This zoonosis —a disease or infection of animals which can be transmitted to humans under natural conditions— annually affects 500,000 people worldwide. This research project forms part of her doctoral thesis, defended at the University’s School of Pharmacy. This study has permitted the development of a new treatment which significantly reduces infections in mice, as opposed to the traditional treatment with “free” (unencapsulated) antibiotics with short treatment times. Despite the fact that brucellosis is highly susceptible to the majority of antibiotics, the indices of relapse in humans ranges from 5 to 15% depending on the antibiotic regimen; in any case, standard treatment requires combined therapy during long periods of time. The alternative treatment developed by Ms. Lecároz involves the transportation of the antibiotic gentamicina to infected cells by means of biodegradable particles, which can produce a much higher concentration of antibiotic precisely in the organs which are infected. These biodegradable systems are designed in such a way that they release the antibiotic in a controlled manner, which allows therapeutic levels of antibiotics after a reduced number of dosages. In this research project, Concepción Lecároz has achieved a significant reduction of spleen pathogens in mice, which has led to the possibility of achieving similar results in humans. In Spain, along with tuberculosis and meningococcal meningitis, brucellosis is one of the most frequent endemic bacterial pathologies. The characteristic symptoms of the disease are fever, chills, weakness, muscular pain, sweating and headaches. If the bacteria invades the bloodstream, it can infect numerous tissues and organs, such as the liver, the spleen, the bones, the genitourinary system, the lungs, the central nervous system, and the heart, to the point of even endangering the life of the patient.