[Ananthan S. (2006). Opioid ligands with mixed mu/delta opioid receptor interactions: an emerging approach to novel analgesics. AAPS J 8: E118-E125.]Search in Google Scholar
[Bagley JR, Kudzma LV, Lalinde NL, Colapret JA, Huang B-S, Lin B-S, Jerussi TP, Benvenga MJ, Doorley BM, Ossipov MH, Spaulding TC, Spencer HK, Rudo FG, Wynn RL. (1991). Evolution of the 4-anilidopiperidine class of opioid analgesics. Med Res Rev 11: 403-436.]Search in Google Scholar
[Bi-Yi C, Wen-Qiao J, Jie C, Xin-Jian C, You-Cheng Z, Zhi-Qiang C. (1999). Analgesic activity and selectivity of isothiocyanate derivatives of fentanyl analogs for opioid receptors. Life Sci 65: 1589-1595.]Search in Google Scholar
[Casy AF, Parfi tt RT. (1986). Opioid analgesics. Plennum NY Correa CR, Calixto JB. (1993). Evidence for participation of B1 and B2 kinin receptors in formalin-induced nociceptive response in the mouse. Br J Pharmacol 110: 193-198.]Search in Google Scholar
[Damas J, Liegeois JF. (1999). The infl ammatory reaction induced by formalin in the rat paw. Naunyn-Schmeidebergs Arch Pharmacol 359: 220-227.]Search in Google Scholar
[Dixon WJ. (1965). The up-and-down method for small samples. J Amer Statist Assoc 60: 967- 978.]Search in Google Scholar
[Feldman PL, James MK, Brackeen MF, Bilotta JM, Schuster SV, Lahey AP, Lutz MW, Johnson MR, Leighton HJ. (1991). Design, synthesis, and pharmacological evaluation of ultrashort- to long-acting opioid analgetics. J Med Chem 34: 2202-2208.]Search in Google Scholar
[Gardocki JF, Yelnosky J. (1964). A study of some of the pharmacological actions of fentanyl citrate. Toxicol Appl Pharmacol 6: 48-62.]Search in Google Scholar
[Gerak LR, Moerschbaecher JM, Bagley JR, Brockunier LL, France CP. (1999). Effects of a novel fentanyl derivative on drug discrimination and learning in rhesus monkeys. Pharmacol Biochem Behav 64: 367-371.]Search in Google Scholar
[Gupta PK, Yadav SK, Bhutia YD, Singh P, Rao P, Gujar NL, Ganesan K, Bhattacharya R. (2013). Synthesis and comparative bioeffi cacy of N-(1- phenethyl-4-piperidinyl)propionanilide (fentanyl) and its 1-substituted analogs in Swiss albino mice. Med Chem Res 22: 3888-3896.]Search in Google Scholar
[Hallenbeck JL. (2003). Palliative care perspective. Oxford University Press, Inc., New York Higashikawa Y, Suzuki S. (2008). Studies on 1-(2-phenethyl)-4-(N-propionylanilino) piperidine (fentanyl) and its related compounds. VI. Structure-analgesic activity relationship for fentanyl, methyl-substituted fentanyls and other analogues. Forensic Toxicol 26: 1-5.10.1007/s11419-007-0039-1]Search in Google Scholar
[Hunskar S, Hole K. (1987). The formalin test in mice: dissociation between infl ammatory and non-infl ammatory pain. Pain 30: 103-114.]Search in Google Scholar
[Irwin S. (1964). Drug screening and evaluation of new compounds in animals. in Animal and clinical techniques in drug evaluation (Nodin JH, Siegler PE eds) pp 36-54, Year Book Medical Publishers, Chicago.]Search in Google Scholar
[Irwin S. (1968). Comprehensive observational assessment: Ia. A systematic, quantitative procedure for assessing the behavioural and physiologic state of the mouse. Psychopharmacologia (Berl) 13: 222-257.]Search in Google Scholar
[Jagerovic N, Cano C, Elguero J, Goya P, Callado LF, Meana JJ, Giron R, Abalo R, Ruiz D, Goicoechea C, Martin MA. (2002). Long-Acting Fentanyl Analogues: Synthesis and Pharmacology of N-(1-Phenylpyrazolyl)-N-(1-phenylalkyl-4- piperidyl)propanamides. Bioorg Med Chem 10: 817-827.]Search in Google Scholar
[Janssen PAJ, Niemegeers CJE, Dony JGH. (1963). The inhibitory eff ect of fentanyl and other morphine-like analgesics on the warm water induced tail withdrawal refl ex in rats. Arzneimittel-Forsch-Drug Res 13: 502-507.]Search in Google Scholar
[Jumbelic MI. (2010). Deaths with transdermal fentanyl patches. Am J Forensic Med Pathol 31: 18-21.]Search in Google Scholar
[Kalso E, Edwards JE, Moore RA, McQuay HJ. (2004). Opioids in chronic noncancer pain: systematic review of effi cacy and safety. Pain 112: 372-380.]Search in Google Scholar
[Kieff er BL, Evans CJ. (2009). Opioid receptors: from binding sites to visible molecules in Vivo. Neuropharmacology 56: 205-212.]Search in Google Scholar
[Kieff er BL. (1995). Recent advances in molecular recognition and signal transduction of active peptides: receptors for opioid peptides. Cell Mol Neurobiol 15: 615-635.]Search in Google Scholar
[Lambert DG. (2004). Drugs and receptors. Contin Educ Anaesth Crit Care Pain 4: 181-184.]Search in Google Scholar
[Leavitt SB. (2009). Opioid antagonists, naloxone & naltrexene-Aids for pain management. An overview of clinical evidence. Pain Treatment Topics, Glenview, IL 60025 http: //Pain-Topics.Org, 1-16.]Search in Google Scholar
[Lee YS, Nyberg J, Moye S, Agnes RS, Davis P, Ma SW, Lai J, Porreca F, Vardanyan R, Hruby VJ. (2007). Understanding the structural requirements of 4-anilidopiperidine analogues for biological activities at mu and delta opioid receptors. Bioorg Med Chem Lett 17: 2161-2165.]Search in Google Scholar
[Lemmens H. (1995). Pharmacokinetic-pharmacodynamic relationships for opioids in balanced anaesthesia. Clin Pharmacokinet 29: 231-242.]Search in Google Scholar
[Litchfi eld JTJr, Wilcoxon F. (1949). A simplifi ed method of evaluating dose-effect experiments. J Pharm Exp Ther 96: 99-113.]Search in Google Scholar
[Mather LE. (1983). Clinical pharmacokinetics of fentanyl and its newer derivatives. Clin Pharmacokinet 8: 422-446.]Search in Google Scholar
[Matosiuk D, Fidecka S, Antkiewicz-Michaluk L, Lipkowski J, Dybala I, Koziol AE. (2002). Synthesis and pharmacological activity of new carbonyl derivatives of 1-aryl-2-iminoimidazolidine. Part 2. Synthesis and pharmacological activity of 1,6-diaryl-5,7(1H)dioxo-2,3-dihydroimidazo[1,2-a][1,3,5]triazines. Eur J Med Chem 37: 761-772.]Search in Google Scholar
[Mayes S, Ferrone M. (2006). Fentanyl HCl patient-controlled iontophoretic transdermal system for the management of acute postoperative pain: Summary/formulary recommendation. Ann Pharmacother 40: 2178-2186.]Search in Google Scholar
[McGinty J, Friedman D. (1988). Opioids in the hippocampus. Natl Inst Drug Abuse Res Monogr Ser 82: 1-145.]Search in Google Scholar
[Meunier CJ, Burton J, Cumps J , Verbeeck RK. (1998). Evaluation of the formalin test to assess the analgesic activity of difl unisal in the rat. Eur J Pharm Sci 6: 307-312.]Search in Google Scholar
[Mićović IV, Ivanović MD, Vuckovic SM, Prostran MŠ, Došen-Mićović L, Kiricojević VD. (2000). The synthesis and preliminary pharmacological evaluation of 4-methyl fentanyl. Bioorg Med Chem Lett 10: 2011-2014.]Search in Google Scholar
[Pasternak GW. (2004). Multiple opiate receptors: deja vu all over again. Neuropharmacology 47: 312-323.]Search in Google Scholar
[Portoghese PS. (1992). The role of concepts in structure-activity-relationship studies of opioid ligands. J Med Chem 35: 1927-1937.]Search in Google Scholar
[Scholz J, Steinfath M, Schulz M. (1996). Clinical pharmacokinetics of alfentanyl, fentanyl and sufentanyl. An update. Clin Pharmacokinet 31: 275-292.]Search in Google Scholar
[Smith MT. (2008). Diff erences between and combinations of opioids re-visited. Curr Opin Anaesthesiol 21: 596-601.]Search in Google Scholar
[Spetea M, Bohotin CR, Asim MF, Stubegger K, Schmidhammer H. (2010). In vitro and in vivo pharmacological profi le of the 5-benzyl analogue of 14-methoxymetopon, a novel mu opioid analgesic with reduced propensity to alter motor function. Eur J Pharm Sci 4: 125-135.]Search in Google Scholar
[Vogel HG. (2002). Psychotropic and neurotropic activity. In Drug Discovery and Evaluation. Pharmacological Assays. Springer, Berlin.]Search in Google Scholar
[Van Nimmen NFJ, Poels KLC, Veulemans HAF. (2004). Highly sensitive gas chromatographic- mass spectrometric screening method for the determination of picogram levels of fentanyl, sufentanil and alfentanil and their major metabolites in urine of opioid exposed workers. J Chromatogr B 804: 375-387.]Search in Google Scholar
[Vučkovic S, Prostran M, Ivanović M, Dosen-Mićović L, Vujović KS, Vucetic C, Kadija M, Mikovic Z. (2011). Pharmacological evaluation of 3-carbomethoxy fentanyl in mice. Pharmaceuticals 4: 233-243.]Search in Google Scholar
[Vučkovic S, Prostran M, Ivanović M, Ristović Z, Stojanović R. (2000). Antinociceptive activity of the novel fentanyl analogue iso-carfentanil in rats. Jpn J Pharmacol 84: 188-195.]Search in Google Scholar
[Vučkovic S, Savić VK, Ivanović M, Došen-Mićović L, Todorovic Z, Vučetić Č., Prostran M., Prostran Milica. (2012). Neurotoxicity evaluation of fentanyl analogs in rats. Acta Veterinaria 62: 3-15.]Search in Google Scholar
[Yassen A, Olofsen E, Kan J, Dahan A, Danhof M. (2008). Pharmacokineticpharmacodynamic modeling of the eff ectiveness and safety of buprenorphine and fentanyl in rats. Pharmaceut Res 25: 183-193. ]Search in Google Scholar