Dopamine receptor
Melevodopa targets the dopaminergic system in the brain. As a prodrug, it is converted to levodopa, which is then decarboxylated to dopamine, the active neurotransmitter. Dopamine acts on dopamine receptors to exert its therapeutic effects in Parkinson's disease. It is a potent competitive antagonist for the action of L-DOPA. Its recognition site differs from presynaptic beta-adrenoceptors.

Methyl-L-DOPA, an antihypertensive agent, has significant in vitro activity against a variety of atypical mycobacteria such as the Mycobacterium avium complex, M. scrofulaceum, M. xenopi and M. marinum, and rare pathogens like M. fortuitum. In the present investigation, the screening of the in vitro activity was further extended by testing the in vitro activity against a total of 53 different strains of mycobacteria, including 34 clinical isolates of both drug-sensitive and drug-resistant Mycobacterium tuberculosis. Most of the strains were inhibited at 10-25 microg/mL concentrations of the drug[1].
In vitro, melevodopa is a potent competitive antagonist for the action of L-DOPA. It is converted to levodopa in cell-based assays. Its activity is characterized by its ability to increase dopamine levels in neuronal cell cultures. It may also exert anti-tumor functions in leukemia and melanoma.

When methyl-L-DOPA was injected into male mice at a concentration of 10 microg/g body weight (20 g each), methyl-L-DOPA significantly protected them when challenged with a 50 median lethal dose of M. tuberculosis H37Rv102. According to the chi2 test, the in vivo data were highly significant (p<0.01)[1].

---

In the present study, we aimed to assess the potential anti-amblyopic effects of L-dopa methyl ester (LDME) on visual cortex area 17 in an amblyopic feline model induced by monocular vision deprivation. After LDME administration, pathophysiologic and ultrastructural observations were utilized to examine the morphological changes of nerve cells in visual cortex area 17. Dopamine (DA) and its metabolite contents in visual cortex area 17 were investigated through HPLC analysis. Apoptotic cells in visual cortex area 17 were evaluated by TUNEL assay. Additionally, the c-fos expression both at gene and protein levels was assessed using RT-PCR and immunohistochemistry analyses, respectively. The contents of DA and its metabolites were elevated in visual cortex area 17. Neuronal rejuvenation which occurred in visual cortex area 17 was observed through anatomical and physiological assessments. Similarly, TUNEL results showed that neuronal apoptosis was inhibited in the visual cortex of amblyopic cats by both L-dopa and LDME therapies. Meanwhile, the c-fos expression was notably up-regulated at both the mRNA and protein levels by the treatments. These findings suggested that LDME treatment could effectively increase DA and its metabolite contents, and restrain the apoptotic process, as well as elevate the c-fos expression in nerve cells of visual cortex area 17. Taken together, LDME might ameliorate the functional cytoarchitecture in visual cortex area 17 through mechanisms that elevate DA content and increase endogenous c-fos expression, as well as inhibit neuronal lesion in visual cortex tissue[2].
In vivo, melevodopa is an orally active prodrug that is rapidly converted to levodopa. It is used to treat Parkinson's disease. Its anti-allodynic effects have been observed in animal models. It improves motor function in patients with Parkinson's disease by increasing dopamine levels in the brain. Its faster absorption compared to levodopa may provide a more rapid onset of action.

In vitro enzyme/receptor binding studies for melevodopa are not typical, as its mechanism is as a prodrug. Its conversion to levodopa can be assessed by measuring dopamine production in the presence of DOPA decarboxylase. Receptor binding studies may be performed with dopamine receptors using radioligand binding assays to confirm the activity of the converted product.

In vitro cellular assays for melevodopa involve culturing neuronal cell lines in the presence of the compound. The conversion to levodopa and subsequently to dopamine is measured by HPLC or ELISA. Cell viability is assessed using standard assays. Its effects on dopamine receptor signaling may be studied using reporter assays or by measuring downstream signaling molecules.

A total of 90 kittens (2-week-old) with weights ranging from 200 to 300 g were purchased from the Medical Laboratory Animal Center of Guangxi Medical University, China (Certificate No. SCXK-Gui-2010-0001). The normality of extraocular areas, refracting media and eye fundus was confirmed by routine eye examinations. Cats were randomly assigned into six groups with 15 animals in each group as follows: normal control group, model control group, positive control group and three treatment groups with low-, moderate- and high-doses of LDME. In order to induce amblyopia, left eyelids of all cats except those in the normal control group were sutured following the classic method (Hubel and Wiesel, 1970). After 12 weeks, cats in the LDME treatment groups were intragastrically perfused with 20, 40 and 80 mg/kg LDME dissolved in physiological saline for 30 consecutive days, respectively. In parallel, cats in the positive control group were administered with 40 mg/kg l-dopa, whereas the same volume of normal saline was given to those in the normal and model control groups. All animal protocols were according to the US guidelines (NIH publication #85-23, revised in 1985) for laboratory animal use and care.[2]
In vivo animal studies for melevodopa are conducted in rodent models of Parkinson's disease, such as the 6-OHDA-lesioned rat model. Animals are treated with melevodopa via oral or intraperitoneal administration. Motor function is assessed using tests such as the rotarod, open field, or apomorphine-induced rotation. Brain dopamine levels are measured to confirm target engagement.

Pharmacokinetic properties of melevodopa include its rapid absorption and conversion to levodopa. It has a molecular weight of 247.68 and a molecular formula of C₁₀H₁₄ClNO₄. It is highly soluble, which allows for faster absorption compared to levodopa. It is available as an effervescent formulation. Detailed pharmacokinetic parameters are available from clinical studies.

Toxicological data for melevodopa are similar to those of levodopa. Common side effects include nausea, vomiting, dyskinesias, and psychiatric effects. Long-term use may be associated with motor fluctuations and dyskinesias. It is contraindicated in patients with narrow-angle glaucoma, malignant melanoma, and in combination with non-selective MAO inhibitors. It should be used with caution in patients with peptic ulcer disease.

[1]. In vitro and in vivo antimycobacterial activity of an antihypertensive agent methyl-L-DOPA. In Vivo . 2005 May-Jun;19(3):539-45.
[2]. L-dopa methyl ester attenuates amblyopia-induced neuronal injury in visual cortex of amblyopic cat. Gene . 2013 Sep 15;527(1):115-22.

LDME can increase dopamine levels in the visual cortex. LDME therapy can inhibit neuronal apoptosis. LDME can increase the expression of endogenous c-fos in the visual cortex. LDME can reduce neuronal damage in the visual cortex. LDME is a potential candidate drug for the treatment of amblyopia. [2]
Melevodopa hydrochloride is a prodrug of levodopa used for the treatment of Parkinson's disease. It is also known as L-DOPA methyl ester and is marketed under the trade name Levomet. Its enhanced solubility allows for faster absorption and a more rapid onset of action compared to levodopa. It is available for research purposes and is not approved for human therapeutic use in all jurisdictions.

C10H14CLNO4

247.68

247.061

C, 48.50; H, 5.70; Cl, 14.31; N, 5.66; O, 25.84

1421-65-4

1421-65-4 (HCl);7101-51-1;

10131132

Typically exists as solid at room temperature

1.322g/cm3

384.4ºC at 760mmHg

186.3ºC

1.86E-06mmHg at 25°C

1.642

4

5

4

16

222

1

Cl[H].O(C([H])([H])[H])C([C@]([H])(C([H])([H])C1C([H])=C([H])C(=C(C=1[H])O[H])O[H])N([H])[H])=O

WFGNJLMSYIJWII-FJXQXJEOSA-N

InChI=1S/C10H13NO4.ClH/c1-15-10(14)7(11)4-6-2-3-8(12)9(13)5-6;/h2-3,5,7,12-13H,4,11H2,1H3;1H/t7-;/m0./s1

methyl (2S)-2-amino-3-(3,4-dihydroxyphenyl)propanoate;hydrochloride

ST-41769; ST 41769; (S)-Methyl 2-amino-3-(3,4-dihydroxyphenyl)propanoate hydrochloride; L-3,4-Dihydroxyphenylalanine methyl ester hydrochloride; Melevodopa hydrochloride; L-Dopa methyl ester hydrochloride; levodopa methyl ester hydrochloride; Methyl L-DOPA hydrochloride; L-Tyrosine, 3-hydroxy-, methyl ester, hydrochloride (1:1); Melevodopa hydrochloride

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.

---

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).

View More

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)

---

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).

View More

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

---

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.

---

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