The disulphate
ester of ursodeoxycholyl-
p-aminobenzoic acid (
PABA-UCDA) was synthesised and compared with
PABA-UDCA for its use in detection of intestinal bacteria. This compound,
PABA-UDCA disulphate, had characters in common with
PABA-UDCA in that it was deconjugated by
cholylglycine hydrolase to release free
PABA and bacteria that split
glycocholic acid deconjugated
PABA-UDCA disulphate. Further, in rat experiments urinary excretions of
PABA were measured for six hours after
oral administration of 15 mg
PABA-UDCA disulphate. Ten control rats excreted (mean (SE) 188.2 (13.6) micrograms of
PABA; 10 rats with an intestinal stagnant loop excreted more (530.1 (30.1) micrograms; p < 0.001): whereas 10 rats in each of three groups pretreated by
oral administration of various
antibiotics excreted less (polymixin B+tinidazole, 4.9 (1.6) micrograms;
kanamycin, 31.0 (4.7) micrograms;
clindamycin 40.9 (5.5) micrograms; p < 0.001). By contrast with
PABA-UDCA,
PABA-UDCA disulphate was not actively absorbed from any part of the small intestine in everted gut sac experiments, and showed poor recovery from bile after its intraileal instillation in rats. This indicated that
PABA-UDCA disulphate is a single pass type substance in the gut and its
oral administration test reflects the sum of the activities of bacteria in the small intestine and colon. The disulphate was easily soluble in water and this allowed its application in an in vitro test involving
PABA-UDCA disulphate incubation with intraperitoneal
pus (
PABA-UDCA disulphate incubation test) from patients with
peritonitis. This test was carried out on six patients with
peritonitis, and the severity of bacterial
peritonitis was expressed quantitatively. From the results obtained
PABA-UDCA disulphate was considered a good material to detect intestinal bacteria.