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In vitro and in vivo assessment of the bioavailability of potassium from a potassium tartrate tablet
Author(s) -
Whiting Susan J.,
Gorecki Dennis K. J.,
Jones Dennis
Publication year - 1991
Publication title -
biopharmaceutics and drug disposition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 58
eISSN - 1099-081X
pISSN - 0142-2782
DOI - 10.1002/bdd.2510120305
Subject(s) - potassium , bioavailability , chemistry , excretion , tartrate , zoology , chromatography , pharmacology , biochemistry , medicine , organic chemistry , biology
The bioavailability of potassium from orally administered potassium tartrate was evaluated in 20 normal subjects under metabolic balance conditions. Subjects were given 34 mmol potassium (5 tablets of Cal‐K®) as a divided dose on each of 2 consecutive days. Urinary excretion of potassium, as determined from 24‐h urinary collections on the 3 days preceding dosage totalled 192·6 ± 50·9 mmol (mean ± S.D., n = 20). It increased significantly ( p < 0·05) to 258·7 ± 54·2 mmol for the 2 days of dosage and the following day. The difference of 66.1 mmol representing absorbed potassium was close to the 68 mmol potassium given and indicated a bioavailability of potassium in excess of 97 per cent; after correction for creatinine excretion, potassium recovery rose to 99·9 per cent. The dissolution characteristics of the Cal‐K® tablets were also determined. After dissolution in simulated gastric juice (pH 1·2), 84·4 ± 10·6 per cent (mean ± S.D., 6 experiments) was dissolved; after adjustment to pH 7·3, dissolved potassium increased to 91·3·8·5 per cent. No precipitation or residue formed as a result of the pH change. Both sets of results indicate that potassium from these potassium tartrate tablets is in a highly bioavailable form.