An improved assay by HPLC with amperometric detection for the determination of phentolamine in plasma

J. PéRez-Urizar, P. Aguirre-BañUelos, G. CastañEda-HernáNdez, F. J. Flores-Murrieta

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

An improved method for the determination of phentolamine in human plasma samples was developed. After being alkalinized, plasma samples (1 mL) were extracted with diethyl ether and then back-extracted with O.1 N HCl. Analyses were carried out on a Novapak C8 column eluted with a mixture of sodium monochloroacetate (pH 3) and acetonitrile (75:25). Amperometric detection was performed by oxidation at 1000 mV, using a glassy carbon electrode against Ag/AgCl. Calibration curves, constructed over a 1 to 30 ng/mL plasma concentration range, were linear (r=0.999). Intra-assay coefficients of variation and accuracy for the determined concentrations were comprised within 7.6-10.9% and 94.0-105.6%, respectively. Inter-assay coefficient of variation and accuracy ranges were 10.4-20.7% and 93.2-102.7%, respectively. The method's detection limit was 0.2 ng/mL, allowing determination of oral phentolamine pharmacokinetics after administration of a 40 mg dose. It is concluded that the present procedure is suitable for pharmacokinetic and bioavailability studies of oral phentolamine formulations presently used in the treatment of erectile dysfunction.
Original languageAmerican English
Pages (from-to)557-564
Number of pages500
JournalJournal of Liquid Chromatography and Related Technologies
DOIs
StatePublished - 1 Jan 2000

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Phentolamine
Assays
Pharmacokinetics
High Pressure Liquid Chromatography
Plasmas
Plasma (human)
Glassy carbon
Erectile Dysfunction
Ether
Calibration
Biological Availability
Limit of Detection
Electrodes
Carbon
Sodium
Oxidation

Cite this

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title = "An improved assay by HPLC with amperometric detection for the determination of phentolamine in plasma",
abstract = "An improved method for the determination of phentolamine in human plasma samples was developed. After being alkalinized, plasma samples (1 mL) were extracted with diethyl ether and then back-extracted with O.1 N HCl. Analyses were carried out on a Novapak C8 column eluted with a mixture of sodium monochloroacetate (pH 3) and acetonitrile (75:25). Amperometric detection was performed by oxidation at 1000 mV, using a glassy carbon electrode against Ag/AgCl. Calibration curves, constructed over a 1 to 30 ng/mL plasma concentration range, were linear (r=0.999). Intra-assay coefficients of variation and accuracy for the determined concentrations were comprised within 7.6-10.9{\%} and 94.0-105.6{\%}, respectively. Inter-assay coefficient of variation and accuracy ranges were 10.4-20.7{\%} and 93.2-102.7{\%}, respectively. The method's detection limit was 0.2 ng/mL, allowing determination of oral phentolamine pharmacokinetics after administration of a 40 mg dose. It is concluded that the present procedure is suitable for pharmacokinetic and bioavailability studies of oral phentolamine formulations presently used in the treatment of erectile dysfunction.",
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An improved assay by HPLC with amperometric detection for the determination of phentolamine in plasma. / PéRez-Urizar, J.; Aguirre-BañUelos, P.; CastañEda-HernáNdez, G.; Flores-Murrieta, F. J.

In: Journal of Liquid Chromatography and Related Technologies, 01.01.2000, p. 557-564.

Research output: Contribution to journalArticle

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AU - Flores-Murrieta, F. J.

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