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1620262 
Journal Article 
Gas Chromatographic Determination Of The Glucuronide Of 2-(1-Hydroxy-ethyl)-7-(2-hydroxy-3-isopropyl-aminopropoxy)-benzo furan, A Metabolite Of Befunolol, In Human Urine 
Kawahara, K; Ofuji, T 
1983 
1 
Journal of Chromatography
ISSN: 0021-9673 
NIOSH/00146404 
272 
1 
187-192 
A gas chromatographic (GC) method for quantifying a befunolol (39543798) metabolite, 2-(1-hydroxy-ethyl)-7-(2-hydroxy-3-isopropyl-aminopropoxy)-benzofuran and its glucuronide was developed. Their excretion rates (unconjugated) were compared. Two healthy male adult volunteers received oral dose of 20 milligrams befunolol capsule after a 16 hour fast. Urine samples were collected prior and after 1 to 6 hours post treatment. Samples were eluted with water, washed with ethyl-acetate and diethyl-ether, mixed with 6-bromo-2-naphthyl-beta-D-glucuronide as the internal standard (IS) and eluted with methanol from an Amberlite XAD-2 column. Following trimethylsilylation, aliquots of elute were injected into a GC equipped with a flame ionization detector. The glass column was packed with OV-17 on chromosorb. Nitrogen was used as carrier gas at flow rate of 70 milliliter (ml) per minute at 260 degrees-C. The recovery of the glucuronide from the column eluted with water was 97.8 percent while that of the glucuronide and IS from the Amberlite column were 97.5 and 91.7 percent, respectively. The peak ratios indicated that trimethylsilylation of the glucuronide and IS were completed within 10 minutes. Ratios remained stable for 60 minutes and the yields of derivatives were independent of temperature. Derivatives showed retention times of 10.9 and 6.3 minutes, respectively. Calibration curves were linear in the range of 5 to 100 micrograms (microg) per 2ml. Average glucuronide recovery from spiked urine was 101 percent with minimum detection limit of 2.5microg/ml. The excretion rate constant of the metabolite was 0.464 hours for one subject and 0.428 hours for the other subject. The authors conclude that the method for determining this glucuronide in human urine is highly sensitive, specific, and reproducible. 
DCN-133549; Halogenated hydrocarbons; Medical treatment; Clinical chemistry; Medical research; Urinalysis; Analytical chemistry; Analytical methods; Chromatographic analysis; Trace analysis; Laboratory techniques; Physiological chemistry