PMID- 11377054
OWN - NLM
STAT- MEDLINE
DCOM- 20011004
LR  - 20190815
IS  - 0731-7085 (Print)
IS  - 0731-7085 (Linking)
VI  - 25
IP  - 5-6
DP  - 2001 Jul
TI  - A direct injection capillary electrophoretic technique for miniaturized 
      high-throughput metabolic screening of the CYP 3A4 enzyme using quinidine as a 
      probe.
PG  - 721-9
AB  - A capillary electrophoresis (CE) method has been developed for the determination 
      of quinidine sulfate (QS) and (3S)-3-hydroxyquinidine (3-OHQ) by direct injection 
      of microsomal incubation mixtures. 3-OHQ is the CYP 3A4 metabolite of QS and 
      hence useful for metabolism screening studies. The method was validated 
      analytically and tested for its effectiveness as a metabolic inhibition model. A 
      linear calibration was found to provide the best fit for the standard curve with 
      an r of 0.9966 and all residuals less than 12%. The percent relative standard 
      deviations (RSDs) of the two controls, 2 and 8 microg/ml were 5.27 and 2.90% and 
      the percent difference from normal (% DFN) were -12.58 and -0.31% respectively. 
      The limit of quantitation (LOQ) in the incubation matrix was 0.5 microg/ml. 3-OHQ 
      formation complied with Michaelis-Menten kinetics and the mean values+/-S.D. of 
      Km and Vmax were 36.98+/-4.62 microg/ml and 321.39+/-3.88 ng/mg/h respectively. 
      Preliminary inhibition studies suggest that the method has adequate sensitivity 
      to screen for high and medium inhibitors of the CYP 3A4 isozyme. The lack of 
      sample preparation coupled with the small sample size capability of CE would 
      enable the direct injection technique to aid in miniaturized high-throughput 
      screening.
FAU - Bhoopathy, S
AU  - Bhoopathy S
AD  - Department of Pharmaceutics, Medical College of Virginia, Virginia Commonwealth 
      University, P.O. Box 980533, Richmond, VA 23298-0533, USA.
FAU - Sarkar, M
AU  - Sarkar M
FAU - Thomas Karnes, H
AU  - Thomas Karnes H
LA  - eng
PT  - Journal Article
PL  - England
TA  - J Pharm Biomed Anal
JT  - Journal of pharmaceutical and biomedical analysis
JID - 8309336
RN  - 9035-51-2 (Cytochrome P-450 Enzyme System)
RN  - EC 1.- (Mixed Function Oxygenases)
RN  - EC 1.14.14.1 (CYP3A protein, human)
RN  - EC 1.14.14.1 (Cytochrome P-450 CYP3A)
RN  - ITX08688JL (Quinidine)
SB  - IM
MH  - Animals
MH  - Cytochrome P-450 CYP3A
MH  - Cytochrome P-450 Enzyme System/*metabolism
MH  - Electrophoresis, Capillary/*methods
MH  - Microsomes, Liver/enzymology
MH  - Miniaturization
MH  - Mixed Function Oxygenases/*metabolism
MH  - Models, Biological
MH  - Quinidine/analysis/*pharmacokinetics
MH  - Rats
MH  - Reproducibility of Results
MH  - Sensitivity and Specificity
MH  - Spectrophotometry, Ultraviolet
EDAT- 2001/05/30 10:00
MHDA- 2001/10/05 10:01
CRDT- 2001/05/30 10:00
PHST- 2001/05/30 10:00 [pubmed]
PHST- 2001/10/05 10:01 [medline]
PHST- 2001/05/30 10:00 [entrez]
AID - S0731-7085(01)00347-8 [pii]
AID - 10.1016/s0731-7085(01)00347-8 [doi]
PST - ppublish
SO  - J Pharm Biomed Anal. 2001 Jul;25(5-6):721-9. doi: 10.1016/s0731-7085(01)00347-8.