Absorption, Distribution and Excretion
In one study, three patients received 50 mg of radiolabeled 14C-benzisazine via intravenous and oral routes, respectively. Three other patients received 50 mg of 14C-benzisazine orally only. Comparison of plasma total radioactivity concentration-time curves between patients receiving oral and intravenous 14C-benzisazine showed that 66% to 74% of the administered dose was absorbed from the gastrointestinal tract. Peak plasma radioactivity was detected in five of the six patients one hour after oral administration. Benzisazine is rapidly excreted in the urine as metabolites, with the majority excreted within the first 6 hours after administration, and 85% of urinary excretion occurring within 12 hours. Radiolabeled 14C-benzisazine is primarily eliminated via urinary excretion; 86% to 90% of the intravenously administered dose was recovered in the urine, while 53% to 64% of the orally administered dose was detectable in the urine. Most of the 14C-benserazide is eventually excreted in the urine within 48 hours after administration. Fecal recovery studies conducted over 5 to 8 days showed that the majority (approximately 30%) of the remaining administered 14C-benserazide was recovered in the feces. Ultimately, benserazide is almost entirely eliminated through metabolism. These metabolites are primarily excreted in the urine (64%), with a small amount excreted in the feces (24%). No readily available data are available regarding the volume of distribution of benserazide. No readily available data are available regarding the clearance rate of benserazide. Metabolites/Metabolites Benserazide is hydroxylated in the intestinal mucosa and liver to trihydroxybenzylhydrazine. Trihydroxybenzylhydrazine is a potent inhibitor of aromatic acid decarboxylases, and it is believed that levodopa in levodopa/benserazide combination formulations is primarily protected from decarboxylation via this benserazide metabolite.

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Biological Half-Life
The half-life of benserazide is recorded as 1.5 hours.

Protein Binding
The protein binding rate of benserazide was observed to be 0%.

[1]. Benserazide is a novel inhibitor targeting PKM2 for melanoma treatment. Int J Cancer. 2020 Jul 1;147(1):139-151.

Benserazide is a carboxylhydrazine compound formed by the condensation of the carboxyl group of DL-serine with the primary amino group of 4-(hydrazylmethyl)benzene-1,2,3-triol. It is an aromatic L-amino acid decarboxylase inhibitor (DOPA decarboxylase inhibitor) that does not enter the central nervous system and is usually used in combination with levodopa in the form of hydrochloride for the treatment of Parkinson's disease. Benserazide increases the amount of levodopa reaching the central nervous system by inhibiting the peripheral conversion of levodopa to dopamine, thereby reducing the required dose. Benserazide alone does not have anti-Parkinson's disease activity. It is both an EC 4.1.1.28 (aromatic L-amino acid decarboxylase) inhibitor and an anti-Parkinson's disease drug and dopaminergic drug. It is a carboxylhydrazine, belonging to the catechol class of compounds, and is a primary amino compound and a primary alcohol. It is the conjugate base of benserazide (1+). When levodopa is used alone to treat Parkinson's disease, it is extensively metabolized into dopamine throughout the body, leading to elevated circulating dopamine levels in the blood and various extracranial tissues. This can cause a range of side effects, such as nausea, vomiting, and even arrhythmias, reducing patient adherence. Therefore, decarboxylase inhibitors like benserazide are effective compounds used in combination with levodopa because they cannot cross the blood-brain barrier on their own, but can prevent levodopa from being converted into dopamine in extracranial tissues, thus minimizing extracranial side effects. Levodopa/benserazide combination preparations are widely used globally to treat Parkinson's disease. Of particular note is that although levodopa/benserazide combination preparations have been formally approved in Canada and most of Europe, the U.S. Food and Drug Administration (FDA) has also approved another similar levodopa/dopa decarboxylase inhibitor combination preparation—levodopa/carbidopa. Furthermore, the European Medicines Agency has granted benserazide orphan drug designation since 2015 because of its potential for treating β-thalassemia. Benserazide is a dopa decarboxylase inhibitor that does not enter the central nervous system. In the treatment of Parkinson's disease, benserazide is often used in combination with levodopa to prevent the peripheral conversion of levodopa to dopamine, thereby increasing the amount of drug reaching the central nervous system and reducing the required dose. When used alone, it does not have an anti-Parkinsonian effect.

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Drug Indications
Currently, the primary therapeutic use of benserazide is in combination with levodopa for the treatment of Parkinson's disease in adults aged 25 years and older, excluding drug-induced Parkinsonian syndromes. At specific doses, the combination of levodopa and benserazide can also be used to treat restless legs syndrome, which is sometimes associated with Parkinson's disease. Some studies have prompted the European Medicines Agency to grant benserazide hydrochloride orphan drug designation as a potential treatment for β-thalassemia. Although related research is ongoing, there is currently no formal evidence.

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Mechanism of Action
The combination of levodopa and benserazide is an anti-Parkinson's drug. Levodopa is a metabolic precursor of dopamine. In Parkinson's disease, dopamine levels in the striatum, globus pallidus, and substantia nigra of the central nervous system (CNS) are significantly reduced. Therefore, levodopa has been proposed as a treatment for the disease to promote increased dopamine levels in these areas. Levodopa is metabolized to dopamine by dopa decarboxylases, but unfortunately, this metabolism also occurs in extracerebral tissues. Therefore, if some levodopa is metabolized outside the CNS, the full therapeutic effect of the administered dose may not be achieved, and the presence of extracerebral dopamine can lead to various extracerebral side effects that reduce patient compliance, such as nausea, vomiting, and even arrhythmias. Therefore, peripheral decarboxylase inhibitors, such as benserazide, can block the extracerebral decarboxylation of levodopa, and their combined use with levodopa offers significant advantages. These benefits include reduced gastrointestinal side effects, faster and more complete efficacy at the beginning of treatment, and a simpler dosing regimen. However, it is worth noting that benserazide is hydroxylated to trihydroxybenzylhydrazine in the intestinal mucosa and liver. Trihydroxybenzylhydrazine, a potent inhibitor of aromatic amino acid decarboxylases, is precisely this metabolite that primarily protects levodopa from decarboxylation and dopamine formation in the intestines and other parts of the body outside the blood-brain barrier. However, since Parkinson's disease progresses even with combined levodopa and benserazide therapy, this combination therapy should only be considered if it improves the quality of life of Parkinson's patients and reduces the adverse effects of such drugs. Switching to or starting this combination therapy is not very meaningful if the patient is already receiving stable, effective, and well-tolerated levodopa monotherapy. Finally, it has been proposed that benserazide hydrochloride may treat β-thalassemia by maintaining the active expression of the fetal hemoglobin gene, thereby allowing the continuous production of fetal hemoglobin to replace the adult hemoglobin variations specific to patients with this disease, thus reducing the need for blood transfusions.

C10H15N3O5

257.2432

257.101

322-35-0

Benserazide hydrochloride;14919-77-8

2327

Typically exists as solid at room temperature

1.541 g/cm3

574.2ºC at 760 mmHg

301ºC

1.678

-1.3

7

7

5

18

278

0

[2H]C(C([2H])(O)[2H])(N)C(NNCC1=C(O)C(O)=C(O)C=C1)=O.Cl

BNQDCRGUHNALGH-UHFFFAOYSA-N

InChI=1S/C10H15N3O5/c11-6(4-14)10(18)13-12-3-5-1-2-7(15)9(17)8(5)16/h1-2,6,12,14-17H,3-4,11H2,(H,13,18)

2-amino-3-hydroxy-N'-[(2,3,4-trihydroxyphenyl)methyl]propanehydrazide

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.)