Clinical pharmacokinetics of ferric natural protein in iron-deficient females

Although iron therapy is very common, few studies have assessed iron absorption or iron kinetics in general, particularly with Fe3+. This was the primary objective of this study, with assessment of tolerance as a secondary objective. Eight nonsmoking iron-deficient females without other associated pathologies, with an average age of 21.62 ± 1.69 years, were studied. The diagnosis of iron deficiency was established by determination of sideraemia (28.7 ± 13.5 μg/dl), iron binding capacity (380.5 ± 70.2 μg/dl) and ferritin (5 ± 1.4 yg/L) on the prestudy visit. The women remained in the Phase I Unit during days 0, 1, 2 and 3 of the study. A serum iron concentration curve was obtained daily from blood samples drawn at 0, 1, 2, 4, 6, 8 and 12 hours postdose. Therapy with ferric natural protein (ferrimannitol ovoalbumin) 40 mg twice daily was started on day 1 of the study and continued for 30 days. The following parameters were evaluated: area under the curve (AUC(0-12h)), peak iron concentration (C(max)) and time to reach peak concentration (t(max)). Serum iron concentration-time curves were practically flat on day 0, but showed an increase following ferric therapy (Friedman, p < 0.05), confirming the usefulness of the postabsorption test and good absorption of ferric iron (Fe3+). The increase in AUC (314.65 ± 67.9 to 1174.44 ± 1071.8 (μg/dl·h) and C(max) (49 ± 24.4 to 146 ± 101.9 μg/dl) from day 1 and the correlation between both parameters (r2 > 0.85, p ≤ 0.008) supported the use of either parameter. The t(max) ranged from 4 to 6 hours. Ferric therapy was well tolerated by all patients. This study shows that ferric iron contained in this preparation is well absorbed and provides a satisfactory method for evaluation of iron absorption.