Antileishmanial Activity of Amphotericin B-loaded-PLGA Nanoparticles: An Overview

Revolutionizing Stroke Care: Nanotechnology-Based Brain Delivery as a Novel Paradigm for Treatment and Diagnosis

Stroke, a severe medical condition arising from abnormalities in the coagulation-fibrinolysis cycle and metabolic processes, results in brain cell impairment and injury due to blood flow obstruction within the brain. Prompt and efficient therapeutic approaches are imperative to control and preserve brain functions. Conventional stroke medications, including fibrinolytic agents, play a crucial role in facilitating reperfusion to the ischemic brain. However, their clinical efficacy is hampered by short plasma half-lives, limited brain tissue distribution attributed to the blood-brain barrier (BBB), and lack of targeted drug delivery to the ischemic region. To address these challenges, diverse nanomedicine strategies, such as vesicular systems, polymeric nanoparticles, dendrimers, exosomes, inorganic nanoparticles, and biomimetic nanoparticles, have emerged. These platforms enhance drug pharmacokinetics by facilitating targeted drug accumulation at the ischemic site. By leveraging nanocarriers, engineered drug delivery systems hold the potential to overcome challenges associated with conventional stroke medications. This comprehensive review explores the pathophysiological mechanism underlying stroke and BBB disruption in stroke. Additionally, this review investigates the utilization of nanocarriers for current therapeutic and diagnostic interventions in stroke management. By addressing these aspects, the review aims to provide insight into potential strategies for improving stroke treatment and diagnosis through a nanomedicine approach.

Green nanotech paradigm for enhancing sesquiterpene lactone therapeutics in cancer

In the field of cancer therapy, sesquiterpene lactones (SLs) derived from diverse Dicoma species demonstrate noteworthy bioactivity. However, the translation of their full therapeutic potential into clinical applications encounters significant challenges, primarily related to solubility, bioavailability, and precise drug targeting. Despite these obstacles, our comprehensive review introduces an innovative paradigm shift that integrates the inherent therapeutic properties of SLs with the principles of green nanotechnology. To overcome issues of solubility, bioavailability, and targeted drug delivery, eco-friendly strategies are proposed for synthesizing nanocarriers. Green nanotechnology has emerged as a focal point in addressing environmental and health concerns linked to conventional treatments. This progressive approach of green nanotechnology holds promise for the development of safe and sustainable nanomaterials, particularly in the field of drug delivery. This groundbreaking methodology signifies a pioneering advancement in the creation of novel and effective anticancer therapeutics. It holds substantial potential for transforming cancer treatment and advancing the landscape of natural product research.

Nano and microparticle drug delivery systems for the treatment of Brucella infections

Nano-based drug delivery systems are increasingly used for diagnosis, prevention and treatment of several diseases, thanks to several beneficial properties, including the ability to target specific cells or organs, allowing to reduce treatment costs and side effects frequently associated with chemotherapeutic medications, thereby improving treatment compliance of patients. In the field of communicable diseases, especially those caused by intracellular bacteria, the delivery of antibiotics targeting specific cells is of critical importance to maximize their treatment efficacy. Brucella melitensis, an intracellular obligate bacterium surviving and replicating inside macrophages is hard to be eradicated, mainly because of the low ability of antibiotics to enter these phagocityc cells . Although different antibiotics regimens including gentamicin, doxycycline and rifampicin are in fact used against the Brucellosis, no efficient treatment has been attained yet, due to the intracellular life of the respective pathogen. Nano-medicines responding to environmental stimuli allow to maximize drug delivery targeting macropages, thereby boosting treatment efficacy. Several drug delivery nano-technologies, including solid lipid nanoparticles, liposomes, chitosan, niosomes, and their combinations with chitosan sodium alginate can be employed in combination of antibiotics to successfully eradicate Brucellosis infection from patients.

A Systematic Review of Drug-Carrying Nanosystems Used in the Treatment of Leishmaniasis

Leishmaniasis is an infectious disease responsible for a huge rate of morbidity and mortality in humans. Chemotherapy consists of the use of pentavalent antimonial, amphotericin B, pentamidine, miltefosine, and paromomycin. However, these drugs are associated with some drawbacks such as high toxicity, administration by parenteral route, and most seriously the resistance of some strains of the parasite to them. Several strategies have been used to increase the therapeutic index and reduce the toxic effects of these drugs. Among them, the use of nanosystems that have great potential as a site-specific drug delivery system stands out. This review aims to compile results from studies that were carried out using first- and second-line antileishmanial drug-carrying nanosystems. The articles referred to here were published between 2011 and 2021. This study shows the promise of effective applicability of drug-carrying nanosystems in the field of antileishmanial therapeutics, with the perspective of providing better patient adherence to treatment, increased therapeutic efficacy, reduced toxicity of conventional drugs, as well as the potential to efficiently improve the treatment of leishmaniasis.

Targeting of phagolysosomes containing conidia of the fungus Aspergillus fumigatus with polymeric particles

Conidia of the airborne human-pathogenic fungus Aspergillus fumigatus are inhaled by humans. In the lung, they are phagocytosed by alveolar macrophages and intracellularly processed. In macrophages, however, conidia can interfere with the maturation of phagolysosomes to avoid their elimination. To investigate whether polymeric particles (PPs) can reach this intracellular pathogen in macrophages, we formulated dye-labeled PPs with a size allowing for their phagocytosis. PPs were efficiently taken up by RAW 264.7 macrophages and were found in phagolysosomes. When macrophages were infected with conidia prior to the addition of PPs, we found that they co-localized in the same phagolysosomes. Mechanistically, the fusion of phagolysosomes containing PPs with phagolysosomes containing conidia was observed. Increasing concentrations of PPs increased fusion events, resulting in 14% of phagolysosomes containing both conidia and PPs. We demonstrate that PPs can reach conidia-containing phagolysosomes, making these particles a promising carrier system for antimicrobial drugs to target intracellular pathogens. KEY POINTS: • Polymer particles of a size larger than 500 nm are internalized by macrophages and localized in phagolysosomes. • These particles can be delivered to Aspergillus fumigatus conidia-containing phagolysosomes of macrophages. • Enhanced phagolysosome fusion by the use of vacuolin1 can increase particle delivery.

Lipase-Responsive Amphotericin B Loaded PCL Nanoparticles for Antifungal Therapies

Amphotericin B is an antifungal drug used for the treatment of invasive fungal infections. However, its clinical use is limited due to its serious side effects, such as renal and cardiovascular toxicity. Furthermore, amphotericin B is administered in high doses due to its poor water solubility. Hence, it is necessary to develop an on-demand release strategy for the delivery of amphotericin B to reduce cytotoxicity. The present report describes a novel encapsulation of amphotericin B into lipase-sensitive polycaprolactone to form a nanocomposite. Nanocomposites were produced by the oil-in-water method and their physicochemical properties such as size, hydrodynamic diameter, drug loading, and zeta potential were determined. The in vitro release of amphotericin B was characterized in the presence and absence of lipase. The antifungal activity of the nanocomposites was verified against lipase-secreting Candida albicans, and cytotoxicity was tested against primary human dermal fibroblasts. In the absence of lipase, the release of amphotericin B from the nanocomposites was minimal. However, in the presence of lipase, an enzyme that is abundant at infection sites, a fungicidal concentration of amphotericin B was released from the nanocomposites. The antifungal activity of the nanocomposites showed an enhanced effect against the lipase-secreting fungus, Candida albicans, in comparison to the free drug at the same concentration. Furthermore, nanoencapsulation significantly reduced amphotericin B-related cytotoxicity compared to the free drug. The synthesized nanocomposites can serve as a potent carrier for the responsive delivery of amphotericin B in antifungal applications.

Limitations of current chemotherapy and future of nanoformulation-based AmB delivery for visceral leishmaniasis-An updated review

Visceral leishmaniasis (VL) is the most lethal of all leishmaniasis diseasesand the second most common parasiticdisease after malaria and,still, categorized as a neglected tropical disease (NTD). According to the latest WHO study, >20 Leishmania species spread 0.7-1.0 million new cases of leishmaniasis each year. VL is caused by the genus, Leishmania donovani (LD), which affects between 50,000 and 90,000 people worldwide each year. Lack of new drug development, increasing drug resistance, toxicity and high cost even with the first line of treatmentof Amphotericin B (AmB), demands new formulation for treatment of VLFurther the lack of a vaccine, allowedthe researchers to develop nanofomulation-based AmB for improved delivery. The limitation of AmB is its kidney and liver toxicity which forced the development of costly liposomal AmB (AmBisome) nanoformulation. Success of AmBisome have inspired and attracted a wide range of AmB nanoformulations ranging from polymeric, solid lipid, liposomal/micellar, metallic, macrophage receptor-targetednanoparticles (NP) and even with sophisticated carbon/quantum dot-based AmBnano delivery systems. Notably, NP-based AmB delivery has shown increased efficacy due to increased uptake, on-target delivery and synergistic impact of NP and AmB. In this review, we have discussed the different forms of leishmaniasis disease and their current treatment options with limitations. The discovery, mechanism of action of AmB, clinical status of AmB and improvement with AmBisome over fungizone (AmB-deoxycholate)for VL treatment was further discussed. At last, the development of various AmB nanoformulation was discussed along with its adavantages over traditional chemotherapy-based delivery.

Synthesis and mechanism-of-action of a novel synthetic antibiotic based on a dendritic system with bow-tie topology

Over the course of the last decades, the continuous exposure of bacteria to antibiotics-at least in parts due to misprescription, misuse, and misdosing-has led to the widespread development of antimicrobial resistances. This development poses a threat to the available medication in losing their effectiveness in treating bacterial infections. On the drug development side, only minor advances have been made to bring forward novel therapeutics. In addition to increasing the efforts and approaches of tapping the natural sources of new antibiotics, synthetic approaches to developing novel antimicrobials are being pursued. In this study, BDTL049 was rationally designed using knowledge based on the properties of natural antibiotics. BDTL049 is a carbosilane dendritic system with bow-tie type topology, which has antimicrobial activity at concentrations comparable to clinically established natural antibiotics. In this report, we describe its mechanism of action on the Gram-positive model organism Bacillus subtilis. Exposure to BDTL049 resulted in a complex transcriptional response, which pointed toward disturbance of the cell envelope homeostasis accompanied by disruption of other central cellular processes of bacterial metabolism as the primary targets of BDTL049 treatment. By applying a combination of whole-cell biosensors, molecular staining, and voltage sensitive dyes, we demonstrate that the mode of action of BDTL049 comprises membrane depolarization concomitant with pore formation. As a result, this new molecule kills Gram-positive bacteria within minutes. Since BDTL049 attacks bacterial cells at different targets simultaneously, this might decrease the chances for the development of bacterial resistances, thereby making it a promising candidate for a future antimicrobial agent.

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.

Application of Nanoparticles in Tumour Targeted Drug Delivery and Vaccine

Cancer is a major cause of death worldwide, and nearly 1 in 6 deaths each year is caused by cancer. Traditional cancer treatment strategies cannot completely solve cancer recurrence and metastasis. With the development of nanotechnology, the study of nanoparticles (NPs) has gradually become a hotspot of medical research. NPs have various advantages. NPs exploit the enhanced permeability and retention (EPR) of tumour cells to achieve targeted drug delivery and can be retained in tumours long-term. NPs can be used as a powerful design platform for vaccines as well as immunization enhancers. Liposomes, as organic nanomaterials, are widely used in the preparation of nanodrugs and vaccines. Currently, most of the anticancer drugs that have been approved and entered clinical practice are prepared from lipid materials. However, the current clinical conversion rate of NPs is still extremely low, and the transition of NPs from the laboratory to clinical practice is still a substantial challenge. In this paper, we review the in vivo targeted delivery methods, material characteristics of NPs and the application of NPs in vaccine preparation. The application of nanoliposomes is also emphasized. Furthermore, the challenges and limitations of NPs are briefly discussed.

Meglumine Antimoniate-Loaded Aqueous-Core PLA Nanocapsules: Old Drug, New Formulation against Leishmania-Related Diseases

Leishmaniasis is a human and animal disease endemic in tropical and subtropical areas treated by means of pentavalent antimony as first-line approach. Unfortunately, the formulations available on the market are characterized by significant side effects and a total remission of the disease is difficult to be obtained. The aim of this investigation is to describe the development and characterization of aqueous-core poly-l-lactide (PLA) nanocapsules containing glucantime (meglumine antimoniate, MA) with the aim of increasing the pharmacological efficacy of the active compound. The polymeric systems characterized by a mean diameter of ≈300 nm exert a great interaction with murine macrophages. MA-loaded PLA nanocapsules show a great antileishmanial activity on mice infected with Leishmania infantum with respect to the free drug, favoring a decrease of the administration times. The biodistribution profiles demonstrate a lower renal accumulation of MA after its nanoencapsulation and a significant increase of its plasmatic half-life. The parasite load evaluated by immunohistochemistry shows a significant decrease in liver, spleen, and kidneys when mice are treated with MA-loaded PLA nanocapsules especially after 45 days. The obtained results demonstrate the potential application of MA-loaded PLA nanocapsules as novel nanomedicine for the treatment of leishmaniasis.

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.

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.

Recent Advances of Taxol-Loaded Biocompatible Nanocarriers Embedded in Natural Polymer-Based Hydrogels

The discovery of paclitaxel (PTX) has been a milestone in anti-cancer therapy and has promoted the development and marketing of various formulations that have revolutionized the therapeutic approach towards several malignancies. Despite its peculiar anti-cancer activity, the physico-chemical properties of PTX compromise the administration of the compound in polar media. Because of this, since the development of the first Food and Drug Administration (FDA)-approved formulation (Taxol®), consistent efforts have been made to obtain suitable delivery systems able to preserve/increase PTX efficacy and to overcome the side effects correlated to the presence of some excipients. The exploitation of natural polymers as potential materials for drug delivery purposes has favored the modulation of the bioavailability and the pharmacokinetic profiles of the drug, and in this regard, several formulations have been developed that allow the controlled release of the active compound. In this mini-review, the recent advances concerning the design and applications of natural polymer-based hydrogels containing PTX-loaded biocompatible nanocarriers are discussed. The technological features of these formulations as well as the therapeutic outcome achieved following their administration will be described, demonstrating their potential role as innovative systems to be used in anti-tumor therapy.

Biodegradable Polymeric Nanoparticles for Drug Delivery to Solid Tumors

Advances in nanotechnology have favored the development of novel colloidal formulations able to modulate the pharmacological and biopharmaceutical properties of drugs. The peculiar physico-chemical and technological properties of nanomaterial-based therapeutics have allowed for several successful applications in the treatment of cancer. The size, shape, charge and patterning of nanoscale therapeutic molecules are parameters that need to be investigated and modulated in order to promote and optimize cell and tissue interaction. In this review, the use of polymeric nanoparticles as drug delivery systems of anticancer compounds, their physico-chemical properties and their ability to be efficiently localized in specific tumor tissues have been described. The nanoencapsulation of antitumor active compounds in polymeric systems is a promising approach to improve the efficacy of various tumor treatments.

Lipid nanoparticles for amphotericin delivery in the treatment of American tegumentary leishmaniasis

Leishmaniasis occurs in the five continents and represents a serious public health challenge, but is still a neglected disease, and the current pharmacological weaponry is far from satisfactory. Triglyceride-rich nanoparticles mimicking chylomicrons (TGNP) behave metabolically like native chylomicrons when injected into the bloodstream. Previously we have shown that TGNP as vehicle to amphothericin B (AB) for treatment of fungi infection showed reduced renal toxicity and lower animal death rates compared to conventional AB. The aim of the current study was to test the tolerability and effectiveness of the TGNP-AB preparation in a murine model of Leishmania amazonensis infection. The in vitro assays determined the cytotoxicity of TGNP-AB, AB, and TGNP in macrophages and promastigote forms and the leishmanicidal activity in infected macrophages. The in vivo toxicity tests were performed in healthy mice with increasing doses of TGPN-AB and AB. Then, animals were treated with 2.5 mg/kg/day of AB, 17.5 mg/kg/day of TGNP-AB, or TGNP three times a week for 4 weeks. TGNP-AB formulation was less cytotoxic for macrophages than AB. TGNP-AB was more effective than AB against the promastigotes forms of the parasite and more effective in reducing the number of infected macrophages and the number of amastigotes forms per cell. TGNP-AB-treated animals showed lower hepatotoxicity. In addition, TGNP-AB group showed a marked reduction in lesion size on the paws and parasitic load. The TGNP-AB preparation attained excellent leishmanicidal activity with remarkable lower drug toxicity at very high doses that, due to the toxicity-buffering properties of the nanocarrier, become fully tolerable.

Evaluation of in vitro and in vivo Efficacy of a Novel Amphotericin B-Loaded Nanostructured Lipid Carrier in the Treatment of Leishmania braziliensis Infection

Background

Leishmaniasis is a neglected disease, and the current therapeutic arsenal for its treatment is seriously limited by high cost and toxicity. Nanostructured lipid carriers (NLCs) represent a promising approach due to high drug loading capacity, controlled drug release profiles and superior stability. Here, we explore the efficacy of a unique pH-sensitive amphotericin B-loaded NLC (AmB-NLC) in Leishmania braziliensis infection in vitro and in vivo.

Methods and Results

AmB-NLC was assessed by dynamic light scattering and atomic force microscopy assays. The carrier showed a spherical shape with a nanometric size of 242.0 ± 18.3 nm. Zeta potential was suggestive of high carrier stability (−42.5 ± 1.5 mV), and the NLC showed ~99% drug encapsulation efficiency (EE%). In biological assays, AmB-NLC presented a similar IC₅₀ as free AmB and conventional AmB deoxycholate (AmB-D) (11.7 ± 1.73; 5.3 ± 0.55 and 13 ± 0.57 ng/mL, respectively), while also presenting higher selectivity index and lower toxicity to host cells, with no observed production of nitric oxide or TNF-α by in vitro assay. Confocal microscopy revealed the rapid uptake of AmB-NLC by infected macrophages after 1h, which, in association with more rapid disruption of AmB-NLC at acidic pH levels, may directly affect intracellular parasites. Leishmanicidal effects were evaluated in vivo in BALB/c mice infected in the ear dermis with L. braziliensis and treated with a pentavalent antimonial (Sb⁵⁺), liposomal AmB (AmB-L) or AmB-NLC. After 6 weeks of infection, AmB-NLC treatment resulted in smaller ear lesion size in all treated mice, indicating the efficacy of the novel formulation.

Conclusion

Here, we preliminarily demonstrate the effectiveness of an innovative and cost-effective AmB-NLC formulation in promoting the killing of intracellular L. braziliensis. This novel carrier system could be a promising alternative for the future treatment of cutaneous leishmaniasis.

Amphotericin B Specifically Induces the Two-Component System LnrJK: Development of a Novel Whole-Cell Biosensor for the Detection of Amphotericin-Like Polyenes

The rise of drug-resistant fungal pathogens urges for the development of new tools for the discovery of novel antifungal compounds. Polyene antibiotics are potent agents against fungal infections in humans and animals. They inhibit the growth of fungal cells by binding to sterols in the cytoplasmic membrane that subsequently causes pore formation and eventually results in cell death. Many polyenes are produced by Streptomycetes and released into the soil environment, where they can then target fungal hyphae. While not antibacterial, these compounds could nevertheless be also perceived by bacteria sharing the same habitat and serve as signaling molecules. We therefore addressed the question of how polyenes such as amphotericin B are perceived by the soil bacterium, Bacillus subtilis. Global transcriptional profiling identified a very narrow and specific response, primarily resulting in strong upregulation of the lnrLMN operon, encoding an ABC transporter previously associated with linearmycin resistance. Its strong and specific induction prompted a detailed analysis of the lnrL promoter element and its regulation. We demonstrate that the amphotericin response strictly depends on the two-component system LnrJK and that the target of LnrK-dependent gene regulation, the lnrLMN operon, negatively affects LnrJK-dependent signal transduction. Based on this knowledge, we developed a novel whole-cell biosensor, based on a P_lnrL-lux fusion reporter construct in a lnrLMN deletion mutant background. This highly sensitive and dynamic biosensor is ready to be applied for the discovery or characterization of novel amphotericin-like polyenes, hopefully helping to increase the repertoire of antimycotic and antiparasitic polyenes available to treat human and animal infections.

Formulation, characterization and in vitro anti-leishmanial evaluation of amphotericin B loaded solid lipid nanoparticles coated with vitamin B12-stearic acid conjugate

Despite the advancement of new anti-leishmanials, amphotericin B (AmB) prevails as one of the most potent agent in the treatment of visceral leishmaniasis (VL), a neglected tropical disease affecting mostly poverty ridden and underdeveloped regions of the globe. Nonetheless, many patients display intolerance to parenteral AmB, notably at higher dosages. Also, conventional AmB presents an apparently poor absorption. Therefore, to improve AmB bioavailability and overcome multiple barriers for oral delivery of AmB, we fabricated a promising vitamin B₁₂-stearic acid (VBS) conjugate coated solid lipid nanoparticles (SLNs) encapsulated with AmB (VBS-AmB-SLNs) by a combination of double emulsion solvent evaporation and thermal sensitive hydrogel techniques. VBS-AmB-SLNs showed a particle size of 306.66 ± 3.35 nm with polydispersity index of 0.335 ± 0.08 while the encapsulation efficiency and drug loading was observed to be 97.99 ± 1.6% and 38.5 ± 5.6% respectively. In vitro drug release showed a biphasic release pattern and chemical stability of AmB was ensured against simulated gastrointestinal fluids. Cellular uptake studies confirmed complete internalization of the formulation. Anti-leishmanial evaluation against intramacrophage amastigotes showed an enhanced efficacy of 94% which was significantly (P < 0.01) higher than conventional AmB without showing any toxic effects on J774A.1 cells. VBS-AmB-SLNs could serve as a potential therapeutic strategy against VL.

Burgeoning Polymer Nano Blends for Improved Controlled Drug Release: A Review

With continual rapid developments in the biomedical field and understanding of the important mechanisms and pharmacokinetics of biological molecules, controlled drug delivery systems (CDDSs) have been at the forefront over conventional drug delivery systems. Over the past several years, scientists have placed boundless energy and time into exploiting a wide variety of excipients, particularly diverse polymers, both natural and synthetic. More recently, the development of nano polymer blends has achieved noteworthy attention due to their amazing properties, such as biocompatibility, biodegradability and more importantly, their pivotal role in controlled and sustained drug release in vitro and in vivo. These compounds come with a number of effective benefits for improving problems of targeted or controlled drug and gene delivery systems; thus, they have been extensively used in medical and pharmaceutical applications. Additionally, they are quite attractive for wound dressings, textiles, tissue engineering, and biomedical prostheses. In this sense, some important and workable natural polymers (namely, chitosan (CS), starch and cellulose) and some applicable synthetic ones (such as poly-lactic-co-glycolic acid (PLGA), poly(lactic acid) (PLA) and poly-glycolic acid (PGA)) have played an indispensable role over the last two decades for their therapeutic effects owing to their appealing and renewable biological properties. According to our data, this is the first review article highlighting CDDSs composed of diverse natural and synthetic nano biopolymers, blended for biological purposes, mostly over the past five years; other reviews have just briefly mentioned the use of such blended polymers. We, additionally, try to make comparisons between various nano blending systems in terms of improved sustained and controlled drug release behavior.

Amphotericin B Loaded Polymeric Nanoparticles for Treatment of Leishmania Infections

Fungal infections in immune-compromised patients are an important cause of mortality and morbidity. Amphotericin B (Amp B) is considered a powerful fungicidal drug but its clinical usage has certain limitations when administered intravenously due to its toxicity and poor solubility. In consideration of such challenges, in cutaneous leishmaniasis, the topical application of Amp B can be a safer option in many aspects. Thus, herein, biopolymer of polycaprolactone (PCL) nanoparticles (NPs) were developed with the loading of Amp B by nanoprecipitation for the treatment of topical leishmanial infections. Various parameters, such as concentration of PCL and surfactant Poloxamer 407, were varied in order to optimize the formation of nanoparticles for the loading of Amp B. The optimized formulation exhibited a mean hydrodynamic particle size of 183 nm with a spherical morphology and an encapsulation efficiency of 85%. The applications of various kinetic models reveal that drug release from nanoformulation follows Korsmeyer-Peppas kinetics and has a high diffusion exponent at a physiological pH of 7.4 as well a skin relevant pH = 5.5. The activity of the prepared nanoparticles was also demonstrated in Leishmania infected macrophages. The measured IC₅₀ of the prepared nanoparticle formulation was observed to be significantly lower when compared to control free Amp B and AmBisome^® for both L. tropica KWH23 and L. donovani amastigotes in order to demonstrate maximum parasite inhibition. The prepared topical nanoformulations are capable of providing novel options for the treatment of leishmaniasis, which can be possible after in vivo assays as well as the establishment of safety profiles.

Antitumor Features of Vegetal Protein-Based Nanotherapeutics

The introduction of nanotechnology into pharmaceutical application revolutionized the administration of antitumor drugs through the modulation of their accumulation in specific organs/body compartments, a decrease in their side-effects and their controlled release from innovative systems. The use of plant-derived proteins as innovative, safe and renewable raw materials to be used for the development of polymeric nanoparticles unlocked a new scenario in the drug delivery field. In particular, the reduced size of the colloidal systems combined with the peculiar properties of non-immunogenic polymers favored the characterization and evaluation of the pharmacological activity of the novel nanoformulations. The aim of this review is to describe the physico-chemical properties of nanoparticles composed of vegetal proteins used to retain and deliver anticancer drugs, together with the most important preparation methods and the pharmacological features of these potential nanomedicines.

PGlu-Modified Nanocrystalline Cellulose Improves Mechanical Properties, Biocompatibility, and Mineralization of Polyester-Based Composites

The development of biocompatible composite materials is in high demand in many fields such as biomedicine, bioengineering, and biotechnology. In this study, two series of poly (D,L-lactide) and poly (ε-caprolactone)-based films filled with neat and modified with poly (glutamic acid) (PGlu) nanocrystalline cellulose (NCC) were prepared. An analysis of scanning electron and atomic force microscopies' results shows that the modification of NCC with poly (glutamic acid) favored the better distribution of the nanofiller in the polymer matrix. Investigating the ability of the developed materials to attract and retain calcium ions led to the conclusion that composites containing NCC modified with PGlu induced better mineralization from model solutions than composites containing neat NCC. Moreover, compared to unmodified NCC, functionalization with PGlu improved the mechanical properties of composite films. The subcutaneous implantation of these composite materials into the backs of rats and the further histological investigation of neighboring tissues revealed the better biocompatibility of polyester materials filled with NCC-PGlu.

Paromomycin-loaded mannosylated chitosan nanoparticles: Synthesis, characterization and targeted drug delivery against leishmaniasis

Cutaneous leishmaniasis is the most common form of leishmaniasis caused by different species of Leishmania parasites. The emergence of resistance, toxicity, long term treatment, high cost of the current drugs, and intracellular nature of the parasite are the major difficulties for the treatment of leishmaniasis. Although the therapeutic effect of paromomycin (PM) on leishmaniasisLeishmania parasite). PM-loaded into mannosylated CS (MCS) nanoparticles using dextran (PM-MCS-dex-NPs) was prepared by ionic gelation and then characterized. The particle size and Zeta potential of PM-MCS-dex-NPs were obtained as 246 nm and + 31 mV, respectively. Mannosylation of CS was qualitatively evaluated by Fourier-transform infrared spectroscopy and quantitatively measured by CHNO elemental analysis; also, a mannosylation level of 17% (w) was attained. Encapsulation efficiency (EE), drug release profile, and THP-1 cell uptake potential were determined. A value of 83.5% for EE and a higher release rate in acidic media were achieved. THP-1 cell uptake level of PM-MCS-dex-NPs after 6 h was ˜2.8 and ˜3.9 times of non-mannosylated CS nanoparticles (PM-CS-dexIn vitroGlucantim, PM-CS-dex-NPs, and PM-MCS-dex-NPs after 48 h were obtained as 1846 ± 158, 1234 ± 93, 784 ± 52 and 2714 ± 126 μg mL^-1Glucantim, PM-CS-dex-NPs, and PM-MCS-dex-NPs after 48 h were obtained as 105.0 ± 14.0, 169.5 ± 9.8, 65.8 ± 7.3 and 17.8 ± 1.0 μg mL^-1Glucantim, PM-CS-dex-NPs and PM-MCS-dexGlucantim, PM-CS-dex-NPs, and PM-MCS-dex-NPs at a typical concentration of 20 μg mL^-1 were 71.78, 69.94, 83.14 and 33.41%, respectively. While the effect of PM-CS-dex-NPs was more salient on amastigotes, PM-MCS-dex-NPs effectively affected both stages of the parasite, especially the amastigote one. This indicated that the mannosylated formulation acts as a targeted delivery system. The findings of this study revealed that this novel targeted formulation represented a strong anti-leishmanial activity.

Paromomycin-loaded mannosylated chitosan nanoparticles: Synthesis, characterization and targeted drug delivery against leishmaniasis

Cutaneous leishmaniasis is the most common form of leishmaniasis caused by different species of Leishmania parasites. The emergence of resistance, toxicity, long term treatment, high cost of the current drugs, and intracellular nature of the parasite are the major difficulties for the treatment of leishmaniasis. Although the therapeutic effect of paromomycin (PM) on leishmaniasis has been investigated in different studies, it has a low oral absorption and short half-life, leading to a decreased drug efficacy. Therefore, new and targeted carriers with no such problems are needed. In the present study, PM was loaded into chitosan (CS) nanoparticles accompanied by targeting to macrophages (as the host of Leishmania parasite). PM-loaded into mannosylated CS (MCS) nanoparticles using dextran (PM-MCS-dex-NPs) was prepared by ionic gelation and then characterized. The particle size and zeta potential of PM-MCS-dex-NPs were obtained as 246 nm and +31 mV, respectively. Mannosylation of CS was qualitatively evaluated by Fourier-transform infrared spectroscopy and quantitatively measured by CHNO elemental analysis; also, a mannosylation level of 17% (w) was attained. Encapsulation efficiency (EE), drug release profile, and THP-1 cell uptake potential were determined. A value of 83.5% for EE and a higher release rate in acidic media were achieved. THP-1 cell uptake level of PM-MCS-dex-NPs after 6 h was ˜2.8 and ˜3.9 times of non-mannosylated CS nanoparticles (PM-CS-dex-NPs) and PM aqueous solution, respectively. In vitro cell cytotoxicity and promastigote and amastigote viabilities were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Half-maximal inhibitory concentration values toward the THP-1 cells for PM aqueous solution, Glucantim, PM-CS-dex-NPs, and PM-MCS-dex-NPs after 48 h were obtained as 1846 ± 158, 1234 ± 93, 784 ± 52 and 2714 ± 126 μg mL^-1, respectively. Half-maximal inhibitory concentration values toward the promastigotes for PM aqueous solution, Glucantim, PM-CS-dex-NPs, and PM-MCS-dex-NPs after 48 h were obtained as 105.0 ± 14.0, 169.5 ± 9.8, 65.8 ± 7.3 and 17.8 ± 1.0 μg mL^-1, respectively. Selectivity (therapeutic) indices for PM aqueous solution, Glucantim, PM-CS-dex-NPs and PM-MCS-dex-NPs after 48 h were obtained as 24.6, 17.5, 3.7 and 214, respectively. The parasite burden in THP-1 cells after 48 h treatment with PM aqueous solution, Glucantim, PM-CS-dex-NPs, and PM-MCS-dex-NPs at a typical concentration of 20 μg mL^-1 were 71.78, 69.94, 83.14 and 33.41%, respectively. While the effect of PM-CS-dex-NPs was more salient on amastigotes, PM-MCS-dex-NPs effectively affected both stages of the parasite, especially the amastigote one. This indicated that the mannosylated formulation acts as a targeted delivery system. The findings of this study revealed that this novel targeted formulation represented a strong anti-leishmanial activity.

Preparation of Sesquiterpene Lactone-Loaded PLA Nanoparticles and Evaluation of Their Antitrypanosomal Activity

Human African trypanosomiasis (HAT), also commonly known as sleeping sickness, is a neglected tropical disease affecting millions of people in poorly developed regions in sub-Saharan Africa. There is no satisfactory treatment for this infection. The investment necessary to bring new drugs to the market is a big deterrent to drug development, considering that the affected communities form a non-lucrative sector. However, natural products and many sesquiterpene lactones (STLs) in particular are very strong trypanocides. Research and applications of nano-drug delivery systems such as nanoparticles (NPs) have undergone unprecedented growth in the recent past. This is mainly due to the advantages offered by these systems, such as targeted delivery of the drug to the place of action (cell, parasite, etc), sustained release of the drug, increased bioavailability, reduced drug dosage, and reduction of undesired side effects, among others. In this study, the STLs α-santonin, arglabin, schkuhrin II, vernolepin, and eucannabinolide, all trypanocides, were loaded into polylactic acid (PLA) NPs through an emulsification-diffusion method. The NPs were stable, homogenous, and spherical in shape with a rounded knotty depression like a navel orange. The average particle sizes were 202.3, 220.3, 219.5, 216.9, and 226.4 nm for α-santonin, arglabin, schkuhrin II, vernolepin, and eucannabinolide, respectively. The NPs had encapsulation efficiencies of 94.6, 78.1, 76.8, 60.7, and 78.9% for α-santonin, arglabin, schkuhrin II, vernolepin, and eucannabinolide, respectively. The NPs loaded with arglabin, vernolepin, and eucannabinolide exhibited considerable antitrypanosomal activity against Trypanosoma brucei rhodesiense (Tbr) with free drug equivalent IC₅₀ values of 3.67, 1.11 and 3.32 µM, respectively. None of the NP formulations displayed cytotoxicity towards mammalian cells (rat skeletal myoblast cell line L6). These results provide new insights into the possibility of incorporating STLs into nanoparticles, which may provide new options for their formulation in order to develop new drugs against HAT.

Lipsosomal amphotericin B: a review of its properties, function, and use for treatment of cutaneous leishmaniasis

The genus Leishmania includes a number of protozoan parasites that cause a wide range of infections named leishmaniasis. Leishmaniasis may be appear in three clinical forms — cutaneous (CL), visceral, and mucocutaneous (MCL) — with variation in their presentation and severity: diffuse CL and post–kala-azar dermal leishmaniasis). The prevalent signs of CL are nonhealing ulcers on exposed skin, but infected patients may have other dermatologic symptoms. In the 1960s, amphotericin B deoxycholate was introduced as a second-line therapy for CL and MCL. However, widespread administration of the agent was prevented, due to its renal and systemic toxicity, high price, and obstacles to intravenous use in leishmaniasis-endemic regions. Amphotericin B binds to ergosterol in the photogenic cell membranes and causes changes in membrane permeability, leakage of ions, and finally cell death. Compared to amphotericin B deoxycholate, a higher dose of liposomal amphotericin B should be administered to show the treatment effect. A high percentage of liposomal amphotericin B is “fastened” in the liposome and not biologically effective. Amphotericin B deoxycholate has some toxic effects, and liposomal amphotericin B is meaningfully less toxic compared to it. Treatment options for CL are limited, due to variation in species causing CL and pharmacokinetic issues. Amphotericin B is effective against some particular forms of CL.

Drug-Loaded Biocompatible Nanocarriers Embedded in Poloxamer 407 Hydrogels as Therapeutic Formulations

Hydrogels are three-dimensional networks of hydrophilic polymers able to absorb and retain a considerable amount of water or biological fluid while maintaining their structure. Among these, thermo-sensitive hydrogels, characterized by a temperature-dependent sol–gel transition, have been massively used as drug delivery systems for the controlled release of various bioactives. Poloxamer 407 (P407) is an ABA-type triblock copolymer with a center block of hydrophobic polypropylene oxide (PPO) between two hydrophilic polyethyleneoxide (PEO) lateral chains. Due to its unique thermo-reversible gelation properties, P407 has been widely investigated as a temperature-responsive material. The gelation phenomenon of P407 aqueous solutions is reversible and characterized by a sol–gel transition temperature. The nanoencapsulation of drugs within biocompatible delivery systems dispersed in P407 hydrogels is a strategy used to increase the local residence time of various bioactives at the injection site. In this mini-review, the state of the art of the most important mixed systems made up of colloidal carriers localized within a P407 hydrogel will be provided in order to illustrate the possibility of obtaining a controlled release of the entrapped drugs and an increase in their therapeutic efficacy as a function of the biomaterial used.