Absorption - Oral Bismuth (Bi)
soluble compounds, e.g. bismuth subnitrate, are more readily absorbed.
Many bismuth salts are poorly
absorbed due to their insolubility. It has been suggested that oral Bi
absorption depends on the solubility of the Bi compound in the GI tract
(Billon et al., 1976;
Thomas and al, 1977;
Thomas et al.,
Lechat and Kisch, 1986).
Pharmacologically active Bi
salts were divided into four groups:
Water insoluble organic
salts and sub-salts that are minimally absorbed, and therefore cause
compounds which are sufficiently absorbed to elevate Bi blood levels
and cause neurotoxicity and hepatotoxicity.
which are sufficiently absorbed to elevate Bi blood levels and cause
that hydrolyze in the GI tract resulting in some absorption of Bi
and the hydrolyzed radical, elevating blood levels of Bi and the
(Slikkerveer and de Wolff, 1989).
Bi bioavailability, using
205Bi, was studied in rats. Bioavailability of the citrate
containing compounds (colloidal Bi subcitrate, soluble Bi citrate, and
basic Bi citrate) was significantly higher (0.26-0.33%) than from basic
Bi nitrate, Bi salicylate, Bi gallate and Bi aluminate (0.04-0.11%)
et al., 1991). Intestinal perfusion of rat small intestine with Bi
citrate and colloidal Bi subcitrate resulted in higher Bi concentrations
in the blood than with Bi subnitrate, Bi subsalicylate or Bi chloride
et al., 1995).
Bi bioavailability from
205Bi-labeled compounds given to human volunteers showed the same
trends as in rats, but lower bioavailability: 0.042% of colloidal
bismuth subcitrate, 0.038% of basic bismuth gallate, and 0.002 to
0.005% of basic Bi nitrate, basic Bi subsalicylate, and Bi aluminate
appeared in the urine
et al., 1992).
Although the Bi species that
is absorbed from the intestine is unknown, the absorbed species is
usually not the species that was ingested. Several unidentified Bi
species may form in the intestine, in which the counter-ion has been
suggested to be responsible for absorption.
cysteine and Bi subnitrate administration increased Bi absorption
et al., 1979). Sulfhydryl-group-containing compounds increased the
Bi blood concentration in rats. Cysteine, homocysteine,
3-mercaptopropionic acid and penicillamine produced the greatest
increase. Methionine, serine and alanine did not increase the Bi blood
(Chaleil et al., 1981). Cysteine increased Bi
absorption from Bi subsalicylate in rats. This was not seen when
cysteine was simultaneously given with the Bi salt in a cysteine-rich
(D'Souza and Francis, 1987).
Citrate increased intestinal
absorption of Bi from Bi subnitrate, Bi subsalicylate, Bi citrate, Bi
chloride, and collodial Bi subcitrate given by in vivo perfusion
of the rat small intestine
(Slikkerveer et al., 1992a).
The citrate-enhanced absorption of Bi was reduced by active and passive
transport blockers, suggesting Bi absorption by both transcellular and
(Slikkerveer et al., 1992a).
Simultaneous citrate intake
with Bi subnitrate by human volunteers significantly increased Bi
absorption. The absorption profiles for Bi in blood and citrate in serum
were parallel, suggesting formation and absorption of a Bi citrate
(Slikkerveer et al., 1992b).
The site(s) of Bi absorption
(Slikkerveer and de Wolff, 1996). The bioavailability
of radiolabeled Bi compounds corresponded with their solubility in
artificial duodenal, but not gastric, juice
(Dresow et al.,
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