The aim of the present study was to synthesize crosslinked alginate particles (CAPs) loaded with of iron dextran particles (IDP) using the emulsion-crosslinking technique and evaluate them as a potential intramuscular (IM) prolonged-release iron supplement for mammals as humans and pigs. This method presents a potential solution for IM iron supplementation in mammals, offering a controlled and efficient approach to combat iron deficiency. Multi-vesicular CAPs of 25-30 mu m were developed with ascending IDP content, obtaining similar to 120-200 mg iron/g CAP, distributed mostly in inner and outer layer walls. The encapsulation efficiency, yield and loading capacity values ranged from 22 % to 28 %, 70-76 % and 12-20 %, respectively. IDPs are trapped in alginate-calcium networks without evidence of chemical bonding according to FTIR. XRD analysis suggests a new calcium alginate structure without IDP structural modifications. The release time resulted in 4 h (for commercial iron dextran formulation, CIDF) in contrast with the 120 h observed in the CAP4 formulation. This prolonged release, driven by concentration gradients and hindered by physical barriers, indicates an effective containment and prolonged release of IDP, representing a novel and promising strategy for IM iron supplementation to prevent iron deficiency anemia in mammals, including humans and pigs.