Biliary excretion of bisacodyl and picosulphate in man: studies in gallstone patients after biliary tract surgery

Studies on laxatives: biliary and urinary excretion in rats given danthron by intravenous infusion or gastric intubation

Rats were infused with danthron (I) at doses of 0.48, 2.2 and 5.8 mumol/100 g body weight, or given 12 mumol/100 g with gastric tube. TLC of bile and urine demonstrated a number of metabolites, at both administration routes. These included I monosulphate (II) and -glucuronide (III), two other phase 2 metabolites which behaved as the corresponding diconjugates, and several phase 1 metabolites (IV) in conjugated form. IV as a group were estimated by photometry of hydrolysed samples, using I as a reference. Danthron conjugates as a group were determined in such samples by a specific method for I. Moreover, II and III were determined individually in unhydrolysed specimens. Following infusion, about 80% of the danthron conjugates in bile were excreted after 1 hour; the dose fractions found after 5 hours represented about 20%, 30%, and 40% at the low, intermediate and high dose level, respectively. The corresponding fractions in urine were 16%, 12% and 10%, giving rise to bile:urine excretion ratios of 1.3, 2.7 and 4.0, respectively. This change in excretion pattern was associated with changes in metabolite muster, which involved a decrease in the balance of IV:I conjugates, as well as an increase in III:II ratio. IV was more abundantly present in bile than in urine, and showed a more sustained excretion than the I conjugates. By intragastric administration, the cumulated excretion (bile + urine) of I conjugates were only 6%, 8% and 5% of dose, in three consecutive 6 hours' periods (0-6, 6-12 and 12-18 hours after dosing). The bile:urine excretion ratios seemed to decrease with time, as did the III:II ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Uptake, conjugation and transport of laxative diphenols by everted sacs of the rat jejunum and stripped colon

Phenolphthalein (PHEN), desacetylbisacodyl (DES) and oxyphenisatin (OXY) were incubated with everted sacs of the rat jejunum and stripped descending colon; the mucosal and serosal fluid were analysed with respect to free and conjugated diphenol by means of HPLC. Conjugates were measured as the amount of free diphenol in completely hydrolyzed samples less the amount before hydrolysis. A study with double-sided administration of PHEN revealed that diphenol uptake from and conjugate output to both sides followed a rectilinear course for 15-90 min. A standard incubation time of 60 min. was chosen for the subsequent experiments, in which the diphenols were administered at the mucosal side at a low and a high concentration. Diphenol uptake, i.e. the amount of free diphenol administered less the amount recovered at the mucosal side, varied in an order (PHEN greater than DES greater than OXY) which seems to be inversely related to the order of water solubility of the compounds. Tissue accumulation and conjugate output relative to uptake varied with the dose, and from one compound to another. At low initial concentration (20 nmol/ml), the compounds were transferred to the jejunal and colonic serosal fluid almost entirely as conjugates (greater than or equal to 95%); the transfer rates followed, qualitatively, the same order as above. In jejunum, more conjugates were released to the mucosal than to the serosal side; in colon the distribution was reversed. Increasing the dose to 100 nmol/ml caused a corresponding increase in uptake, but relative output decreased and tissue accumulation increased; thus demonstrating capacity limitation. With PHEN, the ratio of conjugated:free diphenol on the serosal side remained essentially unchanged; with DES in particular, but also with OXY the ratio decreased. These findings may be interpreted to mean that in case of PHEN capacity limitation is linked to conjugate efflux, while DES and OXY may be poor substrates for glucuronide formation as well. Experiments with serosal side administration like the double-sided PHEN experiments verified the dissimilar conjugate distribution in jejunal and colonic sacs; the phenomenon is to some extent discussed in the text. Identity tests gave evidence that the conjugates were mainly monoglucuronides.

Intestinal handling of bisacodyl and picosulphate by everted sacs of the rat jejunum and stripped colon

Bisacodyl (BIS) is the acetic acid di-ester of the laxative diphenol 2-(4,4'-dihydroxydiphenyl)methyl-pyridine. A HPLC-method which permits the simultaneous determination of BIS and its monodesacetylated (MONO) as well as totally desacetylated (DES) form, has been used to study the intestinal handling of BIS (20 nmol/ml), when the compound was incubated for 60 min. at the mucosal side of the preparations specified. In the jejunal mucosal fluid, BIS disappeared completely in short time, and there was a nearly equivalent rise in DES. MONO was transitory present. Hydrolysis was also rapid in mucosal fluid which had been in contact with jejunal sacs for 30 sec., but BIS was stable in blank incubations. Hydrolysis of BIS was slower by colonic than by jejunal sacs, and all three molecular forms were present during incubation. It seemed still slower in mucosal fluid which had been in contact with colonic sacs for 5 min. BIS just as DES accumulated in the jejunal and colonic serosal fluid mainly as conjugates (greater than 95%), and DES was in all cases the only unconjugated metabolite present. Drug accumulation in jejunal serosal fluid was the same whether BIS or DES was added. However, more drug seemed to accumulate on the serosal side of colonic sacs when incubated with BIS instead of DES. In similar experiments with picosulphate, which is the sulphuric acid di-ester analogue of BIS, free DES was not detected in the mucosal fluid during incubation. The amounts of laxative accumulating in the serosal fluid were less than 1/10 of those observed with BIS.

Interaction between diphenolic laxatives and intestinal bacteria in vitro

The ability of the laxative diphenols desacetylbisacodyl, oxyphenisatin, and phenolphthalein to inhibit growth and cause leakage of potassium ion from microbial cells in vitro was studied with 25 aerobic and 25 anaerobic bacterial strains. None of the aerobes, but some of the anaerobes showed growth inhibition. Potassium release assayed by flame photometry was observed in strains which showed growth inhibition, but also in other strains including anaerobes and aerobes. The highest antibacterial activity among the diphenols was observed with phenolphthalein and the least with desacetylbisacodyl; this relationship as noted for both growth inhibition and potassium release. Enzymatic hydrolysis of picosulphate to the free diphenol desacetylbisacodyl carried out by three strains of anaerobic bacteria was indicated by high pressure liquid chromatography.