Use of N-Acetyl 4-Aminoantipyrine (NAAP) in Measurement of Total Body Water

Abstract

SummaryThe use of N-acetyl 4-amino antipyrine (NAAP) in the measurement of body water has been explored. The substance is uniformly distributed in the various tissues in close proportion to the water content, its metabolism is negligible and it is excreted slowly. The volumes of distribution of anti-pyrine and NAAP were compared in normal human subjects and the values found to agree well. NAAP has certain advantages over antipyrine: it is negligibly bound to plasma proteins; the value for body water may be calculated from a single plasma sample and a urine sample; its colorimetric estimation obviates the need for an ultraviolet spectrophotometer.