Therapeutic isoniazid monitoring using a simple high-performance liquid chromatographic method with ultraviolet detection.
Simultaneous measurement of isoniazid and its main acetylated metabolite acetylisoniazid in human plasma is realized by high-performance liquid chromatography. The technique used is evaluated by a factorial design of validation that proved to be convenient for routine drug monitoring. Plasma samples are deproteinized by trichloroacetic acid and then the analytes are separated on a microBondapak C18 column (Waters). Nicotinamide is used as an internal standard. The mobile phase is 0.05 M ammonium acetate buffer (pH 6)-acetonitrile (99:1, v/v). The detection is by ultraviolet absorbance at 275 nm. The validation, using the factorial design allows one to: (a) test the systematic factors of bias (linearity and matrix effect); (b) estimate the relative standard deviations (RSDs) related to extraction, measure and sessions assay. The linearity is confirmed to be within a range of 0.5 to 8 microg/ml of isoniazid and 1 to 16 microg/ml of acetylisoniazid. This method shows a good repeatability for both extraction and measurement (RSD INH=3.54% and 3.32%; RSD Ac.INH=0.00% and 5.97%), as well as a good intermediate precision (RSD INH=7.96%; RSD Ac.INH=15.86%). The method is also selective in cases of polytherapy as many drugs are associated (rifampicin, ethambutol, pyrazinamide, streptomycin). The matrix effect (plasma vs. water) is negligible for INH (3%), but statistically significant for Ac.INH (11%). The application of this validation design gave us the possibility to set up an easy and suitable method for INH therapeutic monitoring.
Moussa
L Aït
LA
Laboratoire de Toxicologie d'Urgence et de Suivi Thérapeutique, Centre Anti-Poisons du Maroc, Institut National d'Hygiène, Rabat.
Khassouani
C E
CE
Soulaymani
R
R
Jana
M
M
Cassanas
G
G
Alric
R
R
Hüe
B
B
D000995:Antitubercular Agents / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D007538:Isoniazid / Q000097:blood*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*
D000995:Antitubercular Agents; D007538:Isoniazid