A phase I study was done to evaluate the safety and pharmacokinetics of (L)-2-oxothiazolidine-4-carboxylate (OTZ). An ancillary objective was to compare the effects of treatment with 2 levels of OTZ to placebo on urinary oxalate excretion in healthy male subjects.
Materials and Methods:
Individuals underwent intravenous infusion of 70 (6) or 100 (6) mg./kg. body weight OTZ, or placebo for 2 hours at 4, 8-hour intervals. Urine was collected during the 12 hours before treatment, and at 0 to 4, 4 to 8, 8 to 24, 24 to 28, 28 to 32 and 32 to 48 hours after the initial infusion. Urine samples were assayed for creatinine, oxalate, citrate, sulfate, urate, phosphate and pH.
Urinary oxalate excretion relative to creatinine decreased significantly in the 100 mg./kg. dose group by 4.1 mg./gm. during the first 24 hours and by 4.6 mg./gm. in 24 to 48 hours compared to baseline values (p <0.05). Slight decreases of 0.9 and 1.1 mg./gm., respectively, in the 70 mg./kg. dose group, and 1.6 and 2.3 mg./gm., respectively, in the placebo group were observed. Oxalate excretion on day 2 in the 100 mg./kg. dose group was significantly less than that in the placebo group (p = 0.04). Urinary pH decreased and sulfate excretion increased with OTZ therapy.
Treatment with 100 mg./kg. OTZ every 8 hours decreases urinary oxalate excretion in healthy men.
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From the Department of Urology, Bowman Gray School of Medicine, Winston-Salem, North Carolina and Transcend Therapeutics, Inc., Cambridge, Massachusetts.