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by Keyword: Targeted drug delivery


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Marques, J., Valle-Delgado, J. J., Urbán, P., Baró, E., Prohens, R., Mayor, A., Cisteró, P., Delves, M., Sinden, R. E., Grandfils, C., de Paz, J. L., García-Salcedo, J. A., Fernàndez-Busquets, X., (2017). Adaptation of targeted nanocarriers to changing requirements in antimalarial drug delivery Nanomedicine: Nanotechnology, Biology, and Medicine 13, (2), 515-525

The adaptation of existing antimalarial nanocarriers to new Plasmodium stages, drugs, targeting molecules, or encapsulating structures is a strategy that can provide new nanotechnology-based, cost-efficient therapies against malaria. We have explored the modification of different liposome prototypes that had been developed in our group for the targeted delivery of antimalarial drugs to Plasmodium-infected red blood cells (pRBCs). These new models include: (i) immunoliposome-mediated release of new lipid-based antimalarials; (ii) liposomes targeted to pRBCs with covalently linked heparin to reduce anticoagulation risks; (iii) adaptation of heparin to pRBC targeting of chitosan nanoparticles; (iv) use of heparin for the targeting of Plasmodium stages in the mosquito vector; and (v) use of the non-anticoagulant glycosaminoglycan chondroitin 4-sulfate as a heparin surrogate for pRBC targeting. The results presented indicate that the tuning of existing nanovessels to new malaria-related targets is a valid low-cost alternative to the de novo development of targeted nanosystems.

Keywords: Glycosaminoglycans, Malaria, Nanomedicine, Plasmodium, Targeted drug delivery


Aláez-Versón, C. R., Lantero, E., Fernàndez-Busquets, X., (2017). Heparin: New life for an old drug Nanomedicine 12, (14), 1727-1744

Heparin is one of the oldest drugs, which nevertheless remains in widespread clinical use as an inhibitor of blood coagulation. The history of its identification a century ago unfolded amid one of the most fascinating scientific controversies turning around the distribution of credit for its discovery. The composition, purification and structure-function relationship of this naturally occurring glycosaminoglycan regarding its classical role as anticoagulant will be dealt with before proceeding to discuss its therapeutic potential in, among other, inflammatory and infectious disease, cancer treatment, cystic fibrosis and Alzheimer's disease. The first bibliographic reference hit using the words 'nanomedicine' and 'heparin' is as recent as 2008. Since then, nanomedical applications of heparin have experienced an exponential growth that will be discussed in detail, with particular emphasis on its antimalarial activity. Some of the most intriguing potential applications of heparin nanomedicines will be exposed, such as those contemplating the delivery of drugs to the mosquito stages of malaria parasites.

Keywords: Anopheles, Antimalarial drugs, Heparin, Malaria, Mosquitoes, Nanomedicine, Nanotechnology, Plasmodium, Targeted drug delivery


Moles, E., Galiano, S., Gomes, A., Quiliano, M., Teixeira, C., Aldana, I., Gomes, P., Fernàndez-Busquets, X., (2017). ImmunoPEGliposomes for the targeted delivery of novel lipophilic drugs to red blood cells in a falciparum malaria murine model Biomaterials 145, 178-191

Most drugs currently entering the clinical pipeline for severe malaria therapeutics are of lipophilic nature, with a relatively poor solubility in plasma and large biodistribution volumes. Low amounts of these compounds do consequently accumulate in circulating Plasmodium-infected red blood cells, exhibiting limited antiparasitic activity. These drawbacks can in principle be satisfactorily dealt with by stably encapsulating drugs in targeted nanocarriers. Here this approach has been adapted for its use in immunocompetent mice infected by the Plasmodium yoelii 17XL lethal strain, selected as a model for human blood infections by Plasmodium falciparum. Using immunoliposomes targeted against a surface protein characteristic of the murine erythroid lineage, the protocol has been applied to two novel antimalarial lipophilic drug candidates, an aminoquinoline and an aminoalcohol. Large encapsulation yields of >90% were obtained using a citrate-buffered pH gradient method and the resulting immunoliposomes reached in vivo erythrocyte targeting and retention efficacies of >80%. In P. yoelii-infected mice, the immunoliposomized aminoquinoline succeeded in decreasing blood parasitemia from severe to uncomplicated malaria parasite densities (i.e. from ≥25% to ca. 5%), whereas the same amount of drug encapsulated in non-targeted liposomes had no significant effect on parasite growth. Pharmacokinetic analysis indicated that this good performance was obtained with a rapid clearance of immunoliposomes from the circulation (blood half-life of ca. 2 h), suggesting a potential for improvement of the proposed model.

Keywords: Immunoliposomes, Malaria, Nanomedicine, Plasmodium falciparum, Plasmodium yoelii 17XL, Targeted drug delivery


Moles, E., Moll, K., Ch'ng, J. H., Parini, P., Wahlgren, M., Fernàndez-Busquets, X., (2016). Development of drug-loaded immunoliposomes for the selective targeting and elimination of rosetting Plasmodium falciparum-infected red blood cells Journal of Controlled Release 241, 57-67

Parasite proteins exported to the surface of Plasmodium falciparum-parasitized red blood cells (pRBCs) have a major role in severe malaria clinical manifestation, where pRBC cytoadhesion and rosetting processes have been strongly linked with microvascular sequestration while avoiding both spleen filtration and immune surveillance. The parasite-derived and pRBC surface-exposed PfEMP1 protein has been identified as one of the responsible elements for rosetting and, therefore, considered as a promising vaccine candidate for the generation of rosette-disrupting antibodies against severe malaria. However, the potential role of anti-rosetting antibodies as targeting molecules for the functionalization of antimalarial drug-loaded nanovectors has never been studied. Our manuscript presents a proof-of-concept study where the activity of an immunoliposomal vehicle with a dual performance capable of specifically recognizing and disrupting rosettes while simultaneously eliminating those pRBCs forming them has been assayed in vitro. A polyclonal antibody against the NTS-DBL1

Keywords: Combination therapy, Immunoliposomes, Malaria, Nanomedicine, Rosetting, Targeted drug delivery


Fernàndez-Busquets, X., (2016). Novel strategies for Plasmodium-targeted drug delivery Expert Opinion on Drug Delivery 13, (7), 919-922

Moles, E., Urbán, P., Jiménez-Díaz, M. B., Viera-Morilla, S., Angulo-Barturen, I., Busquets, M. A., Fernàndez-Busquets, X., (2015). Immunoliposome-mediated drug delivery to Plasmodium-infected and non-infected red blood cells as a dual therapeutic/prophylactic antimalarial strategy Journal of Controlled Release 210, 217-229

One of the most important factors behind resistance evolution in malaria is the failure to deliver sufficiently high amounts of drugs to early stages of Plasmodium-infected red blood cells (pRBCs). Despite having been considered for decades as a promising approach, the delivery of antimalarials encapsulated in immunoliposomes targeted to pRBCs has not progressed towards clinical applications, whereas in vitro assays rarely reach drug efficacy improvements above 10-fold. Here we show that encapsulation efficiencies reaching >96% are achieved for the weak basic drugs chloroquine (CQ) and primaquine using the pH gradient loading method in liposomes containing neutral saturated phospholipids. Targeting antibodies are best conjugated through their primary amino groups, adjusting chemical crosslinker concentration to retain significant antigen recognition. Antigens from non-parasitized RBCs have also been considered as targets for the delivery to the cell of drugs not affecting the erythrocytic metabolism. Using this strategy, we have achieved unprecedented complete nanocarrier targeting to early intraerythrocytic stages of the malaria parasite for which there is a lack of specific extracellular molecular tags. Immunoliposomes studded with monoclonal antibodies raised against the erythrocyte surface protein glycophorin A were capable of targeting 100% RBCs and pRBCs at the low concentration of 0.5 μM total lipid in the culture, with >95% of added liposomes retained on cell surfaces. When exposed for only 15 min to Plasmodium falciparum in vitro cultures of early stages, free CQ had no significant effect on the viability of the parasite up to 200 nM, whereas immunoliposomal 50 nM CQ completely arrested its growth. In vivo assays in mice showed that immunoliposomes cleared the pathogen below detectable levels at a CQ dose of 0.5 mg/kg, whereas free CQ administered at 1.75 mg/kg was, at most, 40-fold less efficient. Our data suggest that this significant improvement is in part due to a prophylactic effect of CQ found by the pathogen in its host cell right at the very moment of invasion.

Keywords: Immunoliposomes, Malaria, Nanomedicine, Plasmodium, Targeted drug delivery


Moles, E., Fernàndez-Busquets, X., (2015). Loading antimalarial drugs into noninfected red blood cells: An undesirable roommate for Plasmodium Future Medicinal Chemistry 7, (7), 837-840

The malaria parasite, Plasmodium spp., is a delicate unicellular organism unable to survive in free form for more than a couple of minutes in the bloodstream. Upon injection in a human by its Anopheles mosquito vector, Plasmodium sporozoites pass through the liver with the aim of invading hepatocytes. Those which succeed spend inside their host cell a recovery time before replicating and entering the blood circulation as fragile merozoites, although their exposure to host defenses is extraordinarily short. Quick invasion of red blood cells (RBCs) in a process lasting just a few minutes allows the parasite to escape immune system surveillance. For most of its erythrocytic cycle the pathogen feeds mainly on hemoglobin as it progresses from the early blood stages, termed rings, to the late forms trophozoites and schizonts. Early stages are ideal targets for antimalarial therapies because drugs delivered to them would have a longer time to kill the parasite before it completes its development. However, only 6 h after invasion does the permeability of the infected erythrocyte to anions and small nonelectrolytes, including some drugs, start to increase as the parasite matures [1]. During this maturation process the parasite hydrolyzes hemoglobin in a digestive vacuole, which is the target of many amphiphilic drugs that freely cross the RBC membrane and accumulate intracellularly. As a result, most antimalarials start affecting the infected cell relatively late in the intraerythrocytic parasite life cycle, when their effect is probably often too short to be lethal to Plasmodium.

Keywords: Malaria, Nanomedicine, Plasmodium, Red blood cell, Targeted drug delivery


Fernàndez-Busquets, X., (2014). Toy kit against malaria: Magic bullets, LEGO, Trojan horses and Russian dolls Therapeutic Delivery 5, (10), 1049-1052

Movellan, J., Urbán, P., Moles, E., de la Fuente, J. M., Sierra, T., Serrano, J. L., Fernàndez-Busquets, X., (2014). Amphiphilic dendritic derivatives as nanocarriers for the targeted delivery of antimalarial drugs Biomaterials 35, (27), 7940-7950

It can be foreseen that in a future scenario of malaria eradication, a varied armamentarium will be required, including strategies for the targeted administration of antimalarial compounds. The development of nanovectors capable of encapsulating drugs and of delivering them to Plasmodium-infected cells with high specificity and efficacy and at an affordable cost is of particular interest. With this objective, dendritic derivatives based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) and Pluronic® polymers have been herein explored. Four different dendritic derivatives have been tested for their capacity to encapsulate the antimalarial drugs chloroquine (CQ) and primaquine (PQ), their specific targeting to Plasmodium-infected red blood cells (pRBCs), and their antimalarial activity invitro against the human pathogen Plasmodium falciparum and invivo against the rodent malaria species Plasmodium yoelii. The results obtained have allowed the identification of two dendritic derivatives exhibiting specific targeting to pRBCs vs. non-infected RBCs, which reduce the invitro IC50 of CQ and PQ by ca. 3- and 4-fold down to 4.0nm and 1.1μm, respectively. This work on the application of dendritic derivatives to antimalarial targeted drug delivery opens the way for the use of this new type of chemicals in future malaria eradication programs.

Keywords: Antimalarial targeted drug delivery, Dendrimers, Malaria, Nanomedicine, Plasmodium, Polymeric nanoparticles


Urbán, P., Valle-Delgado, J. J., Mauro, N., Marques, J., Manfredi, A., Rottmann, M., Ranucci, E., Ferruti, P., Fernàndez-Busquets, X., (2014). Use of poly(amidoamine) drug conjugates for the delivery of antimalarials to Journal of Controlled Release 177, (1), 84-95

Current malaria therapeutics demands strategies able to selectively deliver drugs to Plasmodium-infected red blood cells (pRBCs) in order to limit the appearance of parasite resistance. Here, the poly(amidoamines) AGMA1 and ISA23 have been explored for the delivery of antimalarial drugs to pRBCs. AGMA1 has antimalarial activity per se as shown by its inhibition of the in vitro growth of Plasmodium falciparum, with an IC50 of 13.7 μM. Fluorescence-assisted cell sorting data and confocal fluorescence microscopy and transmission electron microscopy images indicate that both polymers exhibit preferential binding to and internalization into pRBCs versus RBCs, and subcellular targeting to the parasite itself in widely diverging species such as P. falciparum and Plasmodium yoelii, infecting humans and mice, respectively. AGMA1 and ISA23 polymers with hydrodynamic radii around 7 nm show a high loading capacity for the antimalarial drugs primaquine and chloroquine, with the final conjugate containing from 14.2% to 32.9% (w/w) active principle. Intraperitoneal administration of 0.8 mg/kg chloroquine as either AGMA1 or ISA23 salts cured P. yoelii-infected mice, whereas control animals treated with twice as much free drug did not survive. These polymers combining into a single chemical structure drug carrying capacity, low unspecific toxicity, high biodegradability and selective internalization into pRBCs, but not in healthy erythrocytes for human and rodent malarias, may be regarded as promising candidates deserving to enter the antimalarial therapeutic arena.

Keywords: Malaria, Nanomedicine, Plasmodium, Polyamidoamines, Polymer-drug carriers, Targeted drug delivery


Marques, J., Moles, E., Urbán, P., Prohens, R., Busquets, M. A., Sevrin, C., Grandfils, C., Fernàndez-Busquets, X., (2014). Application of heparin as a dual agent with antimalarial and liposome targeting activities toward Plasmodium-infected red blood cells Nanomedicine: Nanotechnology, Biology, and Medicine 10, (8), 1719-1728

Heparin had been demonstrated to have antimalarial activity and specific binding affinity for Plasmodium-infected red blood cells (pRBCs) vs. non-infected erythrocytes. Here we have explored if both properties could be joined into a drug delivery strategy where heparin would have a dual role as antimalarial and as a targeting element of drug-loaded nanoparticles. Confocal fluorescence and transmission electron microscopy data show that after 30. min of being added to living pRBCs fluorescein-labeled heparin colocalizes with the intracellular parasites. Heparin electrostatically adsorbed onto positively charged liposomes containing the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane and loaded with the antimalarial drug primaquine was capable of increasing three-fold the activity of encapsulated drug in Plasmodium falciparum cultures. At concentrations below those inducing anticoagulation of mouse blood in vivo, parasiticidal activity was found to be the additive result of the separate activities of free heparin as antimalarial and of liposome-bound heparin as targeting element for encapsulated primaquine. From the Clinical Editor: Malaria remains an enormous global public health concern. In this study, a novel functionalized heparin formulation used as drug delivery agent for primaquine was demonstrated to result in threefold increased drug activity in cell cultures, and in a murine model it was able to provide these benefits in concentrations below what would be required for anticoagulation. Further studies are needed determine if this approach is applicable in the human disease as well.

Keywords: Heparin, Liposomes, Malaria, Plasmodium, Targeted drug delivery, Heparin, Malaria, Plasmodium, Red blood cell, Targeted drug delivery, Liposomes, 1,2 dioleoyl 3 trimethylammoniopropane, fluorescein, heparin, liposome, nanoparticle, primaquine, adsorption, animal experiment, anticoagulation, antimalarial activity, Article, binding affinity, confocal microscopy, controlled study, drug targeting, encapsulation, erythrocyte, female, fluorescence microscopy, human, human cell, in vivo study, liposomal delivery, mouse, nonhuman, Plasmodium falciparum, transmission electron microscopy


Urbán, P., Fernàndez-Busquets, X., (2014). Nanomedicine against malaria Current Medicinal Chemistry 21, (5), 605-629

Malaria is arguably one of the main medical concerns worldwide because of the numbers of people affected, the severity of the disease and the complexity of the life cycle of its causative agent, the protist Plasmodium sp. The clinical, social and economic burden of malaria has led for the last 100 years to several waves of serious efforts to reach its control and eventual eradication, without success to this day. With the advent of nanoscience, renewed hopes have appeared of finally obtaining the long sought-after magic bullet against malaria in the form of a nanovector for the targeted delivery of antimalarial drugs exclusively to Plasmodium-infected cells. Different types of encapsulating structure, targeting molecule, and antimalarial compound will be discussed for the assembly of Trojan horse nanocapsules capable of targeting with complete specificity diseased cells and of delivering inside them their antimalarial cargo with the objective of eliminating the parasite with a single dose. Nanotechnology can also be applied to the discovery of new antimalarials through single-molecule manipulation approaches for the identification of novel drugs targeting essential molecular components of the parasite. Finally, methods for the diagnosis of malaria can benefit from nanotools applied to the design of microfluidic-based devices for the accurate identification of the parasite's strain, its precise infective load, and the relative content of the different stages of its life cycle, whose knowledge is essential for the administration of adequate therapies. The benefits and drawbacks of these nanosystems will be considered in different possible scenarios, including cost-related issues that might be hampering the development of nanotechnology-based medicines against malaria with the dubious argument that they are too expensive to be used in developing areas.

Keywords: Dendrimers, Liposomes, Malaria diagnosis, Nanobiosensors, Nanoparticles, Plasmodium, Polymers, Targeted drug delivery


Fernàndez-Busquets, X., (2013). Amyloid fibrils in neurodegenerative diseases: villains or heroes? Future Medicinal Chemistry 5, (16), 1903-1906

Fernàndez-Busquets, X., (2013). Heparin-functionalized nanocapsules: Enabling targeted delivery of antimalarial drugs Future Medicinal Chemistry 5, (7), 737-739

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