Development of 4-sulfated N-acetyl galactosamine anchored chitosan nanoparticles: A dual strategy for effective management of Leishmaniasis

Spleen-targeted delivery systems and strategies for spleen-related diseases

The spleen, body's largest secondary lymphoid organ, is also a vital hematopoietic and immunological organ. It is regarded as one of the most significant organs in humans. As more researchers recognize the functions of the spleen, clinical methods for treating splenic diseases and spleen-targeted drug delivery systems to improve the efficacy of spleen-related therapies have gradually developed. Many modification strategies (size, charge, ligand, protein corona) and hitchhiking strategies (erythrocytes, neutrophils) of nanoparticles (NPs) have shown a significant increase in spleen targeting efficiency. However, most of the targeted drug therapy strategies for the spleen are to enhance or inhibit the immune function of the spleen to achieve therapeutic effects, and there are few studies on spleen-related diseases. In this review, we not only provide a detailed summary of the design rules for spleen-targeted drug delivery systems in recent years, but also introduce common spleen diseases (splenic tumors, splenic injuries, and splenomegaly) with the hopes of generating more ideas for future spleen research.

Developing nanosize carrier systems for Amphotericin-B: A review on the biomedical application of nanoparticles for the treatment of leishmaniasis and fungal infections

New formulations of Amphotericin-B (Am-B), the most popular therapeutic drug for many human infections such as parasitic and fungal pathogens, are safe, economical, and effective in the world. Several newly designed carrier systems for Am-B can also be considered orally with sufficient gastrointestinal permeability and good solubility. However, the clinical application of several new formulations of Am-B with organ cytotoxicity, low bioavailability, high costs, and technical problems have caused some issues. Therefore, more attention and scientific design are required to progress safe and effective drug delivery systems. Currently, the application of nano-based technology and nanomaterials in the advancement of drug delivery systems exhibits promising outcomes to cure many human systemic infections. Designing novel drug delivery systems including solid lipid nanostructured materials, lipo-polymersomes, drug conjugates and microneedles, liposomes, polymer and protein-based nanostructured materials, dendrimers, emulsions, mixed micelles, polymeric micelles, cyclodextrins, nanocapsules, and nanocochleate for Am-B has many advantages to reducing several related issues. The unique properties of nanostructured particles such as proper morphology, small size, surface coatings, and, electrical charge, permit scientists to design new nanocomposite materials against microorganisms for application in various human diseases. These features have made these nanoparticles an ideal candidate for drug delivery systems in clinical approaches to cure a number of human disorders and currently, several therapeutic nanostructured material formulations are under different stages of clinical tests. Hence, this scientific paper mainly discussed the advances in new formulations of Am-B for the treatment of human systemic infections and related clinical tests.

Development of Spleen Targeting H2S Donor Loaded Liposome for the Effective Systemic Immunomodulation and Treatment of Inflammatory Bowel Disease

Nanoparticles are primarily taken up by immune cells after systemic administration. Thus, they are considered an ideal drug delivery vehicle for immunomodulation. Because the spleen is the largest lymphatic organ and regulates the systemic immune system, there have been studies to develop spleen targeting nanoparticles for immunomodulation of cancer and immunological disorders. Inflammatory bowel disease (IBD) includes disorders involving chronic inflammation in the gastrointestinal tract and is considered incurable despite a variety of treatment options. Hydrogen sulfide (H₂S) is one of the gasotransmitters that carries out anti-inflammatory functions and has shown promising immunomodulatory effects in various inflammatory diseases including IBD. Herein, we developed a delicately tuned H₂S donor delivering liposome for spleen targeting (ST-H₂S lipo) and studied its therapeutic effects in a dextran sulfate sodium (DSS) induced colitis model. We identified the ideal PEG type and ratio of liposome for a high stability, loading efficiency, and spleen targeting effect. In the treatment of the DSS-induced colitis model, we found that ST-H₂S lipo and conventional long-circulating liposomes loaded with H₂S donors (LC-H₂S lipo) reduced the severity of colitis, whereas unloaded H₂S donors did not. Furthermore, the therapeutic effect of ST-H₂S lipo was superior to that of LC-H₂S lipo due to its better systemic immunomodulatory effect than that of LC-H₂S lipo. Our findings demonstrate that spleen targeting H₂S lipo may have therapeutic potential for IBD.

The Designing of a Gel Formulation with Chitosan Polymer Using Liposomes as Nanocarriers of Amphotericin B for a Non-invasive Treatment Model of Cutaneous Leishmaniasis

PURPOSE

Leishmaniasis is a disease caused by different Leishmania spp., which are transmitted to humans by a bite of infected female sand flies. Cutaneous leishmaniasis (CL, oriental sore), visceral leishmaniasis (VL), and mucocutaneous leishmaniasis (MCL) are three main clinical forms, however, only CL and VL are seen in Turkey. Cutaneous leishmaniasis is characterized by skin lesion(s) and is one of the most important vector-borne diseases in Turkey with over 2000 cases reported annually in 40 out of 81 provinces. The treatment is usually made invasively and painfully by intralesional injection of pentavalent antimony compounds. Non-invasive and innovative treatment methods are needed as aimed in this study.

METHODS

In the present study, one of the classical antileishmanial drugs, amphotericin B (AmB), encapsulated in liposomes was evaluated using non-invasive design based on chitosan, which is a nontoxic, biocompatible and biodegradable polymer. To avoid the invasive effect of conventional intralesional needle application, the drug was encapsulated in liposomes and incorporated into a chitosan gel for applying topically on the skin lesion. The efficacy of encapsulation of amphotericin B into liposomes and the drug release from liposomes were studied. The chitosan gel was evaluated for viscosity, flowability, appearance and pH. The efficacy of the drug embedded into chitosan gel, liposomal AmB alone and chitosan gel alone in four different concentrations was also tested using Leishmania spp. promastigotes in vitro.

RESULTS

The findings have shown that AmB was encapsulated into the liposomes with high efficiency (86.6%) and long-term physical and chemical stability. Therefore, designed liposomal formulation was suitable for sustained release. The appearance of the drug-embedded chitosan gel was transparent and appropriate. Chitosan gels showed non- Newtonian behavior and plastic flow. The liposomal AmB also showed higher efficacy with no parasites in all concentrations while drug embedded into chitosan gel and chitosan gel alone were effective in two higher concentrations. The lower efficacy of the drug-embedded chitosan gel in 24 h in in-vitro study was probably due to slow release of the drug.

CONCLUSION

The gel design created in this study will provide ease of use for the lesions of CL patients that do not have a specific number, size, and shape. Follow-up studies by the ex-vivo macrophage infection model with Leishmania intracellular amastigote forms and Leishmania-infected animal models are needed to understand the present design's efficacy better.

Nanotechnology-aided diagnosis, treatment and prevention of leishmaniasis

Leishmaniasis is a prevalent parasitic infection belonging to neglected tropical diseases. It is caused by Leishmania protozoan parasites transmitted by sandflies and it is responsible for increased morbidity/mortality especially in low- and middle-income countries. The lack of cheap, portable, easy to use diagnostic tools exhibiting high efficiency and specificity impede the early diagnosis of the disease. Furthermore, the typical anti-leishmanial agents are cytotoxic, characterized by low patient compliance and require long-term regimen and usually hospitalization. In addition, due to the intracellular nature of the disease, the existing treatments exhibit low bioavailability resulting in low therapeutic efficacy. The above, combined with the common development of resistance against the anti-leishmanial agents, denote the urgent need for novel therapeutic strategies. Furthermore, the lack of effective prophylactic vaccines hinders the control of the disease. The development of nanoparticle-based biosensors and nanocarrier-aided treatment and vaccination strategies could advance the diagnosis, therapy and prevention of leishmaniasis. The present review intends to highlight the various nanotechnology-based approaches pursued until now to improve the detection of Leishmania species in biological samples, decrease the side effects and increase the efficacy of anti-leishmanial drugs, and induce enhanced immune responses, specifically focusing on the outcome of their preclinical and clinical evaluation.

A Combined Antitumor Strategy Mediated by a New Targeted Nanosystem to Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the main causes of cancer-related death. Sorafenib, which is the first-line therapy for this disease, is associated with reduced therapeutic efficacy that could potentially be overcome by combination with selumetinib. In this context, the main goal of this work was to develop a new nanosystem, composed of a polymeric core coated by a lipid bilayer containing the targeting ligand GalNAc, to specifically and efficiently co-deliver both drugs into HCC cells, in order to significantly increase their therapeutic efficacy.

METHODS

The physicochemical characterization of hybrid nanosystems (HNP) and their components was performed by dynamic light scattering, zeta potential, matrix-assisted laser desorption ionization - time of flight mass spectroscopy, and transmission electron microscopy. Cellular binding, uptake and specificity of HNP were evaluated through flow cytometry and confocal microscopy. The therapeutic activity was evaluated namely through: cell viability by the Alamar Blue assay; cell death by flow cytometry using FITC-Annexin V; caspases activity by luminescence; mitochondrial membrane potential by flow cytometry; and molecular target levels by Western blot.

RESULTS

The obtained data show that these hybrid nanosystems present high stability and loading capacity of both drugs, and suitable physicochemical properties, namely in terms of size and surface charge. Moreover, the generated formulation allows to circumvent drug resistance and presents high specificity, promoting great cell death levels in HCC cells, but not in non-tumor cells. This potentiation of the antitumor effect of co-loaded drugs was carried out by an increased programmed cell death, being associated with a strong reduction in the mitochondrial membrane potential, a significant increase in the activity of caspases 3/7 and caspase 9, and much greater number of annexin V-positive cells.

CONCLUSION

The developed formulation resulted in a high and synergistic antitumor effect, revealing a translational potential to improve therapeutic approaches against HCC.

Nanotechnology approaches for delivery and targeting of Amphotericin B in fungal and parasitic diseases

Amphotericin B (AMB), with widespread antifungal and anti-parasitic activities and low cross-resistance with other drugs, has long been identified as a potent antimicrobial drug. However, its clinical toxicities, especially nephrotoxicity, have limited its use in clinical practice. Lately, nano-based systems have been the subject of serious research and becoming an effective strategy to improve toxicity and antimicrobial potency. Commercial AMB lipid formulations have been developed in order to improve the therapeutic index and nephrotoxicity, while limited use is mainly due to their high cost. The review aimed to highlight the updated information on nanotechnology-based approaches to the development of AMB delivery and targeting systems for treatment of fungal diseases and leishmaniasis, regarding therapeutic challenges and achievements of various delivery systems.

Albalawi A, Alanazi AD, Baharvand P, Moghaddam A, Mahmoudvand H. Chitosan-Based Nanomaterials as Valuable Sources of Anti-Leishmanial Agents: A Systematic Review

BACKGROUND

The current chemotherapy agents against various forms of leishmaniasis have some problems and side effects, including high toxicity, high cost, and the emergence of resistant strains. Here, we aimed to review the preclinical studies (in vitro and in vivo) on the anti-leishmanial activity of chitosan and chitosan-based particles against Leishmania spp.

METHODS

This study was conducted based on the 06-PRISMA guidelines and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-Analysis Facility (SyRF) database. Various English databases such as PubMed, Google Scholar, Web of Science, EBSCO, ScienceDirect, and Scopus were used to find the publications related to the anti-leishmanial effects of chitosan and its derivatives and other pharmaceutical formulations, without a date limitation, to find all the published articles. The keywords included "chitosan", "chitosan nanoparticles", "anti-leishmanial", "Leishmania", "leishmaniasis", "cutaneous leishmaniasis", "visceral leishmaniasis", "in vitro", and "in vivo". The language for data collection were limited to English.

RESULTS

Of 2669 papers, 25 papers, including 7 in vitro (28.0%), 7 in vivo (28.0%), and 11 in vitro/in vivo (44.0%) studies conducted up to 2020 met the inclusion criteria for discussion in this systematic review. The most common species of Leishmania used in these studies were L. major (12, 48.0%), L. donovani (7, 28.0%), and L. amazonensis (4, 16.80%). In vivo, the most used animals were BALB/c mice (11, 61.1%) followed by hamsters (6, 33.3%) and Wistar rats (1, 5.5%), respectively. In vitro, the most used Leishmania form was amastigote (8, 44.4%), followed by promastigote (4, 22.2%), and both forms promastigote/amastigote (6, 33.3%).

CONCLUSION

According to the literature, different types of drugs based on chitosan and their derivatives demonstrated considerable in vitro and in vivo anti-leishmanial activity against various Leishmania spp. Based on the findings of this review study, chitosan and its derivatives could be considered as an alternative and complementary source of valuable components against leishmaniasis with a high safety index. Nevertheless, more investigations are required to elaborate on this result, mainly in clinical settings.

Chitosan Contribution to Therapeutic and Vaccinal Approaches for the Control of Leishmaniasis

The control of leishmaniases, a complex parasitic disease caused by the protozoan parasite Leishmania, requires continuous innovation at the therapeutic and vaccination levels. Chitosan is a biocompatible polymer administrable via different routes and possessing numerous qualities to be used in the antileishmanial strategies. This review presents recent progress in chitosan research for antileishmanial applications. First data on the mechanism of action of chitosan revealed an optimal in vitro intrinsic activity at acidic pH, high-molecular-weight chitosan being the most efficient form, with an uptake by pinocytosis and an accumulation in the parasitophorous vacuole of Leishmania-infected macrophages. In addition, the immunomodulatory effect of chitosan is an added value both for the treatment of leishmaniasis and the development of innovative vaccines. The advances in chitosan chemistry allows pharmacomodulation on amine groups opening various opportunities for new polymers of different size, and physico-chemical properties adapted to the chosen routes of administration. Different formulations have been studied in experimental leishmaniasis models to cure visceral and cutaneous leishmaniasis, and chitosan can act as a booster through drug combinations with classical drugs, such as amphotericin B. The various architectural possibilities given by chitosan chemistry and pharmaceutical technology pave the way for promising further developments.

Chitosan-based particulate systems for drug and vaccine delivery in the treatment and prevention of neglected tropical diseases

Neglected tropical diseases (NTDs) are a diverse group of infections which are difficult to prevent or control, affecting impoverished communities that are unique to tropical or subtropical regions. In spite of the low number of drugs that are currently used for the treatment of these diseases, progress on new drug discovery and development for NTDs is still very limited. Therefore, strategies on the development of new delivery systems for current drugs have been the main focus of formulators to provide improved efficacy and safety. In recent years, particulate delivery systems at micro- and nanosize, including polymeric micro- and nanoparticles, liposomes, solid lipid nanoparticles, metallic nanoparticles, and nanoemulsions, have been widely investigated in the treatment and control of NTDs. Among these polymers used for the preparation of such systems is chitosan, which is a marine biopolymer obtained from the shells of crustaceans. Chitosan has been investigated as a delivery system due to the versatility of its physicochemical properties as well as bioadhesive and penetration-enhancing properties. Furthermore, chitosan can be also used to improve treatment due to its bioactive properties such as antimicrobial, tissue regeneration, etc. In this review, after giving a brief introduction to neglected diseases and particulate systems developed for the treatment and control of NTDs, the chitosan-based systems will be described in more detail and the recent studies on these systems will be reviewed. Graphical abstract.

Carbohydrate-based nanocarriers and their application to target macrophages and deliver antimicrobial agents

Many deadly infections are produced by microorganisms capable of sustained survival in macrophages. This reduces exposure to chemadrotherapy, prevents immune detection, and is akin to criminals hiding in police stations. Therefore, the use of glyco-nanoparticles (GNPs) as carriers of therapeutic agents is a burgeoning field. Such an approach can enhance the penetration of drugs into macrophages with specific carbohydrate targeting molecules on the nanocarrier to interact with macrophage lectins. Carbohydrates are natural biological molecules and the key constituents in a large variety of biological events such as cellular communication, infection, inflammation, enzyme trafficking, cellular migration, cancer metastasis and immune functions. The prominent characteristics of carbohydrates including biodegradability, biocompatibility, hydrophilicity and the highly specific interaction of targeting cell-surface receptors support their potential application to drug delivery systems (DDS). This review presents the 21^st century development of carbohydrate-based nanocarriers for drug targeting of therapeutic agents for diseases localized in macrophages. The significance of natural carbohydrate-derived nanoparticles (GNPs) as anti-microbial drug carriers is highlighted in several areas of treatment including tuberculosis, salmonellosis, leishmaniasis, candidiasis, and HIV/AIDS.

Comparative analysis between four model nanoformulations of amphotericin B-chitosan, amphotericin B-dendrimer, betulinic acid-chitosan and betulinic acid-dendrimer for treatment of Leishmania major: real-time PCR assay plus

Background

Amphotericin B (Amp) and Betulinic acid (BA) as antileishmanial agents have negligible water solubility and high toxicity. To solve these problems, for the first time, chitosan nanoparticles and Anionic Linear Globular Dendrimer (D) were synthesized for the treatment of Leishmania major (L. major).

Method

Chitosan and dendrimer nanoparticles were synthesized, and Amp and BA were loaded into the nanoparticles. The particles were then characterized using various methods and their efficacy was evaluated in vitro and in vivo environments (parasite burden was confirmed using pathological studies and real-time PCR methods).

Result

The results of docking showed that Amp and BA can be loaded into chitosan and dendrimer nanoparticles. The results of physically drug loading efficiency for AK (Amphotericin B-chitosan), BK (Betulinic acid-chitosan), AD (Amphotericin B-Dendrimer) and BD (Betulinic acid- Dendrimer) were 90, 93, 84 and 96 percent, respectively. The characterization results indicated that the drugs were loaded into nanoparticles physically. Moreover, the increased solubility rate for AD=478, BD=790, AK=80 and BK=300 folds. Furthermore, the results of the drug delivery system showed the slow controlled drug release pattern with cellular uptake of more than 90%. The treatment results showed a 100 percent decrease of toxicity for the all nanodrugs was observed in vivo and in vitro environments. Moreover, AK10 and BK20 mg/kg reduced parasite burden by 83 percent (P<0.001), while AD50 and BD40 mg/kg reduced it to a lesser extent compared to glucantime.

Conclusion

All the synthesized nanodrugs were completely succeeded by 100% to recovery the L. major induced pathological effects in the infected footpad. Also, the results of present study were confirmed with real-time PCR and the results showed that AK and BK were succeeded in a large extent to the treatment of L. major infection (P<0.001), therefore AK and BK could be considered as proper alternatives of choices drugs.

Novel nano-sized chitosan amphotericin B formulation with considerable improvement against Leishmania major

AIM

Improvement in the treatment of Leishmania major's pathological effects through increasing the dose of amphotericin B loaded into nanochitosan.

MATERIALS & METHODS

The phase separation method was used for nanochitosan synthesis and amphotericin loading. Also a novel solvent was designed and the nanodrug efficacy was evaluated in vitro and in vivo (pathology) environments.

RESULTS

The drug loading efficiency of 90%, along with slow drug-release with cellular uptake of 98.6% was achieved. The novel solvent was composed of 10% acetic acid, and it was succeeded to dissolve AK10 mg/kg. Also, AK10 mg/kg had no side effects in in vitro and in vivo environments. In addition, the complete wound healing and parasite inhibition were achieved by using AK10 mg/kg in terms of improvement the treatment indicators.

CONCLUSION

Increasing the therapeutic dose of AK to 10 mg/kg caused the successful treatment of L. major's pathological effects in in vitro and in vivo environments.

Carbomer gel bearing methotrexate loaded lipid nanocontainers shows improved topical delivery intended for effective management of psoriasis

The present investigation reports the evaluation of potential use of Carbomer gel bearing methotrexate loaded nanostructured lipid carriers for topical application of methotrexate for possible therapy of psoriasis in comparison to solid lipid nanoparticles. These were evaluated for various parameters such as particle size, surface charge, entrapment efficiency, shape and surface morphology, thermal analysis, in-vitro drug release through skin (Franz diffusion cell) and drug deposition study, fluorescence microscopy, particle-skin interaction study, skin-irritation testing and storage stability. The formulation (NLC₅) showed the best entrapment efficiency (62.72 ± 0.94%) while SLN showed only 26.84 ± 0.64% with particle size of 221 ± 14nm and 212 ± 11nm, respectively. Skin permeation study of MTX loaded SLN and NLC₅ hydrogels showed prolonged drug release up to 24 h. The skin drug deposition study showed the greatest deposition of drug enriched NLC₅ hydrogel (28.8%) when compared to plain drug enriched hydrogel (11.4%) and drug enriched SLN hydrogel (18.6%). Fluorescence microscopy suggested the localization effect of these lipid based systems to deeper skin region. The primary skin irritation studies indicated that MTX loaded SLN or NLC₅ hydrogels resulted no erythema. It can be concluded that NLC represents a promising particulate carrier having prolonged drug release, improved skin permeation.

Novel Nanosized Chitosan-Betulinic Acid Against Resistant Leishmania Major and First Clinical Observation of such parasite in Kidney

Regarding the antiparasitic effects of Betulinic acid (B) against Leishmaniasis, it was loaded into nanochitosan (K) for the first time in order to improve its therapeutic effects and decrease its side effects for the treatment of Leishmania major-infected Balb/c mice. Improvement the therapeutic efficacy of Bas an anti-leishmania agent through increasing the effective dose was achieved by using a novel solvent and phase separation method for K synthesis. The synthesized K with the size of 102 nm and Betulinic acid-nanochitosan (BK) with the size of 124 nm and drug loading efficiency of 93%, cellular uptake of 97.5% with the slow drug release pattern was prepared. To increase the therapeutic dose, a modified 10% acetic acid solvent was used. The in vitro and in vivo results showed that the nanodrug of BK was non toxic by 100% and BK20 mg/kg could completely performed the wound healing and inhibit the parasite in a large extent (P ˂ 0.001) compared to other groups. Therefore, BK could be considered as an alternative regimen for treatment of L. major.

Reduction toxicity of Amphotericin B through loading into a novel nanoformulation of anionic linear globular dendrimer for improve treatment of leishmania major

Amphotericin B (A) as an antileishmanial drug has limited clinical application owing to severe side-effects and low-water solubility. This is the first study reported using Anionic Linear Globular Dendrimer (ALGD) as A carrier for the increase of A solubility rate, decrease its toxicity, and improve its therapeutic effects. ALGD was synthesized and A was loaded into nanoparticles for the first time with the drug-loading efficiency of 82%. Drug loading was confirmed using characterization methods. The drug solubility rate was increased by 478-folds. The results of the study showed that the A toxicity was significantly decreased by 95% in vitro and in vivo environments, which was confirmed by pathology findings and enzymatic evaluation. Furthermore, the nanodrug caused that mortality rate was reached to zero. Moreover, the nanodrug was as potent as the free drug and glucantime (GUL) in reducing the parasite burden and parasite number. These findings indicated the potency of ALGD to decrease the drug side-effects, increase the drug solubility rate, and improve the drug efficacy. Moreover, the nanoformulation was a non-toxic and cost-effective formulation. The conformity between in vitro and in vivo results suggested that the A-loaded ALGD could be considered as a promising candidate in reducing the side-effects of A in leishmaniasis treatment.

Bovine serum albumin nanoparticles containing amphotericin B were effective in treating murine cutaneous leishmaniasis and reduced the drug toxicity

Cutaneous leishmaniasis is the most common form of leishmaniasis and the available chemotherapy causes serious side effects, justifying the search for new therapies. This study investigated the antileishmanial activity of bovine serum albumin (BSA) nanoparticles containing amphotericin B (AmB) against Leishmania amazonensis. The antiproliferative activity against promastigotes and amastigotes was assessed and the cytotoxicity was determined and compared to commercial AmB-deoxycholate (AmB-D). In vivo antileishmania activity was evaluated in murine cutaneous leishmaniasis model. BSA nanoparticles showed spherical shape, mean size about 180 nm, zeta potential of ≈ -45 mV and AmB encapsulation efficiency >95%. AmB-D was effective in promastigote and amastigote forms, while AmB-loaded BSA nanoparticles were more effective against amastigotes than promastigotes. AmB-D was more effective than AmB-loaded BSA nanoparticles in both forms, however, the lowest cytotoxicity against macrophages was achieved by AmB-nanoparticles. BALB/c mice treated with AmB-D or AmB-loaded BSA nanoparticles showed a significant decrease in the lesion thickness at the infected footpad. Histopathological analysis after 3 weeks of treatment revealed AmB-D-related toxicity in heart, spleen, lung, liver and kidneys, while treatment with AmB-loaded BSA nanoparticles did not reveal tissue toxicity. The antileishmanial efficacy and the reduced toxicity become BSA nanoparticles containing AmB a potential candidate for treating cutaneous leishmaniasis.

Nanocarriers for spleen targeting: anatomo-physiological considerations, formulation strategies and therapeutic potential

There are several clinical advantages of spleen targeting of nanocarriers. For example, enhanced splenic concentration of active agents could provide therapeutic benefits in spleen resident infections and hematological disorders including malaria, hairy cell leukemia, idiopathic thrombocytopenic purpura, and autoimmune hemolytic anemia. Furthermore, spleen delivery of immunosuppressant agents using splenotropic carriers may reduce the chances of allograft rejection in organ transplantation. Enhanced concentration of radiopharmaceuticals in the spleen may improve visualization of the organ, which could provide benefit in the diagnosis of splenic disorders. Unique anatomical features of the spleen including specialized microvasculature environment and slow blood circulation rate enable it an ideal drug delivery site. Because there is a difference in blood flow between spleen and liver, splenic delivery is inversely proportional to the hepatic uptake. It is therefore desirable engineering of nanocarriers, which, upon intravenous administration, can avoid uptake by hepatic Kupffer cells to enhance splenic localization. Stealth and non-spherical nanocarriers have shown enhanced splenic delivery of active agents by avoiding hepatic uptake. The present review details the research in the field of splenotropy. Formulation strategies to design splenotropic drug delivery systems are discussed. The review also highlights the clinical relevance of spleen targeting of nanocarriers and application in diagnostics.

Oral delivery of ursolic acid-loaded nanostructured lipid carrier coated with chitosan oligosaccharides: Development, characterization, in vitro and in vivo assessment for the therapy of leishmaniasis

Visceral leishmaniasis (VL) is a life-threatening disease caused by Leishmania donovani due to uncontrolled parasitisation of liver, spleen, and bone marrow. Ursolic acid (UA), a promising anti-inflammatory, anti-bacterial and anti-diabetic drug used successfully for treatment of ailments. Development of new delivery system is extremely urgent for UA with better efficacy and fewer side effects. The aim of present research work was to formulate and evaluate the potential anti-leishmanial activity of UA loaded N-octyl-chitosan surface decorated nanostructured lipid carrier system (UA-NLC) for delivery to the macrophages for VL. UA-NLC were prepared and characterized for shape, size, fourier transforms scanning electron microscopy (FESEM), transmittance electron microscopy (TEM), entrapment efficiency and in vitro drug release. The results indicate that the formulated UA-NLC had nano size range (103.7±2.8nm to 143.0±3.8nm) with high drug loading capacity (12.05±0.54%) and entrapment efficiency (88.63±2.7%). Ex vivo drug uptake by macrophage was also evaluated. The UA-NLC was more effective against AG83 wild type (12 fold), SSG-R (4 fold), PMM-R (4 fold) and GE1 field isolated (3 fold) cellular amastigotes than its free form. In vivo study showed orally effective UA-NLC could suppress the parasite burden to 98.75%.

Hexadecylphosphocholine (Miltefosine) stabilized chitosan modified Ampholipospheres as prototype co-delivery vehicle for enhanced killing of L. donovani

Lipid nanoparticles are stable, biodegradable and biocompatible carriers offering excellent therapeutic efficacy. Here, a novel effort has been made to develop Miltefosine (HePC- hexadecylphosphocholine) stabilized chitosan anchored nanostructured lipid carriers (NLC) of Amphotericin B (AmB) as co-delivery vehicle to enhance killing of L. donovani. The entrapment efficiency of AmB was achieved upto 85.3% for HePC-AmB-CNLCs with mean particle size of 150.8±8.4nm, and zeta potential value of +28.2±1.1mV, respectively. The cumulative amount of AmB released at even after the 24h was less than 65% from HePC-AmB-CNLCs and Tween-80-AmB-CNLCs. Intravenous administration of HePC-AmB-CNLCs revealed the significantly increased localization of AmB in both liver and spleen when estimated. FACS study represented enhanced uptake of FITC-HePC-CNLCs over FITC-HePC-NLCs in J774A.1 cell lines. Highly significant in vitro and in vivo anti-leishmanial activity (p<0.05 compared with Tween 80-AmB-CNLCs) was observed with HePC-AmB-CNLCs when tested against VL in Leishmania donovani-infected hamsters. The haemolysis and cytotoxicity studies showed the safety of HePC-AmB-CNLCs and Tween 80-AmB-CNLCs. The findings suggested that it would be preferable to deliver AmB through HePC stabilized chitosan anchored nanostructured lipid carriers for rapid and effective treatment with decreased adverse effects.