Acetic acid Levodopa

C2H3CIO 75-36-5) see Acebutolol Acetiamine Acetylcholine chloride L-Alanine Benfurodil hemisuccinate . Chlorprothixene Flumetasone Ibuprofen lotalamic acid loxitalamic acid Levodopa Methestrol dipropionate Midecamycin acetate Naproxen Nimesulide Paclitaxel Paramethasone Phensuximide Retinol Rocuronium bromide Rofecoxib Ropinirole Tazarotene Thiopropazate Tiracizine Vecuronium bromide... 

Disposition in the Body. Rapidly absorbed from the small bowel after oral administration and widely distributed in the tissues less than 1% of a dose reaches the brain bioavailability about 33%. Extensively metabolised mainly by decarboxylation to dopamine, which is further metabolised, and also by methylation to 3-0-methyldopa which accumulates in the central nervous system most of a dose is decarboxylated by the gastric mucosa before entering the systemic circulation the decarboxylase activity is inhibited by carbidopa and benserazide. Dopamine is further metabolised to noradrenaline, 3-methoxytyramine, and to the two major excretory metabolites, 3,4-dihydroxyphenyl-acetic acid (DOPAC) and 3-methoxy-4-hydroxyphenylacetic acid (homovanillic acid, HVA). During prolonged therapy, the rate of levodopa metabolism appears to increase, possibly due to enzyme induction. About 70 to 80% of a dose is excreted in the urine in 24 hours. Of the material excreted in the urine, about 50% is DOPAC and HVA, 10% is dopamine, up to 30% is... 

E. Nissinen, and J. Taskinen, Simultaneous determination of carbidopa, levodopa and 3,4-dihydroxyphenyl-acetic acid using high-performance liquid chromatography with electrochemical detection, J. Chromatogr., 1982, 231, 459-462. 

Cimbura and Kofoed (50),mentioned earlier, used GLC to separate amphetamine and methamphetamine after acetylation with acetic anhydride in methanol. Derivatives were extracted using diethyl ether and chromatographed op columns of either 3% OV-17, OV-1, or SE-30. Column temperature was 160°C. They also reported the chromatographic determination of acetylated morphine on 3% SE-30, OV-1, or OV-17 at temperatures of 220°C. Cruickshank et al.(21) separated 21 amino acids as their trifluoroacetylated methyl esters. The column was 5% neopentyl glycol succinate on Gas Chrom P. Column temperatures were both isothermal and programmed 65°C for 20 min at 1.5°C/min then 2°C/min until 42.5 min then 4°C/min until 60 min then isothermal until about 75 min (see Figure 12.2). Chang et al. (19), used BSA/pyridine to form the TMS derivatives of levodopa, methyldopa, tyrosine. 

Levodopa (2-amino-3-(3,4-dihydroxyphenyl)-propanoic acid) (IV) is administered to Parkinson s sufferers to alleviate the reduced levels of dopamine commonly seen in such patients. Dopamine itself is not administered, as this compound cannot cross the blood-brain barrier unlike levodopa which is then converted in the body to dopamine [137]. Bergamini et al. [138] have utilised a gold screen-printed electrode as a sensor for monitoring levodopa both in stationary solution and in flow systems. This was achieved by using the oxidation of levodopa at +0.63 V in acetate buffer pH 3.0. A linear response was reported from 9.9 x 10-5 to 1.2x10 3M and an associated detection limit of 6.8 x 10-5M. The sensor was successfully used to detect the levodopa... 

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