Liquid chromatographic determination of a new catechol-O-methyltransferase inhibitor, entacapone, and its Z-isomer in human plasma and urine

Karlsson, MariAnne; Wikberg, Tom

doi:10.1016/0731-7085(92)80085-2

Cited by 38 publications

(30 citation statements)

References 10 publications

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“…Serum and striatal homogenate concentrations of entacapone and tolcapone after intravenous administration were determined according to the method described by Karlsson and Wikberg (1992) for entacapone. Only minor modifications were made in the sample volumes.…”

Section: Determination Of Entacapone and Tolcapone Concentrations In mentioning

confidence: 99%

Pharmacokinetics and Pharmacodynamics of Entacapone and Tolcapone after Acute and Repeated Administration: A Comparative Study in the Rat

Forsberg

Lehtonen²,

Heikkinen³

et al. 2003

J Pharmacol Exp Ther

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Two catechol-O-methyltransferase (COMT) inhibitors, entacapone and tolcapone, were compared in the rat to elucidate the actual differences between their pharmacokinetics and pharmacodynamics after single and repeated administration. Their inhibitory potencies were also compared in vitro. After intravenous administration (3 mg/kg), the elimination half-life (t 1/2␤ ) of entacapone (0.8 h) was clearly shorter than that of tolcapone (2.9 h). The striatum/serum ratio of tolcapone was 3-fold higher than that of entacapone. After a single oral dose (10 mg/kg), both entacapone and tolcapone produced an equal maximal degree of COMT inhibition in peripheral tissues, but tolcapone inhibited striatal COMT more effectively than did entacapone. After the 7-day treatment (10 mg/kg twice daily), COMT activity had recovered to a level of 67 to 101% of control within 8 h after the last dose of entacapone. In tolcapone-treated animals, there was still extensive COMT inhibition present in peripheral tissues, and the degree of inhibition was higher than that attained after a single dose. The pharmacokinetic-pharmacodynamic modeling revealed that a plateau of COMT inhibition near the maximal attainable inhibition was reached already by plasma concentrations below 2000 ng/ml, both with entacapone and tolcapone. Entacapone and tolcapone inhibited equally rat liver COMT in vitro with K i values of 10.7 and 10.0 nM, respectively. In conclusion, tolcapone has a longer duration of action and a better brain penetration than entacapone. The results also suggest that peripheral COMT is inhibited continuously when tolcapone is dosed at 12-h intervals, but this was not seen with entacapone.The second-generation catechol-O-methyltransferase (COMT, EC 2.1.1.6) inhibitors, entacapone and tolcapone, are indicated as adjuncts to standard levodopa-dopa decarboxylase inhibitor therapy in Parkinson's disease. They increase the bioavailability of levodopa by inhibiting its peripheral metabolism to an inactive metabolite, 3-O-methyldopa. COMT inhibitors improve the efficacy of the levodopa-dopa decarboxylase inhibitor therapy by prolonging the duration of action and the clinical benefit of levodopa (Mä nnistö and Kaakkola, 1999;Kaakkola, 2000).Entacapone and tolcapone apparently behave differently both in experimental animals and humans. However, as a rule, entacapone and tolcapone have been studied only individually; their pharmacokinetics and pharmacodynamics have not been compared thoroughly after single and repeated dosing. Actually, very little is known about their pharmacodynamics in different tissues after repeated dosing. Furthermore, only the relationship between the plasma drug concentration and COMT activity in erythrocytes has been studied previously (Dingemanse et al., 1995(Dingemanse et al., , 1996Forsberg et al., 2002).A few available studies on entacapone and tolcapone in rats suggest that entacapone is eliminated faster than tolcapone and its oral bioavailability is lower than that of tolcapone. After intravenous administration ...

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Section: Determination Of Entacapone and Tolcapone Concentrations In mentioning

confidence: 99%

Pharmacokinetics and Pharmacodynamics of Entacapone and Tolcapone after Acute and Repeated Administration: A Comparative Study in the Rat

Forsberg

Lehtonen²,

Heikkinen³

et al. 2003

J Pharmacol Exp Ther

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“…In the first method good separation of glucuronides was achieved with 20mM-ammonium acetate as separation solution at pH 6.84 3 . In the second method detection was achieved at 335nm 4 Three HPLC methods for the determination of entacapone were reported, the first one determine entacapone and its Z-isomer in human plasma and urine on LiChrosorb C18 column fitted with a micro Bondapak C-18 guard column 5 . The second method determine it in plasma using internal standard rofecoxib.…”

Section: Introductionmentioning

confidence: 99%

Determination of Antiparkinsonism Drug Entacapone

Mohamed

2010

J. Chil. Chem. Soc.

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Spectrophotometric procedures are presented for the determination of the antiparkinsonism drug entacapone. The first method based on the formation of a coloured complex of entacapone with ferric chloride in ethanolic solutions. The coloured product is quantified spectrophotometrically at 665nm.The other Spectrophotometric method determine entacapone in presence of levodopa and carbidopa (which formulated with entacapone in stalevo tablets) by measuring the UV absorbance of entacapone either in zero order at 391nm or in the first order by measuring the amplitude between 360nm and 402nm without any interference from levodopa and carbidopa.HPLC method is described for the separation and determination of entacapone, levodopa and carbidopa on Luna CN 150 x 4.6 column with UV detection at 390nm for entacapone and at 280nm for both levodopa and carbidopa

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“…1 Several techniques such as, Amperometry and Liquidchromatography (LC) methods have been reported in the literature for the quantitative estimation of EA in pharmaceutical 3 and biological fluids. 2,[4][5][6][7][8][9] Moreover, Amperometry involves a tedious extraction procedure involving too many steps. This may result inaccurate and imprecise results because of co-precipitation.…”

Section: Introductionmentioning

confidence: 99%

“…This may result inaccurate and imprecise results because of co-precipitation. 9 Entacapone was quantified in human plasma using a HPLC-UV. 4 They observed a good linearity between the concentration range of 25.0 -2500.00 ng/mL.…”

Section: Introductionmentioning

confidence: 99%

Quantification of Entacapone in Human Plasma by HPLC Coupled to ESI-MS/MS Detection: Application to Bioequavalence Study

Reddy.¹,

Baburao.²,

Chandrasekhar³

et al. 2010

Journal of the Korean Chemical Society

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Liquid chromatographic determination of a new catechol-O-methyltransferase inhibitor, entacapone, and its Z-isomer in human plasma and urine

Cited by 38 publications

References 10 publications

Pharmacokinetics and Pharmacodynamics of Entacapone and Tolcapone after Acute and Repeated Administration: A Comparative Study in the Rat

Pharmacokinetics and Pharmacodynamics of Entacapone and Tolcapone after Acute and Repeated Administration: A Comparative Study in the Rat

Determination of Antiparkinsonism Drug Entacapone

Quantification of Entacapone in Human Plasma by HPLC Coupled to ESI-MS/MS Detection: Application to Bioequavalence Study

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