Absorption, Distribution and Excretion
Neostigmine bromide is poorly absorbed in the gastrointestinal tract after oral administration. Neostigmine…is poorly absorbed orally, thus requiring much larger doses than the parenteral route. …The effective parenteral dose of neostigmine in humans is 0.5 to 2.0 mg, with an equivalent oral dose of 30 mg or more. High oral doses may lead to toxicity if intestinal absorption is enhanced for any reason. …Neostigmine excretion is slowed in patients with severe renal disease, therefore this anticholinesterase drug is an acceptable option for patients with renal failure. We determined the pharmacokinetics of neostigmine in patients with normal renal function and compared them with those in patients who underwent kidney transplantation or bilateral nephrectomy. 10 to 15 minutes before the end of surgery and anesthesia, the d-tubocurarine infusion was stopped, and neostigmine 0.07 mg/kg and atropine 0.03 mg/kg were administered intravenously over 2 minutes. In patients without kidneys, the elimination half-life was prolonged. Total serum clearance decreased from 16.7 ml/kg/min in patients with normal renal function to 7.8 ml/kg/min in patients without renal function. The pharmacokinetics of neostigmine were not different after kidney transplantation compared to patients with normal renal function. Renal excretion accounts for 50% of neostigmine clearance. Metabolism/Metabolites Neostigmine is hydrolyzed by cholinesterases and can also be metabolized in the liver by microsomal enzymes. Neostigmine is destroyed by plasma esterases, and quaternary ammonium alcohol and the parent compound are excreted in the urine. Neostigmine is converted to 3-hydroxyphenyltrimethylammonium in rats. ROBERTS, JB et al.; Biochemical Pharmacology 17: 9 (1968). /Excerpt from Table/ Biological Half-Life The half-life is 42 to 60 minutes, with a mean half-life of 52 minutes. Pharmacokinetics of neostigmine were evaluated in humans after intravenous and oral administration. Following intravenous administration, the mean plasma half-life of neostigmine is 0.89 hours. After oral administration, peak plasma concentrations occur 1–2 hours post-administration, but bioavailability is only 1–2% of the administered dose. In patients with myasthenia gravis, the attenuation of repetitive nerve stimulation-induced muscle electrical responses correlated well with neostigmine plasma concentrations.

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
Limited data suggest that neostigmine may be acceptable for treating myasthenia gravis during lactation, but pyridostigmine may be preferred. Newborns should be closely monitored, as abdominal cramps have been reported after each feeding. Due to the short half-life of neostigmine, a single dose reversing postoperative neuromuscular blockade is unlikely to have any adverse effects on breastfed infants other than transient ones.
◉ Effects on Breastfed Infants
Six infants born to mothers receiving neostigmine for myasthenia gravis have been reported to be successfully breastfed. One newborn appeared to experience abdominal cramps after each feeding, possibly caused by neostigmine, although the drug was not detected in the mother's breast milk.
◉ Effects on Lactation and Breast Milk
As of the revision date, no published information has been found regarding neostigmine use in lactating women. In animal studies, cholinergic drugs can increase oxytocin release and have varying effects on serum prolactin levels. For established lactating mothers, prolactin levels may not affect their ability to breastfeed. Protein Binding: Anticholinesterase drugs bind to human serum albumin at a rate between 15% and 25%. Interactions: The effects of anticholinesterase drugs on autonomic effector cells and the cortical and subcortical regions of the central nervous system (where receptors are primarily muscarinic) can be blocked by atropine. Anticholinesterase Drugs: The various effects of anticholinesterase drugs on skeletal muscle can be enhanced by adrenaline or ephedrine… and blocked by D-tubocurarine. Quinidine: Quinidine may antagonize the effects of neostigmine (prostigmine) in the treatment of myasthenia gravis. …The anticholinergic effects of quinidine may antagonize the vagal nerve excitatory effects of cholinergic drugs. Quinidine should be used with caution in patients with myasthenia gravis receiving cholinergic therapy. Neostigmine failed to alter the occurrence of neuromuscular blockade at high local concentrations of tubocurarine. For more complete data on drug interactions of neostigmine (13 in total), please visit the HSDB record page.

Neostigmine is a quaternary ammonium ion compound with an aniline ion as its core structure. Three methyl substituents are attached to the aniline nitrogen atom, and a 3-[(dimethylcarbamoyl)oxy] substituent is attached at the 3-position. It is a parasympathomimetic drug and acts as a reversible acetylcholinesterase inhibitor. It can act as an EC 3.1.1.7 (acetylcholinesterase) inhibitor and as an antidote for curare poisoning. It is a cholinesterase inhibitor used to treat myasthenia gravis and to reverse the effects of muscle relaxants such as galamine and tubocurarine. Unlike physostigmine, neostigmine cannot cross the blood-brain barrier. Neostigmine is a cholinesterase inhibitor. The mechanism of action of neostigmine is as a cholinesterase inhibitor. Neostigmine is a parasympathomimetic drug and acts as a reversible acetylcholinesterase inhibitor. It is a cholinesterase inhibitor used to treat myasthenia gravis and to reverse the effects of muscle relaxants such as galamine and tubocurarine. Unlike physostigmine, neostigmine cannot cross the blood-brain barrier. See also: Neostigmine methyl sulfate (in salt form). Drug Indications Neostigmine treats the symptoms of myasthenia gravis by improving muscle tone. Mechanism of Action Neostigmine is a parasympathomimetic drug, specifically a reversible cholinesterase inhibitor. This drug inhibits acetylcholinesterase, which is responsible for the degradation of acetylcholine. Therefore, when acetylcholinesterase is inhibited, the level of acetylcholine increases. Neostigmine indirectly stimulates nicotinic and muscarinic receptors involved in muscle contraction by interfering with the breakdown of acetylcholine. It cannot cross the blood-brain barrier. …The pharmacological action of anticholinesterase drugs is primarily attributed to their ability to prevent the hydrolysis of acetylcholine by acetylcholinesterase at cholinergic transmission sites. Therefore, neurotransmitters accumulate, and the activity of acetylcholinesterase (ACH), released by cholinergic impulses or leaked from nerve endings, is enhanced. Neostigmine increased the amplitude of micro-endplate potentials and endplate potentials in isolated frog sciatic nerve-sartorius muscle complexes, but did not affect quantum content. This suggests that cholinesterase inhibition is the sole mechanism of action. Long-term (24–96 hours) treatment of mouse-derived myoblast cell lines (G8) with neostigmine significantly reduced the binding of α-bu-x venom (α-BuTx) to these cells. Protein synthesis in these cultures was significantly reduced, and cell morphology degenerated. Myotubes maintained a mildly hyperpolarized resting membrane potential and were able to produce overshoot action potential responses to iontophoretic acetylcholine (ACh). The in vivo chronic neostigmine treatment-related neuromuscular junction degenerative changes are likely due to the direct action of anticholinesterase on the muscle, rather than changes in interstitial acetylcholine levels or presynaptic effects of anticholinesterase. This study used an intraluminal probe equipped with two pairs of electrodes-strain gauges spaced 4 cm apart to investigate the effects of neutral interviews, stress interviews, food intake (478.7 calories), and neostigmine (0.5 mg, intramuscular injection) on the contractile electrical complex, sustained electrical response activity, and related contractions in 17 normal subjects. Neostigmine injection resulted in increases in the contractile electrical complex and sustained electrical response activity indices at 5–10 minutes and 25–30 minutes post-injection, respectively. Both food intake and neostigmine increased the percentage of contractile electrical complex waves propagating throughout all recording periods.

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Therapeutic Uses
Cholinesterase inhibitors; parasympathomimetic drugs
…Anticholinesterase drugs have important value in the treatment of primary glaucoma and certain secondary glaucomas (e.g., aphakic glaucoma, post-cataract extraction glaucoma); congenital glaucoma rarely responds to treatments other than surgery. Primary glaucoma is classified into narrow-angle (acute congestive) and wide-angle (chronic simple) glaucoma… Anticoagulants lower intraocular pressure in both types of glaucoma by reducing resistance to aqueous humor outflow. …In acute congestive glaucoma… anticholinesterase drugs are instilled in combination with parasympathomimetic drugs into the conjunctival sac… In chronic simple glaucoma… and secondary glaucoma, careful consideration of the patient's individual needs is necessary when selecting drugs or drug combinations… Possible drugs include… anticholinesterase drugs… …used to relieve abdominal distension caused by various medical and surgical reasons… Primarily used as an adjunct to the treatment of abdominal distension. When neostigmine is used to treat detrusor muscle weakness, it can relieve postoperative urinary difficulties and shorten the time interval from surgery to spontaneous urination. Neostigmine is also used in the differential diagnosis of myasthenic crisis (which can improve muscle function) and cholinergic crisis (which worsens muscle function), as well as the diagnosis of congenital myotonia.
For more complete data on the therapeutic uses of neostigmine (9 of them), please visit the HSDB record page.
Drug Warnings

Neostigmine must be used with caution in patients with arrhythmias or bronchial asthma.
This product is contraindicated in the presence of mechanical obstruction of the intestine or bladder, peritonitis, or questionable bowel function.
The response to neostigmine in patients with neuromuscular diseases is unpredictable. A 57-year-old female patient with myotonic dystrophy presented with chronic muscle weakness. A 50-year-old male with a 30-year history of progressive muscular dystrophy exhibited a tetanic response to neostigmine during the recovery phase of partial neuromuscular blockade.
Clinical doses of neostigmine can produce acetylcholine-induced blockade, which may pose a potential risk in anesthetic practice. Studies have revealed the effects of neostigmine on 26 patients anesthetized with thiopental sodium and nitrous oxide.
For more complete data on the drug warnings of neostigmine (6 of them), please visit the HSDB record page.

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Pharmacodynamics
Neostigmine is a cholinesterase inhibitor used to treat myasthenia gravis and reverse the effects of muscle relaxants such as galamine and tubocurarine. Unlike physostigmine, neostigmine cannot cross the blood-brain barrier. By inhibiting acetylcholinesterase, more acetylcholine becomes available at the synapse; therefore, more acetylcholine can bind to the fewer receptors present in patients with myasthenia gravis, thus better triggering muscle contraction.

C12H19N2O2+

223.29

223.145

59-99-4

114-80-7 (bromide);51-60-5 (methyl sulfate)

4456

Typically exists as solid at room temperature

1.943

0

2

3

16

246

0

CN(C)C(=O)OC1=CC=CC(=C1)[N+](C)(C)C

ALWKGYPQUAPLQC-UHFFFAOYSA-N

InChI=1S/C12H19N2O2/c1-13(2)12(15)16-11-8-6-7-10(9-11)14(3,4)5/h6-9H,1-5H3/q+1

[3-(dimethylcarbamoyloxy)phenyl]-trimethylazanium

Neostigmine Juvastigmin CCRIS 3079

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.)