Determination of anesthetic thiamylal in blood by reversed phase high performance liquid chromatography

• Published in: BUNSEKI KAGAKU Vol. 35; no. 3; pp. 245 - 249
• Main Authors: HIBI, Kiyokatsu, WADA, Akio, TAKEUCHI, Mikio, HATTA, Makoto
• Format: Journal Article
• Language: Japanese; English
• Published: Tokyo The Japan Society for Analytical Chemistry 1986; Japan Science and Technology Agency
• Subjects: depro teinization of serum with acetonitrile; determination of thiamylal in blood; reversed phase high performance liquid chromatography
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.35.3_245

A method was developed for the determination of thiamylal in blood by means of reversed phase high performance liquid chromatography. Two hundred microliters of serum or plasma containing thiamylal was spiked with 60 μl ofn-propyl p-hydroxybenzoate methanol solution (25 mg/100 ml) as an internal standard. Deproteinization of this sample was performed by adding acetonitrile and centrifuging at 4500 r.p.m. for 10 min. The supernatant was filtered with 0.45 μm membrane filter and 20 μ 1 of the filtrate was subjected to reversed phase high performance liquid chromatography. The recovery for thiamylal by this method was 104407%. The sufficient resolution was obtained by using a silica-ODS column, Finepak SIL C18T (250 mm × 4.6 mm i. d.) at 40°C and 10 mM phosphate buffer (pH 3.0)-acetonitrile(50 : 50) as mobile phase with the flow rate of 1.0 ml/min. UV absorption of the effluent was monitored at 288 urn. Thiamylal concentration in serum or plasma was determined by internal standard method, using the peak height ratio of thiamylal peak to n-propyl-phydroxybenzoate peak (I.S.). The detection limit of thiamylal was about 0.6 μg (S/N=3). The precision of the determination by this method was 0.14% as relative standard deviation. This method was successfully applied to the measurement of concentrationtime curve of thiamylal in patient blood. The obtained curve was very useful for optimization of dosage regimen.