Analysis of p-aminobenzoic acid and its metabolites in urine and plasma by ion pair HPLC in the NBT-PABA pancreatic function test.

An ion pair HPLC method which can simultaneously detect the major metabolites of an exocrine pancreatic function testing agent (NBT-PABA) in plasma and urine has been developed. This assay has been applied to a pharmacokinetic study of PABA and its metabolites in 3 healthy adult volunteers following the oral administration of 1 g NBT-PABA. The 6 h testing period currently used to collect urine following the NBT-PABA ingestion is adequate for the recovery of PABA and its metabolites. Plasma determination of these compounds may provide an improved evaluation of the pancreatic performance in patients with abnormal liver or kidney function.