Determination, purity assessment and chiral separation of levodopa methyl ester in bulk and formulation pharmaceuticals

2006 ◽  
Vol 20 (9) ◽  
pp. 904-910 ◽  
Author(s):  
Jie Wang ◽  
Yuzhi Fang
Keyword(s):  
Methyl Ester ◽  
Chiral Separation ◽  
Purity Assessment ◽  
Levodopa Methyl Ester

Determination of levodopa methyl ester and its metabolites in rat serum by CZE with amperometric detection

2005 ◽  
Vol 382 (1) ◽  
pp. 198-203 ◽  
Author(s):  
J. Wang ◽  
Y. Zhou ◽  
A. F. Wang ◽  
S. H. Zhang ◽  
L. Ning ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Amperometric Detection ◽  
Rat Serum ◽  
Levodopa Methyl Ester

scholarly journals Development of a Hydrophobicity-Controlled Delivery System Containing Levodopa Methyl Ester Hydrochloride Loaded into a Mesoporous Silica

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1039
Author(s):  
Tamás Kiss ◽  
Gábor Katona ◽  
László Mérai ◽  
László Janovák ◽  
Ágota Deák ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Drug Release ◽  
Mesoporous Silica ◽  
Surface Area ◽  
Release Rate ◽  
Release Kinetics ◽  
Amorphous State ◽  
Ester Hydrochloride ◽  
Methyl Ester Hydrochloride ◽  
Levodopa Methyl Ester

Background: The drug release of antiparkinsonian drugs is an important issue during the formulation process because proper release kinetics can help to reduce the off periods of Parkinson’s disease. A 2-factor, 3-level (32) full-factorial design was conducted to evaluate statistically the influence of the hydrophobicity of mesoporous silica on drug release. Methods: Hydrophobization was evaluated by different methods, such as contact angle measurement, infrared spectroscopy and charge titration. After loading the drug (levodopa methyl ester hydrochloride, melevodopa hydrochloride, LDME) into the mesopores, drug content, particle size, specific surface area and homogeneity of the products were also analyzed. The amorphous state of LDME was verified by X-ray diffractometry and differential scanning calorimetry. Results: Drug release was characterized by a model-independent method using the so-called initial release rate parameter, as detailed in the article. The adaptability of this method was verified; the model fitted closely to the actual release results according to the similarity factor, independently of the release kinetics. Conclusions: The API was successfully loaded into the silica, resulting in a reduced surface area. The release studies indicated that the release rate significantly decreased (p < 0.05) with increasing hydrophobicity. The products with controlled release can reduce the off period frequency.

scholarly journals Controlled-release levodopa methyl ester/benserazide-loaded nanoparticles ameliorate levodopa-induced dyskinesia in rats

2012 ◽  
pp. 2077 ◽  
Author(s):  
Weien Yuan ◽  
Xinxin Yang ◽  
Ruiyuan Zheng ◽  
Yunpeng Cai ◽  
Meiling Liao ◽  
...  
Keyword(s):  
Controlled Release ◽  
Methyl Ester ◽  
Levodopa Methyl Ester

Fluctuating parkinsonism: a pilot study of single afternoon dose of levodopa methyl ester

1996 ◽  
Vol 243 (5) ◽  
pp. 377-380 ◽  
Author(s):  
Fabrizio Stocchi ◽  
Luca Barbato ◽  
Lucia Bramante ◽  
Giampietro Nordera ◽  
Laura Vacca ◽  
...  
Keyword(s):  
Pilot Study ◽  
Methyl Ester ◽  
Levodopa Methyl Ester

scholarly journals A simple procedure for distinguishing dopamine from noradrenaline in peripheral nervous structures in the fluorescence microscope.

1978 ◽  
Vol 26 (2) ◽  
pp. 141-144 ◽  
Author(s):  
A Hess
Keyword(s):  
Methyl Ester ◽  
Sympathetic Ganglion ◽  
Ganglion Cells ◽  
Simple Procedure ◽  
Fluorescence Microscope ◽  
Treatment Results ◽  
Reserpine Treatment ◽  
Sequential Administration ◽  
The Difference ◽  
Levodopa Methyl Ester

The difference between dopamine and noradrenaline after ordinary histofluorescent procedures cannot be discerned. Reserpine treatment results in depletion of fluorescent material from dopaminergic and noradrenergic peripheral nervous structures. Administration of reserpine, 1 mg/kg subcutaneously for 3 hr, followed by intraperitoneal injection of 200 mg/kg levodopa methyl ester on 0.9% saline for 90 min, result in refluorescence of dopaminergic (glomus cells of the carotid body) but not noradrenergic (sympathetic ganglion cells, nerves of atrial heart muscle and blood vessels) structures. Hence, the sequential administration of these readily available drugs and the application of ordinary histofluorescent techniques result in a simple procedure for distinguishing dopamine from noradrenaline in the fluorescence microscope.

JEJUNAL DELIVERY OF LEVODOPA METHYL ESTER

The Lancet ◽  
1989 ◽  
Vol 334 (8653) ◽  
pp. 45-46 ◽  
Author(s):  
Stefano Ruggieri ◽  
Fabrizio Stocchi ◽  
Angelico Carta ◽  
Marco Catarci ◽  
Alessandro Agnoli
Keyword(s):  
Methyl Ester ◽  
Levodopa Methyl Ester

Studies of the Rate Constant of Levodopa Methyl Ester Hydrolysis by LC

2005 ◽  
Vol 62 (7-8) ◽  
pp. 423-428
Author(s):  
J. Wang ◽  
Y. Zhou ◽  
Y. Z. Fang
Keyword(s):  
Methyl Ester ◽  
Rate Constant ◽  
Ester Hydrolysis ◽  
Levodopa Methyl Ester
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