High-performance liquid chromatographic assay for morphine in small plasma samples: application to pharmacokinetic studies in rats.
In order to perform a reliable pharmacokinetic study of morphine during subchronic treatment in rats, an easy, rapid, sensitive and selective analytical method was proposed and validated. The analyte and internal standard (naloxone) were extracted from plasma samples (100 microL) by a single solid-phase extraction method prior to reverse-phase high performance liquid chromatography (HPLC) along with electrochemical detection (ED). Standard calibration graphs were linear within a range of 3.5-1,000 ng/mL (r=0.999). The intra-day coefficients of variation (CV) were in the range of 5.8-8.5% at eight concentration levels (7-1,000 ng/mL) and the inter-day coefficient of variation ranged from 7.4 to 8.8%. The intra-day assay accuracy was in the range of -5-10% and the inter-day assay accuracy ranged from 3.0 to 9.3% of relative error (RE). The limit of quantification was 3.5 ng/mL using a plasma sample of 100 microL (15.8% of CV and 12.8% of RE). Plasma samples were stable for 2 months at -20 degrees C. This method was found to be suitable for pharmacokinetic studies in rats, after subcutaneous administration of morphine (5.6 mg/kg per day) in subchronic treatment for 6 and 12 days.
Domínguez-Ramírez
Adriana Miriam
AM
Departamento Sistemas Biológicos, UAM-Xochimilco, Calzada del Hueso 1100, Col. Villa Quietud, 04960 Delegación Coyoacán, México D.F., México. adoming@correo.xoc.uam.mx
Cortés-Arroyo
Alma Rosa
AR
Peña
Marcela Hurtado Y de la
MH
Aoki-Maki
Kazuko
K
López
José Raúl Medina
JR
Ríos-Castañeda
Camilo
C
López-Muñoz
Francisco Javier
FJ
D000701:Analgesics, Opioid / Q000097:blood* / Q000493:pharmacokinetics*; D000818:Animals; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D005260:Female; D007202:Indicators and Reagents; D009020:Morphine / Q000097:blood* / Q000493:pharmacokinetics*; D011786:Quality Control; D051381:Rats; D017208:Rats, Wistar; D012015:Reference Standards; D015203:Reproducibility of Results
D000701:Analgesics, Opioid; D007202:Indicators and Reagents; D009020:Morphine