EVALUATION OF THE BIOEQUIVALENCE OF 2 FAS T RELEASING IRON(II) SULFATE FORMULATIONS

Bioequivalence of a new oral iron formulation (A: FE(II)SO4 . H2O, cap sule with 100 mg Fe++, Eryfer 100, CAS 7782-63-0) with the standard fo rmulation (B: Fe(II)SO4 . H2O, capsule with 50 mg Fe++ Eryfer(R)) was demonstrated after administration of 100 mg Fe++ in a single-dose two- way cross-over design to 16 normal female volunteers. Iron concentrati ons were monitored from 24 h before (basal) to 24 h post application. The area under concentration difference curve AUC(diff) and the maxima l concentration difference Cmax(diff) were calculated subtracting the basal from the time-corresponding postabsorptive concentrations. AUC(d iff) (A: 170 nmol/ml . h, B: 168 nmol/l .h) and Cmax(diff) (A: 23.3 nm ol/ml. B: 21.8 nmol/ml) showed but minor differences between formulati ons. The AUC(diff) and C(max) ratio (A/B) and the corresponding 90 % c onfidence intervals, 102 % (74-129 %) and 107 % (91-123 %), were inclu ded by the study protocol. Hence, both formulations were bioequivalent with respect to rate and extent. The ANOVA coefficient of variation o f Cmax(diff) was considerably smaller than that of AUC(diff) (26 % ver sus 44 %). The characteristics based on the post absorptive iron incre ase (post-absorptive concentrations minus concentration preceeding imm ediately application) AUC(pad) (ratio 99 % (83-114 %)) and Cmax(pad) ( ratio 104 % (95-112 %)) exhibited smaller ANOVA-CVs (25 % and 14 %, re spectively) as compared with AUC(diff) and Cmax(diff) All these charac teristics appeared to be rather normal than log-normal distributed. It was concluded that the study design was selective to demonstrate an a dequate bioavailability of iron formulations.