Immunoaffinity extraction of 4-hydroxy-2-(4-methylphenyl)benzothiazole and its metabolites for determination by gas chromatography-mass spectrometry.
Immunoaffinity extraction of 4-hydroxy-2-(4-methylphenyl)benzothiazole and its metabolites, together with the corresponding meta-isomers has been achieved by the use of an antibody raised against an immunogen, an O-carboxymethyloxime-bovine serum albumin conjugate of 4-hydroxy-2-(4-formylphenyl)benzothiazole. The antibody produced exhibited a broad spectrum of affinity, not only for metabolites oxidized at the 4-methyl group of the benzene moiety but also for the corresponding meta-isomers. Up to 4 micrograms in total of these benzothiazoles could be extracted on the immunoaffinity adsorbent and recovered almost quantitatively by elution with 90% methanol. The resulting chromatogram was free from any interference. The eluted compounds were derivatized by conversion to their methyl esters and/or trimethylsilyl ethers, and subsequently separated into individual benzothiazoles by means of gas chromatography-mass spectrometry. The derivatized compounds were monitored using a characteristic ion, [M-CH3]+., and the limit of detection was 10 fmole. The peak height ratio of each metabolite to its corresponding meta-isomer internal standard was plotted against the concentration of the former and good linearity was observed over the range 0.2-5 ng/ml.
Awata
N
N
Product Research and Development Laboratories, Pharmaceuticals Research Center, Kanebo Ltd., Osaka, Japan.
Toba
F
F
Ando
M
M
Shimada
H
H
Miyairi
S
S
Kato
T
T
Goto
J
J
Nambara
T
T
D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D000915:Antibody Affinity; D052160:Benzothiazoles; D002138:Calibration; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007124:Immunoenzyme Techniques; D007164:Immunosorbents; D012015:Reference Standards; D013237:Stereoisomerism; D013844:Thiazoles / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification
D000894:Anti-Inflammatory Agents, Non-Steroidal; D052160:Benzothiazoles; D007164:Immunosorbents; D013844:Thiazoles; C083638:4-hydroxy-2-(4-methylphenyl)benzothiazole