The aim of the study was the development of analytical methods suitable for the quantification of ldopa,carbidopa and entacapone in plasma of Parkinsonian patients treated with Stalevo®. The metabolite3-O-methyldopa was also determined to obtain some indications on the pharmacokinetics of l-dopa.For the simultaneous analysis of l-dopa, 3-O-methyldopa and carbidopa, a RP C18 column as the stationaryphase and a mixture of methanol and a pH 2.88 phosphate buffer (8:92, v/v) as the mobile phasewere used. A feasible plasma pre-treatment based on protein precipitation was implemented, obtainingextraction yield higher than 94% for all the analytes. For the analysis of entacapone a RP C8 column anda mixture of methanol, acetonitrile and a pH 1.90 phosphate buffer as the mobile phase (17.5:22.5:60,v/v/v) were used. A plasma pre-treatment procedure was developed, based on solid phase extraction ofentacapone using Oasis HLB cartridges. Extraction yields were good, being always higher than 96%.Both methods, based on HPLC–ED (V = +0.8 V), have been fully validated. Good linearity was obtainedover the following concentration ranges: 100–4000 ngmL−1 for l-dopa, 200–10,000 ngmL−1 for 3-Omethyldopa,25–4000 ngmL−1 for carbidopa and 20–4000 ngmL−1 for entacapone. Precision data weresatisfactory, being R.S.D.% values lower than 5.64%; accuracy also resulted very good with recovery datahigher than 90%. The proposed methods have been successfully applied to the analysis of patient plasmasamples and seem to be suitable for therapeutic drug monitoring purposes.

Determination of l-dopa, carbidopa, 3-O-methyldopa and entacapone in human plasma by HPLC-ED

BUGAMELLI, FRANCESCA;MARCHESELLI, CHIARA;RAGGI, MARIA AUGUSTA
2011

Abstract

The aim of the study was the development of analytical methods suitable for the quantification of ldopa,carbidopa and entacapone in plasma of Parkinsonian patients treated with Stalevo®. The metabolite3-O-methyldopa was also determined to obtain some indications on the pharmacokinetics of l-dopa.For the simultaneous analysis of l-dopa, 3-O-methyldopa and carbidopa, a RP C18 column as the stationaryphase and a mixture of methanol and a pH 2.88 phosphate buffer (8:92, v/v) as the mobile phasewere used. A feasible plasma pre-treatment based on protein precipitation was implemented, obtainingextraction yield higher than 94% for all the analytes. For the analysis of entacapone a RP C8 column anda mixture of methanol, acetonitrile and a pH 1.90 phosphate buffer as the mobile phase (17.5:22.5:60,v/v/v) were used. A plasma pre-treatment procedure was developed, based on solid phase extraction ofentacapone using Oasis HLB cartridges. Extraction yields were good, being always higher than 96%.Both methods, based on HPLC–ED (V = +0.8 V), have been fully validated. Good linearity was obtainedover the following concentration ranges: 100–4000 ngmL−1 for l-dopa, 200–10,000 ngmL−1 for 3-Omethyldopa,25–4000 ngmL−1 for carbidopa and 20–4000 ngmL−1 for entacapone. Precision data weresatisfactory, being R.S.D.% values lower than 5.64%; accuracy also resulted very good with recovery datahigher than 90%. The proposed methods have been successfully applied to the analysis of patient plasmasamples and seem to be suitable for therapeutic drug monitoring purposes.
F. Bugamelli; C. Marcheselli; E. Barba; M.A. Raggi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/94703
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