Gas chromatographic assay for estazolam in human plasma and results of a bioequivalence study.
This paper describes a new sensitive gas chromatographic method with electron capture detector to assay estazolam in human plasma, which has been developed and validated for pharmacokinetic purposes. The drug and the internal standard (triazolam) were extracted from plasma buffered at pH 9.0 into toluene and analysed on a widebore DB 17 column. The calibration curve covered the 1.0-200 ng ml-1 range with a mean determination coefficient of 0.9996. The quantification limit was 1.0 ng ml-1. This method was used to investigate the bioequivalence of a new formulation of estazolam in drops (test) and the formulation in tablets (reference, ESILGAN). Both formulations were administered at a single dose of 2 mg in a clinical trial carried out on 24 healthy volunteers consisting of 12 males and 12 females, following a crossover randomised design in two periods with wash-out. The test and the reference formulations proved to be fully bioequivalent according to operating guidelines, namely through 90% confidence intervals in the 0.80-1.25 range.
Dal Bo
L
L
IPAS S.A., Clinical Pharmacology Department, Ligornetto, Switzerland.
Verga
F
F
Marzo
A
A
La Commare
P
P
De Vito
M L
ML
D000328:Adult; D014151:Anti-Anxiety Agents / Q000097:blood*; D002138:Calibration; D002849:Chromatography, Gas; D018592:Cross-Over Studies; D004949:Estazolam / Q000097:blood*; D005260:Female; D018757:GABA Modulators / Q000097:blood; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012996:Solutions; D013607:Tablets; D013810:Therapeutic Equivalency; D014229:Triazolam / Q000097:blood
D014151:Anti-Anxiety Agents; D018757:GABA Modulators; D012996:Solutions; D013607:Tablets; D014229:Triazolam; D004949:Estazolam