Absorption, Distribution and Excretion
Racemic milnacipram demonstrates an absolute bioavailability of about 85-90% following oral administration. Maximum concentrations of the racemic agent are reached within 2-4 hours after oral dosing, and steady-state levels are obtained by 36-48 hours. Conversely, the relative bioavailability of levomilnacipram has been documented as 92%. The median time to peak concentration Tmax for levomilnacipram is about 6-8 hours after oral administration. After daily dosing of levomilnacipram 120 mg, the mean Cmax value is 341 ng/mL, and the mean steady-state AUC value is 5196 ng.h/mL. In general, the administration of either racemic milnacipram or levomilnacipram with food does not affect the medication's oral bioavailability.
Levomilnacipran and its metabolites are eliminated primarily by renal excretion. Following oral administration of 14C-levomilnacipran solution, approximately 58% of the dose is excreted in urine as unchanged levomilnacipran. N-desethyl levomilnacipran is the major metabolite excreted in the urine and accounted for approximately 18% of the dose. Other identifiable metabolites excreted in the urine are levomilnacipran glucuronide (4%), desethyl levomilnacipran glucuronide (3%), p-hydroxy levomilnacipran glucuronide (1%), and p-hydroxy levomilnacipran (1%).
The mean volume of distribution recorded for racemic milnacipran following a single intravenous dose to healthy subjects was approximately 400 L. Alternatively, levomilnacipran is widely distributed with an apparent volume of distribution of 387-473 L.
The total plasma clearance determined for milnacipran is approximately 40 L/h.

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Metabolism / Metabolites
It has been determined that levomilnacipran undergoes desethylation and hydroxylation to generate desethyl levomilnacipran and p-hydroxy-levomilnacipran, respectively. Both oxidative metabolites undergo further conjugation with glucuronide to form the conjugate milnacipran carbamoyl-O-glucuronide. The desethylation is catalyzed primarily by CYP3A4 with minor contribution by CYP2C8, 2C19, 2D6, and 2J2. Additionally, it is the general understanding that there is no interconversion between the enantiomers of milnacipran in the body.

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Biological Half-Life
The terminal elimination half-life documented for racemic milnacipran is approximately 6-8 hours, where d-milnacipran has a longer elimination half-life of 8-10 hours compared to that of the l-enantionmer at 4-6 hours. Alternatively, the terminal elimination half-life determined specifically for levomilnacipran formulations is about 12 hours.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Amounts of milnacipran in breastmilk are low and would not be expected to cause any adverse effects in breastfed infants. However, until more data become available, milnacipran should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Galactorrhea is reported by the manufacturer to be a side effect of milnacipran. One woman who was being treated for depression took an intentional overdose of 950 mg of milnacipran orally. From day 5 to day 15 after the overdose, the patient noted a flow of milk from her left breast. The galactorrhea resolved without treatment.
In a study of cases of hyperprolactinemia and its symptoms (e.g., gynecomastia) reported to a French pharmacovigilance center, milnacipran was not found to have an increased risk of causing hyperprolactinemia compared to other drugs.
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 milnacipran.
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.

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Protein Binding
The protein binding determined for racemic milnacipran is 13%. Conversely, the plasma protein binding documented for levomilnacipran is 22% over a concentration range of 10 to 1000 ng/mL.

[1]. Biochemical profile of midalcipran (F 2207), 1-phenyl-1-diethyl-aminocarbonyl-2-aminomethyl-cyclopropane (Z) hydrochloride, a potential fourth generation antidepressant drug. Neuropharmacology. 1985 Dec;24(12):1211-9.

[2]. Preclinical pharmacology of milnacipran. Int Clin Psychopharmacol. 1996 Sep;11 Suppl 4:9-14.

Pharmacodynamics
When utilized to treat fibromyalgia, the effect of milnacipran on the QTcF interval in patients was measured in a double-blind placebo-and positive-controlled parallel study in 88 healthy subjects using three to six times the recommended therapeutic dose for fibromyalgia at 600 mg/day. After baseline and placebo adjustment, the maximum mean QTcF change was 8 ms - an increase that is generally not considered to be clinically significant. Conversely, when used for treating major depressive disorder (MDD), non-clinical studies have shown that levomilnacipran binds with high affinity to the norepinephrine (NE) and serotonin (5-HT) transporters (Ki = 71-91 nM and 11 nM respectively at human transporters). Levomilnacipran inhibits the uptake of both NE and 5-HT in vitro and in vivo; preferentially inhibiting reuptake of NE over 5-HT by approximately 2-fold. Levomilnacipran does not directly affect the uptake of dopamine or other neurotransmitters. Levomilnacipran has no significant affinity for serotonergic (5-HT1-7), α- and β-adrenergic, muscarinic (M1-5), histamine (H1-4), dopamine (D1-5), opiate, benzodiazepine, and γ-aminobutyric acid (GABA) receptors in vitro. Levomilnacipran has no significant affinity for Ca++, K+, Na+, and Cl– channels and does not inhibit the activity of human monoamine oxidases (MAO-A and MAO-B) or acetylcholinesterase. Moreover, in ECG studies with levomilnacipran used to treat MDD, although no clinically significant changes in QTcF interval (QTcF=QT/RR0.33) were noted, it appears that the agent can cause increases in heart rate and blood pressure. In particular, it appears that the maximum therapeutic dose of levomilnacipran at 120 mg/day is capable of causing a maximum mean difference in heart rate from placebo of 20.2 bpm and a mean difference in systolic and diastolic blood pressure from placebo ranging from 3.8 to 7.2 mmHg and 6.1 to 8.1 mmHg, respectively. Alternatively, a supratherapeutic dose of 300 mg/day is capable of causing a maximum mean difference in heart rate from placebo of 22.1 bpm and a mean difference in systolic and diastolic blood pressure from placebo ranging from 5.4 to 7.9 mmHg and 7.9 to 10.6 mmHg, respectively.

C15H22N2O

246.34798

246.173

92623-85-3

Milnacipran hydrochloride;101152-94-7;Milnacipran ((1S-cis) hydrochloride);175131-60-9;Dextromilnacipran;96847-55-1;Milnacipran-d10 hydrochloride;1217774-40-7

65833

Typically exists as solid at room temperature

1.1±0.1 g/cm3

393.0±21.0 °C at 760 mmHg

228-228.5ºC

191.5±22.1 °C

0.0±0.9 mmHg at 25°C

1.554

1.23

1

2

5

18

295

2

C([C@@]1(C[C@@H]1CN)C1C=CC=CC=1)(=O)N(CC)CC

GJJFMKBJSRMPLA-HIFRSBDPSA-N

InChI=1S/C15H22N2O/c1-3-17(4-2)14(18)15(10-13(15)11-16)12-8-6-5-7-9-12/h5-9,13H,3-4,10-11,16H2,1-2H3/t13-,15+/m1/s1

(1R,2S)-2-(aminomethyl)-N,N-diethyl-1-phenylcyclopropane-1-carboxamide

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

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

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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