clearances were independent of the nature of the medium ( saline , 0.1 m phosphate buffer , ph 7.4 , or human plasma ) , time ( through 2 hr ) and initial concentration of porphyrin precursor ( 3.0-10.3 mg/l for ala , 1.5-3.6 mg/l for pbg ) .
C2917401
porphyrin precursor
C0002563
ala