Urinary excretion of c-hydroxy derivatives of methaqualone in man.

1. Six monohydroxy metabolites of methaqualone have been identified by g.l.c.-mass spectrometry in the urine of healthy human subjects who received therapeutic doses (250 mg) of the drug (Melsed) daily for ten day. 2. The three major metabolites were 2-methyl-3-(2'-hydroxymethylphenyl)-4(3H)-quinazolinone, 2-methyl-3-(2'-methyl-3'-hydroxyphenyl)-4(3H)-quinazolinone and 2-methyl-3-(2'-methyl-4'-hydroxyphenyl)-4(3H)-quinazolinone. Three minor metabolites in descending order of importance were 2-hydroxymethyl-3-o-tolyl-4(3H)-quinazolinone, 2-methyl-6-hydroxy-3-o-tolyl-4(3H)-quinazolinone and 2-methyl-8-hydroxy-3-o-tolyl-4(3H)-quinazolinone. 3. The 8-hydroxy metabolite is identified as a urinary metabolite or methaqualone in humans for the first time.