs E, Schneider J: Receptor binding, analgesic and antitussive potency of tramadol and other selected opioids. Arzneimittelforschung. 1988 Jul;38(7):877-80. [2849950 ]
  3. Jiang Q, Sebastian A, Archer S, Bidlack JM: 5 beta-Methyl-14 beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone and its corresponding N-cyclopropylmethyl analog, N-cyclopropylmethylnor-5 beta-methyl-14 beta-(p-nitrocinnamoylamino)- 7,8-dihydromorphinone: mu-selective irreversible opioid antagonists. J Pharmacol Exp Ther. 1994 Mar;268(3):1107-13. [7511163 ]
  4. Guay DR: Use of oral oxymorphone in the elderly. Consult Pharm. 2007 May;22(5):417-30. [17658959 ]
  5. Hartvig P, Neil A, Terenius L, Antoni G, Rimland A, Ulin J, Langstrom B: Brain and plasma kinetics of the opioid 11C-hydromorphone in two macaque species. Pharmacol Toxicol. 1989 Sep;65(3):214-6. [2478994 ]
Target Details
3. Kappa-type opioid receptor
General Function:
Opioid receptor activity
Specific Function:
G-protein coupled opioid receptor that functions as receptor for endogenous alpha-neoendorphins and dynorphins, but has low affinity for beta-endorphins. Also functions as receptor for various synthetic opioids and for the psychoactive diterpene salvinorin A. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors, such as adenylate cyclase. Signaling leads to the inhibition of adenylate cyclase activity. Inhibits neurotransmitter release by reducing calcium ion currents and increasing potassium ion conductance. Plays a role in the perception of pain. Plays a role in mediating reduced physical activity upon treatment with synthetic opioids. Plays a role in the regulation of salivation in response to synthetic opioids. May play a role in arousal and regulation of autonomic and neuroendocrine functions.
Gene Name:
OPRK1
Uniprot ID:
P41145
Molecular Weight:
42644.665 Da
Binding/Activity Constants
TypeValueAssay TypeAssay Source
Inhibitory0.0028 uMNot AvailableBindingDB 50241341
References
  1. Overington JP, Al-Lazikani B, Hopkins AL: How many drug targets are there? Nat Rev Drug Discov. 2006 Dec;5(12):993-6. [17139284 ]
  2. Imming P, Sinning C, Meyer A: Drugs, their targets and the nature and number of drug targets. Nat Rev Drug Discov. 2006 Oct;5(10):821-34. [17016423 ]
  3. Wentland MP, Lou R, Lu Q, Bu Y, Denhardt C, Jin J, Ganorkar R, VanAlstine MA, Guo C, Cohen DJ, Bidlack JM: Syntheses of novel high affinity ligands for opioid receptors. Bioorg Med Chem Lett. 2009 Apr 15;19(8):2289-94. doi: 10.1016/j.bmcl.2009.02.078. Epub 2009 Feb 25. [19282177 ]