Utilization of titanium oxide-like compound as an inorganic phosphate adsorbent for the control of serum phosphate level in chronic renal failure

Hyperphosphatemia adversely affects the prognosis of patients with chronic renal
failure (CRF). We synthesized a titanium oxide-like compound (TAP) as a phosphate
adsorbent for treatment of hyperphosphatemia in CFR patients. We evaluated the ability
of TAP to adsorb inorganic phosphate in vitro and in vivo. TAP was shown to contain
sulfate and hydroxyl groups by thermal analysis, which probably involved in phosphate
adsorption through an ionic exchange mechanism. TAP constantly adsorbed phosphate
(66.20-72.84 mg/g TAP) over a wide pH range (1.22-7.27) in vitro. To evaluate the phosphate
binding potential of TAP in vivo, adenine-induced CRF rats were fed AIN-76 diet
containing 3% TAP, 10% TAP, 3% sevelamer hydrochloride (clinical phosphate adsorbent),
or 3% calcium carbonate, and serum levels of phosphate and calcium and urinary phosphate
were compared with those in untreated CRF rats. Orally administered TAP showed
the inhibitory effect on serum phosphate level in adenine-induced CRF rats, which was
equivalent to that of sevelamer hydrochloride. These results indicate that TAP is a useful
alternative phosphate-binder with fewer side effects than sevelamer hydrochloride
and calcium carbonate.

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