5-HT

Duloxetine ((S)-Duloxetine hydrochloride) (sold under the brand names Cymbalta, Ariclaim, Xeristar, Yentreve, Duzela, Dulane) is an SNRI (serotonin-norepinephrine reuptake inhibitor) that Eli Lilly makes and sells. It is recommended for both generalized anxiety disorder (GAD) and major depressive disorder. Moreover, duloxetine is approved for the treatment of musculoskeletal pain and osteoarthritis. Due to worries about liver toxicity and suicidal thoughts, duloxetine was not approved for this indication in the US; however, it was approved in Europe, where it is advised as a supplement to surgery in cases of stress urinary incontinence. It can also relieve the symptoms of painful peripheral neuropathy, particularly diabetic neuropathy, and it is used to control the symptoms of fibromyalgia. Duloxetine is mostly used to treat major depressive disorder, general anxiety disorder, stress-related urinary incontinence, painful peripheral neuropathy, fibromyalgia, chronic lower back pain, and musculoskeletal pain linked to osteoarthritis. Numerous other indications are being researched on it[1][2].

Oxaliplatin is a widely used chemotherapy agent, but induces serious peripheral neuropathy. Duloxetine is a dual reuptake inhibitor of serotonin and norepinephrine, and is shown to be effective against pain. However, whether and how duloxetine can attenuate oxaliplatin-induced allodynia in rodents is not clearly understood. A single injection of oxaliplatin (6 mg/kg, intraperitoneal; i.p.) induced a cold and mechanical allodynia, which was assessed by acetone and von Frey filament tests, respectively. When significant allodynic signs were observed, three different doses of duloxetine (10, 30, and 60 mg/kg, i.p.) were injected. Administration of 30 and 60 mg/kg of duloxetine significantly reduced the allodynia, whereas 10 mg/kg did not. By using an in vivo extracellular recording method, we further confirmed that 30 mg/kg of duloxetine could significantly inhibit the hyperexcitability of spinal wide dynamic range (WDR) cells. The anti-allodynic effect of duloxetine was completely blocked by an intrathecal injection of phentolamine (non-selective α-adrenergic receptor antagonist, 20 μg), or prazosin (α₁-adrenergic receptor antagonists, 10 μg); however, idazoxan (α₂-adrenergic receptor antagonist, 10 μg) did not block it. In conclusion, we suggest that duloxetine may have an effective protective action against oxaliplatin-induced neuropathic pain and spinal hyperexcitability, which is mediated by spinal α₁-adrenergic receptors[2].

Lactate Dehydrogenase Assay[1]
Lactate dehydrogenase (LDH) is an intracellular enzyme that is released to the supernatant during cell death. The LDH release into the incubation medium after cell membrane damage was measured using an LDH diagnostic kit according to manufacturer’s instructions. There were three repeats of each group for statistical analysis.[1]

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Lipid Peroxidation Assay[1]
The lipid peroxidation level was determined by measuring the concentration of malondialdehyde (MDA), which is the end product of lipid peroxidation and reacts with TBA to form a fluorescence adduct. The total MDA quantities were determined using a Lipid Peroxidation MDA Assay Kit according to manufacturer’s instructions. The total protein content was determined using the Pierce BCA Protein Assay Kit. The MDA level for each group was the total MDA divided by the total protein. There were three repeats of each group for statistical analysis.

Cell Viability Assay[1]
Cells were seeded in 96-well plates at a density of 2 × 105 cells per well, grown for 24 h, and then treated with the drugs according to time-dependence or dose-dependence protocols. Each treatment was conducted in triplicate. After the drug treatments, the cell viability was assayed using a Cell Counting Kit-8 (CCK-8) according to the manufacturer’s instructions. CCK-8 uses the sensitive colorimetric WST-8 assay to determine the number of viable cells. WST-8 is a highly water-soluble tetrazolium salt, with the chemical designation of 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt.[1]

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Colony-Forming Assay[1]
N2a cells were treated with the various indicated concentrations of duloxetine for 24 h. Triplicate wells of 6-well plates containing 1 × 103 cells were treated with various concentrations of duloxetine and maintained for another 21 days. The colonies were fixed with methanol, stained with a 0.1% crystal violet solution in 1 h at room temperature, and counted. The colony formation assay was repeated three times.[1]

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N2a Cell Differentiation[1]
N2a cells were differentiated by a protocol that involved RA addition and serum withdrawal. The differentiation medium was DMEM supplemented with 20 μM RA, 100 U/ml penicillin and 100 μg/ml streptomycin. Neurites were identified as cell processes greater than two cell body diameters in length. Differentiated cells were defined as those bearing neurites. The percentage was statistically analyzed by counting 180 cells in six randomly chosen fields per well. The neurite length was defined as the distance from the cell body to the tips of the neurites. The length of the longest neurite was measured in at least 50 cells in five randomly chosen fields using the ImageJ software. To evaluate the cell toxicity, N2a cells that were committed to differentiation with RA were treated with the addition of 12.5 μM duloxetine or 12.5 μM duloxetine plus 10 μM rifampicin for 24 h. Statistical comparisons of the cell morphology were conducted between control, RA, RA + duloxetine and RA + duloxetine + rifampicin groups after a 24-h treatment (n = 3). The cell viability and cell morphology were recorded each day during the full differentiation period (n = 3). Furthermore, the events associated with cell cycle and cell death were analyzed at various time points in the control and RA groups to permit interpretation of the key changes during the N2a cell differentiation. Statistical analyses of cell death (n = 4), cell cycle (n = 4) and biochemical changes (n = 3) were conducted in the control, RA, RA + duloxetine groups after the 24-h treatment.

Duloxetine and α-Adrenergic Receptor Antagonists Administration[2]
Duloxetine was dissolved in distilled water (D.W.). Different doses of duloxetine (10, 30, and 60 mg/kg) were administered (i.p.). To test which adrenergic receptor subtypes mediated the anti-allodynic effects of duloxetine in oxaliplatin-administered mice, antagonists were administered intrathecally 20 min prior to duloxetine treatments. Non-selective α-adrenergic antagonists (phentolamine, 20 μg), α1-adrenergic receptor antagonists (prazosin, 10 μg), and α2-adrenergic receptor antagonists (idazoxan, 10 μg) were administered in volumes of 5 μL. The dose of each antagonist was determined based on previously conducted studies showing the selective and effective antagonistic action against adrenergic receptor-mediated responses.[2]

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In Vivo Extracellular Recording[2]
Extracellular recordings were made from Sprague-Dawley rats, three to five days after the administration of oxaliplatin, when rats exhibited significant mechanical and cold allodynia. Extracellular recordings were carried out as previously described. In brief, rats were anesthetized with urethane (1.5 g/kg, i.p.). The spinal cords of the animals, which were fixed in a stereotaxic frame, was exposed from T13–L2 and irrigated with oxygenated (95% O2-5% CO2 gas) Krebs solution (in mM: 117 NaCl, 3.6 KCl, 2.5 CaCl2, 1.2 MgCl2, 1.2 NaH2PO4, 11 glucose, and 25 NaHCO3) at a flow rate of 10–15 mL/min at 38 ± 1 °C. Based on their responses to brush, pressure, pinch, and acetone stimulations, the WDR cells were classified. Extracellular single-unit recordings were made with a low-impedance insulated tungsten microelectrode (impedance of 10 MΩ). For mechanical stimuli, brush, press, and pinch stimulations were applied to the lateral and ventral surfaces of the hind paw. Brush stimulus was given by brushing the receptive field five times with a camel brush. Press stimulus was given by pressing the receptive field for 4 s using the blunt tip of the camel brush with a diameter of 0.5 cm and a magnitude of about 20 g. Pinch stimulation was given by pinching the skin using toothed forceps for 3 s. For cold stimulation, 10 μL of acetone drop was applied to the receptive fields.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Little published information is available on the use of duloxetine during breastfeeding; however, the dose in milk is low and serum levels were low in two breastfed infants. If the mother requires duloxetine, it is not a reason to discontinue breastfeeding. Expert opinion finds duloxetine acceptable to use during breastfeeding, and a safety scoring system finds duloxetine use to be possible to use cautiously during breastfeeding. An alternate drug that has been better studied may be preferred, especially while nursing a newborn or preterm infant. Monitor the infant for drowsiness and adequate feeding, weight gain and developmental milestones, especially in younger, exclusively breastfed infants and when using combinations of psychotropic drugs. Galactorrhea has been reported in women taking duloxetine.
◉ Effects in Breastfed Infants
A partially nursing mother was taking duloxetine 90 mg and extended-release methylphenidate (Concerta) 36 mg daily for ADHD, generalized anxiety disorder, borderline personality disorder, and depression. She partially (amount not stated) breastfed her infant for about 1 month. At 6 months of age, infant's development was considered to be normal, except for recurrent pneumonia caused by congenital pulmonary airway malformation. Another mother took duloxetine 60 mg daily while partially (amount not stated) nursing her infant. At 6 weeks of age, no adverse events were observed in the exposed infant.
One mother reported a possible adverse reaction of drowsiness in her baby in the first few weeks after birth. She was taking agomelatine in an unspecified dose with duloxetine 90 mg daily. She attributed the drowsiness to agomelatine and continued breastfeeding her baby until 9 months of age. She reported some developmental concerns of speech and low muscle tone in her baby who was 9 months of age at the time of follow-up.
◉ Effects on Lactation and Breastmilk
In a small prospective study, 8 primiparous women who were taking a serotonin reuptake inhibitor (SRI; 3 taking fluoxetine and 1 each taking citalopram, duloxetine, escitalopram, paroxetine or sertraline) were compared to 423 mothers who were not taking an SRI. Mothers taking an SRI had an onset of milk secretory activation (lactogenesis II) that was delayed by an average of 16.7 hours compared to controls (85.8 hours postpartum in the SRI-treated mothers and 69.1 h in the untreated mothers), which doubled the risk of delayed feeding behavior compared to the untreated group. However, the delay in lactogenesis II may not be clinically important, since there was no statistically significant difference between the groups in the percentage of mothers experiencing feeding difficulties after day 4 postpartum.
After one nonpregnant woman began taking duloxetine, her serum prolactin increased and previous galactorrhea, which had decreased after stopping venlafaxine, increased again. After stopping duloxetine, her prolactin decreased to normal and galactorrhea ceased.
A woman who was taking duloxetine at an unspecified dose for depression reported a milky discharge from her nipples. She had not experienced this effect with previous antidepressant therapy. Her serum prolactin was elevated, and an MRI of her head found no tumors. Duloxetine was stopped and she was treated with escitalopram 20 mg daily and cabergoline 0.5 mg twice weekly for one month. At this time her serum prolactin was normal and the galactorrhea had stopped.
In a study of cases of hyperprolactinemia and its symptoms (e.g., gynecomastia) reported to a French pharmacovigilance center, duloxetine was not found to have an increased risk of causing hyperprolactinemia compared to other drugs.
A woman taking duloxetine 60 mg daily for depression complained of a milky breast discharge, breast fullness, and breast pain, after taking the drug for a total of 10 weeks. Duloxetine was discontinued and bupropion was started. Two weeks after stopping duloxetine, galactorrhea improved. Six weeks after stopping duloxetine, her serum prolactin had dropped from the previous level of 37.9 mcg/L to 20.2 mcg/L. Her galactorrhea was probably caused by duloxetine.
A woman being treated for migraine with duloxetine 30 mg daily began to have bilateral galactorrhea during the tenth week of treatment. At that time and on repeated measurements, her serum prolactin level was within the normal range. Her galactorrhea ceased 3 days after discontinuation of duloxetine. The authors found that her galactorrhea was probably caused by duloxetine.
An observational study looked at outcomes of 2859 women who took an antidepressant during the 2 years prior to pregnancy. Compared to women who did not take an antidepressant during pregnancy, mothers who took an antidepressant during all 3 trimesters of pregnancy were 37% less likely to be breastfeeding upon hospital discharge. Mothers who took an antidepressant only during the third trimester were 75% less likely to be breastfeeding at discharge. Those who took an antidepressant only during the first and second trimesters did not have a reduced likelihood of breastfeeding at discharge. The antidepressants used by the mothers were not specified.
A retrospective cohort study of hospital electronic medical records from 2001 to 2008 compared women who had been dispensed an antidepressant during late gestation (n = 575) to those who had a psychiatric illness but did not receive an antidepressant (n = 1552) and mothers who did not have a psychiatric diagnosis (n = 30,535). Women who received an antidepressant were 37% less likely to be breastfeeding at discharge than women without a psychiatric diagnosis, but no less likely to be breastfeeding than untreated mothers with a psychiatric diagnosis. None of the mothers were taking duloxetine.
A woman with major depressive disorder received duloxetine 40 mg twice daily. After 2 weeks, she developed menstrual irregularities and a milky discharge from her breasts. Her serum prolactin was elevated at 205 mcg/L. The duloxetine dosage was decreased to 60 mg once daily and aripiprazole was begun at 2.5 mg daily and then increased to 5 mg daily. Within 2 weeks, galactorrhea had stopped and the serum prolactin had decreased to 118 mcg/L. Six weeks later, serum prolactin was 39 mcg/L. The combination was continued for another 39 weeks with no return of galactorrhea.
A 16-year-old girl was admitted for depression and suicide attempts. She had previously experienced galactorrhea while taking risperidone and escitalopram. She was started on duloxetine 20 mg daily which was increased to 40 mg daily after 5 days. Two days later, small amounts of milk appeared from the right breast. Her serum prolactin was mildly elevated at 26 mcg/L. The dose was reduced to 20 mg daily and the milk production ceased.
A woman with depression was treated with duloxetine 30 mg daily for 1 month, then 60 mg daily. After 4 months of therapy she presented with amenorrhea, lactation and hyperprolactinemia. The patient was treated with cabergoline 0.5 mg twice weekly and duloxetine was discontinued. One month later, the serum prolactin level was normal.
A woman with multiple sclerosis had been treated with duloxetine 60 mg daily for pain and depression for 3 months. She noted a milk-like breast discharge for a month and her serum prolactin was elevated. Duloxetine was changed to escitalopram 10 mg daily. Within days, her galactorrhea stopped and her serum prolactin decreased. Cabergoline 0.25 mg twice weekly was instituted after other causes of hyperprolactinemia were ruled out. The dose was reduced after 3 months and her serum prolactin remained normal.
In a study of 80,882 Norwegian mother-infant pairs from 1999 to 2008, new postpartum antidepressant use was reported by 392 women and 201 reported that they continued antidepressants from pregnancy. Compared with the unexposed comparison group, late pregnancy antidepressant use was associated with a 7% reduced likelihood of breastfeeding initiation, but with no effect on breastfeeding duration or exclusivity. Compared with the unexposed comparison group, new or restarted antidepressant use was associated with a 63% reduced likelihood of predominant, and a 51% reduced likelihood of any breastfeeding at 6 months, as well as a 2.6-fold increased risk of abrupt breastfeeding discontinuation. Specific antidepressants were not mentioned.

[1]. Dose-dependent noradrenergic and serotonergic properties of venlafaxine in animal models indicative of antidepressant activity. Psychopharmacology (Berl). 1998 Jul;138(1):1-8.

[2]. Desvenlafaxine succinate: A new serotonin and norepinephrine reuptake inhibitor. J Pharmacol Exp Ther. 2006 Aug;318(2):657-65. Epub 2006 May 4.

(S)-duloxetine hydrochloride is a duloxetine hydrochloride in which the duloxetine moiety has S configuration. It has a role as an antidepressant. It contains a (S)-duloxetine.
Duloxetine Hydrochloride is the hydrochloride salt of duloxetine, an orally bioavailable fluoxetine derivative belonging to the class of selective serotonin (5-HT) and norepinephrine (NE) reuptake inhibitors (SNRIs), with central pain inhibitory, anxiolytic and antidepressant activities. Upon oral administration, duloxetine selectively prevents the reuptake of 5-HT and NE via transporter complexes on the pre-synaptic membrane, thereby increasing the level of these neurotransmitters within the synaptic cleft. This potentiates serotonergic and noradrenergic activities in the central nervous system (CNS), and alleviates anxiety, depression, and neuropathy sensations, such as neuropathic pain.
A thiophene derivative and selective NEUROTRANSMITTER UPTAKE INHIBITOR for SEROTONIN and NORADRENALINE (SNRI). It is an ANTIDEPRESSIVE AGENT and ANXIOLYTIC, and is also used for the treatment of pain in patients with DIABETES MELLITUS and FIBROMYALGIA.
See also: Duloxetine (has active moiety).

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Drug Indication
Treatment of major depressive disorder; Treatment of diabetic peripheral neuropathic pain; Treatment of generalised anxiety disorder; Duloxetine Mylan is indicated in adults.
Treatment of major depressive disorder. Treatment of diabetic peripheral neuropathic pain. Treatment of generalised anxiety disorder. Cymbalta is indicated in adults.
Yentreve is indicated for women for the treatment of moderate to severe stress urinary incontinence (SUI).
Duloxetine Lilly is indicated in adults for: Treatment of major depressive disorderTreatment of diabetic peripheral neuropathic painTreatment of generalised anxiety disorderDuloxetine Lilly is indicated in adults.
Treatment of diabetic peripheral neuropathic pain. Ariclaim is indicated in adults.
Treatment of diabetic peripheral neuropathic pain in adults.
Treatment of chronic pain, Treatment of diabetic neuropathic pain, Treatment of generalised anxiety disorder, Treatment of major depressive disorder, Treatment of stress urinary incontinence

C18H20CLNOS

333.88

333.095

C, 64.75; H, 6.04; Cl, 10.62; N, 4.20; O, 4.79; S, 9.60

136434-34-9

Duloxetine; 116539-59-4; Duloxetine-d3 hydrochloride; 1435727-97-1; (±)-Duloxetine hydrochloride; 947316-47-4; Duloxetine metabolite Para-Naphthol Duloxetine; 949095-98-1

60834

White to off-white solid powder

466.2ºC at 760 mmHg

118-122ºC

235.7ºC

5.823

2

3

6

22

312

1

Cl[H].S1C([H])=C([H])C([H])=C1[C@]([H])(C([H])([H])C([H])([H])N([H])C([H])([H])[H])OC1=C([H])C([H])=C([H])C2=C([H])C([H])=C([H])C([H])=C12

BFFSMCNJSOPUAY-LMOVPXPDSA-N

InChI=1S/C18H19NOS.ClH/c1-19-12-11-17(18-10-5-13-21-18)20-16-9-4-7-14-6-2-3-8-15(14)16;/h2-10,13,17,19H,11-12H2,1H3;1H/t17-;/m0./s1

(3S)-N-methyl-3-naphthalen-1-yloxy-3-thiophen-2-ylpropan-1-amine;hydrochloride

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (7.49 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (7.49 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (7.49 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 2% DMSO +30% PEG 300 +ddH2O: 30mg/mL

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Solubility in Formulation 5: 140 mg/mL (419.31 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)