Iron polymaltose complexes: Could we spot physicochemical differences in medicines sharing the same active pharmaceutical ingredient?

Oral iron therapy can efficaciously treat both iron deficiency and iron deficiency anemia. To overcome the recurrent side effects of iron(II) salts, medicines containing iron(III) such as iron polymaltose complex (IPC) have been introduced in several markets. Despite the claimed improved safety versus iron(II) preparations, divergent evidences are currently available on IPC efficacy. Indeed, the use of either an originator drug or a follow-on version ("similar") of this medicine might result in different clinical performances. The aim of this work was the pioneer evaluation of physicochemical properties of IPC vs. iron polymaltose complex similars (IPCSs) as nanomedicines. This, to assess the presence of deviations for commercially available products supposedly containing the same active pharmaceutical ingredient and currently considered as generics. Significant differences with respect to size, size distribution, stability and degradation kinetics of the products are reported here. Therapeutic equivalence of IPC and IPCSs is not proven, and new guidelines are needed to determine whether these nanomedicines can be regarded as interchangeable.