Nanoemulsion of atovaquone as a promising approach for treatment of acute and chronic toxoplasmosis

Black seed oil nanoemulsion containing albendazole against protoscoleces of Echinococcus granulosus: An in vivo study on C57BL/6 mice

Objectives

Hydatid cysts are typically treated with albendazole. Nevertheless, this drug has side effects and limited bioavailability. In this study, we aimed to explore a nanoemulsion of black seed oil to enhance the therapeutic efficacy of albendazole in mice with hydatid cysts.

Materials and Methods

The size of the prepared nanoemulsions was characterized using a Zetasizer analyzer. Additionally, the stability of the nanoemulsions was assessed after 45 days. MTT assay was used to compare the cytotoxicity of free albendazole, nanoemulsion containing albendazole, and nanoemulsion without albendazole. Furthermore, infected mice were treated with these preparations, euthanized, and subjected to autopsy examination. Cysts obtained from mice were examined for histopathological features.

Results

ALB-NE (albendazole-loaded nanoemulsion) DLS results were obtained from black seed oil. Freshly prepared ALB-NE showed (d50 = 170 nm), PDI: 0.323, ALB-NE after 45 days storage at 25 ºC were (d50 = 92.4 nm), and ALB-NE after 45 days storage at 45 ºC revealed (d50 = 118 nm). The cytotoxicity of albendazole was reduced when loaded into the nanoemulsion. Moreover, the group treated with nanoemulsion containing albendazole showed a significant decrease in size and number of cysts compared to those receiving free albendazole or nanoemulsion without the drug. Additionally, after 60 days, the nanoemulsion containing albendazole showed 100% survival, while the survival rate was 50% for free albendazole, 75% for nanoemulsion without albendazole, and 37.5% for PBS.

Conclusion

The nanoemulsion containing albendazole can be a promising treatment for hydatid cysts.

Zinc Oxide and Magnesium-Doped Zinc Oxide Nanoparticles Ameliorate Murine Chronic Toxoplasmosis

Toxoplasma gondii causes a global parasitic disease. Therapeutic options for eradicating toxoplasmosis are limited. In this study, ZnO and Mg-doped ZnO NPs were prepared, and their structural and morphological chrematistics were investigated. The XRD pattern revealed that Mg-doped ZnO NPs have weak crystallinity and a small crystallite size. FTIR and XPS analyses confirmed the integration of Mg ions into the ZnO framework, producing the high-purity Mg-doped ZnO nanocomposite. TEM micrographs determined the particle size of un-doped ZnO in the range of 29 nm, reduced to 23 nm with Mg2+ replacements. ZnO and Mg-doped ZnO NPs significantly decreased the number of brain cysts (p < 0.05) by 29.30% and 35.08%, respectively, compared to the infected untreated group. The administration of ZnO and Mg-doped ZnO NPs revealed a marked histopathological improvement in the brain, liver, and spleen. Furthermore, ZnO and Mg-doped ZnO NPs reduced P53 expression in the cerebral tissue while inducing CD31 expression, which indicated a protective effect against the infection-induced apoptosis and the restoration of balance between free radicals and antioxidant defense activity. In conclusion, the study proved these nanoparticles have antiparasitic, antiapoptotic, and angiogenetic effects. Being nontoxic compounds, these nanoparticles could be promising adjuvants in treating chronic toxoplasmosis.

Formulation and evaluation of atovaquone-loaded macrophage-derived exosomes against Toxoplasma gondii: in vitro and in vivo assessment

IMPORTANCE

This study is the first of its kind that suggests exosomes as a nano-carrier loaded with atovaquone (ATQ), which could be considered as a new strategy for improving the effectiveness of ATQ against acute and chronic phases of Toxoplasma gondii.

Co-delivery of beta-caryophyllene and indomethacin in the oily core of nanoemulsions potentiates the anti-inflammatory effect in LPS-stimulated macrophage model

The potentiation of pharmacological effects can be achieved through several strategies, such as the association of substances and delivery in nanostructured systems. In practice, potentiation can be measured by the law of mass action and joint evaluation of the combination index (CI) and dose-response curves. In this context, this study aimed to evaluate the anti-inflammatory effect of the association of β-caryophyllene and indomethacin in the free form and delivered in nanoemulsions using the in vitro model of LPS-stimulated murine macrophage. The results indicated potentiation of the anti-inflammatory effect of nanoemulsified substances compared to free substances, as well as synergistic action between the sesquiterpene and the selected NSAID. In comparison, the association of β-caryophyllene and indomethacin in the free form inhibited the production of nitric oxide by 50% at 48.60 µg/mL (CI = 0.21), while the nanoemulsified association of these substances resulted in an IC50 of 1.45 µg/mL (CI = 0.14). In parallel, cytotoxicity assays on HaCaT and MRC-5 cell lines demonstrated the safety of IC50-equivalent concentrations of the anti-inflammatory action, and no irritating effects on the chorioallantoic membrane of embryonated eggs were observed (HET-CAM assay). The results suggest that β-caryophyllene may be an alternative to replace an inert oily core in nanoemulsion systems when anti-inflammatory effects are desirable.

Mefloquine loaded niosomes as a promising approach for the treatment of acute and chronic toxoplasmosis

Toxoplasmosis is a disease with a worldwide distribution and significant morbidity and mortality. In search of effective treatment, mefloquine (MQ) was repurposed and loaded with niosomes to treat acute and chronic phases of toxoplasmosis in experimental mice. Mice were orally inoculated with 20 cysts of Toxoplasma gondii (ME 49 strain) for the acute model of infection and 10 cysts for the chronic model of infection. Infected mice were dosed with MQ solution or MQ-niosomes at 50 mg/kg/day, starting from the second day post-infection (PI) (acute model) or the fifth week PI (chronic model), and this was continued for six consecutive days. The effects of MQ solution and MQ-niosomes were compared with a pyrimethamine/sulfadiazine (PYR/SDZ) dosing combination as mortality rates, brain cyst number, inflammatory score, and immunohistochemical studies that included an estimation of apoptotic cells (TUNEL assays). In the acute infection model, MQ solution and MQ-niosomes significantly reduced the mortality rate from 45% to 25 and 10%, respectively, compared with infected untreated controls, and decreased the number of brain cysts by 51.5% and 66.9%, respectively. In the chronic infection model, cyst reduction reached 80.9% and 12.3% for MQ solution and MQ-niosomes treatments, respectively. MQ-niosomes significantly decreased inflammation induced by acute or chronic T. gondii infection. Additionally, immunohistochemical analysis revealed that MQ solution and MQ-niosomes significantly increased the number of TUNEL-positive cells in brain tissue, indicative of induction of apoptosis. Collectively, these results indicate that MQ-niosomes may provide a useful delivery strategy to treat both acute and chronic toxoplasmosis.

Anti-rheumatic activity of topical nanoemulsion containing bee venom in rats

PURPOSE

Bee Venom (BV) has been used to treat rheumatoid arthritis (RA) for many centuries. However, its clinical use is limited by pain and fear of bee stings/injection. Nanoemulsions (NEs) are nanocarriers that are able to help their content(s) penetrate through the skin. They also act as drug reservoirs on the skin to provide an efficient, sustained-release vehicle.

METHODS

In this paper, we present the development of a stable water-in-oil NE to help passing BV through the animal skin when used topically.

RESULTS

Particle size of NE was 12.7 to 29.8 nm for NEs containing 0 to 150 µg/ml BV. Also, its anti-inflammatory effects were evaluated in rat models of type II collagen-induced arthritis. Topical administration of NEs containing 18.75 or 9.37 μg/ml BV were able to significantly (p<0.05) reduce inflammation in the rat paws compared to the blank and control groups.

CONCLUSION

Our findings demonstrated the efficacy of NEs containing BV to reduce inflammation caused by RA animal model.

The High Potency of Green Synthesized Copper Nanoparticles to Prevent the Toxoplasma gondii Infection in Mice

PURPOSE

Nowadays, due to the lack of an effective vaccine to prevent the toxoplasmosis, chemotherapy with the combination of pyrimethamine and sulfadiazine is considered as the "gold standard" treatment for toxoplasmosis. Recent reports have exhibited that these synthesized chemical drugs are associated with some serious side effects. The present study aims to evaluate the prophylactic effects of copper nanoparticles (CuNPs) green synthesized by Capparis spinosa fruit methanolic extract alone and combined with atovaquone against chronic toxoplasmosis induced by the Tehran strain of Toxoplasma gondii in mice METHODS: Mice were then orally administrated with CuNPs at the doses of 2 and 4 mg/kg/day and in combined with atovaquone 50 mg/kg for 14 days. Male BALB/c mice were divided into two seven groups include C1 (non-treated non-infected); C2 (treated with normal saline); C3 (Infected mice treated with atovaquone 100 mg/kg/day); Ex1 (treated with CuNPs 2 mg/kg/day); Ex2 (treated with CuNPs 4 mg/kg/day); Ex3 (treated with CuNPs 2 mg/kg/day + atovaquone 50 mg/kg/day); Ex3 (treated with CuNPs 4 mg/kg/day + atovaquone 50 mg/kg/day). On the 15th day, the mice were infected with the intraperitoneal inoculation of 20-25 tissue cysts from the Tehran strain of T. gondii. The mean numbers of brain tissue cysts and the mRNA levels of IL-12, IFN-γ, and inducible nitric oxide synthase (iNOS) in mice of each tested group were measured.

RESULTS

CuNPs were green synthesized by C. spinosa methanolic extract. Scanning electron microscopy showed that the particle size of CuNPs was 17 and 41 nm with maximum peak at the wavelength of 414 nm. The mean number of T. gondii tissue cysts in mice of tested groups of Ex1, Ex2, Ex3, and Ex4, significantly decreased as a dose-dependent response compared with control group. Moreover, in similar to the control group C3, no T. gondii tissue cysts was observed in mice of experimental group Ex3 and Ex4. The mRNA levels of IFN-γ, IL-12, and iNO was measured in mice of all tested groups. The mRNA levels of IFN-γ, IL-12, and iNO was increased in all mice of experimental groups in comparison with the control group C2; however, a significant enhancement was detected in mRNA level of IFN-γ, IL-12, and iNO in the tested groups of Ex3 and Ex4 when compared with control group C3.

CONCLUSION

The obtained results revealed the high potency of CuNPs alone and combined with atovaquone to prevent toxoplasmosis in mice. Although, the prophylactic effects of CuNPs and other properties, such as improved cellular immunity and low toxicity, are positive topics; however, more studies are required to approve these findings especially in clinical settings.

Exploring the powerful phytoarsenal of white grape marc against bacteria and parasites causing significant diseases

Natural extracts containing high polyphenolic concentration possess antibacterial, anti-parasitic and fungicidal activities. The present research characterises two extracts based on white grape marc, a winemaking by-product, describing their physicochemical features and antimicrobial capacities. The main components of these extracts are phenolic acids, flavan-3-ols and their gallates and flavonols and their glycosides. As a result of this complex composition, the extracts showed pronounced bioactivities with potential uses in agricultural, pharmaceutical and cosmetic industries. Polyphenol compounds were extracted by using hydro-organic solvent mixtures from the by-product of Albariño white wines (Galicia, NW Spain) production. The in vitro antimicrobial activity of these extracts was evaluated on Gram-positive and Gram-negative bacteria and Apicomplexan and Oomycota parasites. Microbial species investigated are causing agents of several human and animal diseases, such as foodborne illnesses (Bacillus cereus, Escherichia coli, Salmonella enterica, and Toxoplasma gondii), skin infections and/or mastitis (Staphylococcus aureus and Streptococcus uberis), malaria (Plasmodium falciparum) and plant infections as "chestnut ink" or "root rot" (Phytophthora cinnamomi). Both extracts showed activity against all the tested species, being nontoxic for the host. So, they could be used for the development of biocides to control a wide range of pathogenic agents and contribute to the enhancement of winemaking industry by-products.

Myrtus communis Essential Oil; Anti-Parasitic Effects and Induction of the Innate Immune System in Mice with Toxoplasma gondii Infection

Background: Myrtus communis (M. communis) is a wild aromatic plant used for traditional herbal medicine that can be demonstrated in insecticidal, antioxidant, anti-inflammatory, and antimicrobial activity of its essential oils (MCEO). Aim: The present study aimed to evaluate the prophylactic effects of M. communis essential oil (MCEO) against chronic toxoplasmosis induced by the Tehran strain of Toxoplasma gondii in mice. Methods: Gas chromatography/mass spectrometry (GC/MS) analysis was performed to determine the chemical composition of MCEO. Mice were then orally administrated with MCEO at the doses of 100, 200, and 300 mg/kg/day and also atovaquone 100 mg/kg for 21 days. On the 15th day, the mice were infected with the intraperitoneal inoculation of 20–25 tissue cysts from the Tehran strain of T. gondii. The mean numbers of brain tissue cysts and the mRNA levels of IL-12 and IFN-γ in mice of each tested group were measured. Results: By GC/MS, the major constituents were α-pinene (24.7%), 1,8-cineole (19.6%), and linalool (12.6%), respectively. The results demonstrated that the mean number of T. gondii tissue cysts in experimental groups Ex1 (p < 0.05), Ex2 (p < 0.001) and Ex3 (p < 0.001) was meaningfully reduced in a dose-dependent manner compared with the control group (C2). The mean diameter of tissue cyst was significantly reduced in mice of the experimental groups Ex2 (p < 0.01) and Ex3 (p < 0.001). The results demonstrated that although the mRNA levels of IFN-γ and IL-12 were elevated in all mice of experimental groups, a significant increase (p < 0.001) was observed in tested groups of Ex2 and Ex3 when compared with control groups. Conclusion: The findings of the present study demonstrated the potent prophylactic effects of MCEO especially in the doses 200 and 300 mg/kg in mice infected with T. gondii. Although the exceptional anti-Toxoplasma effects of MCEO and other possessions, such as improved innate immunity and low toxicity are positive topics, there is, however, a need for more proof from investigations in this field.

Levofloxacin nanoemulsion gel has a powerful healing effect on infected wound in streptozotocin-induced diabetic rats

The aim of this study was to develop a novel oil-in-water (o/w) nanoemulsion gel containing levofloxacin for enhanced topical efficacy. Average particle size of sesame oil nanoemulsion without (SONE) and containing levofloxacin (SONEL) was found as 25.2 and 26.3 nm, respectively. Results from scratch test showed that SONEL had better proliferation effect in comparison with negative control. Treated animals with SONEL showed significant reduction in period of epithelialization, wound contraction, and number of inflammatory cells among all groups. Also, SONEL-treated group had the greatest collagen synthesis. Immunohistochemical analysis showed high intensity of CD31 and TGF-β at wound site of treatment groups with SONEL on day 12 post-treatment (P < 0.05). Skin irritation test demonstrated safety of SONEL gel for skin topical application. In conclusion, our studies suggest that SONEL could be an effective formulation for treatment of diabetic wound infection by controlling infection and improving the healing process. Graphical Abstract .

Effective management of acute postoperative pain using intravenous emulsions of novel ketorolac prodrugs: in vitro and in vivo evaluations

The aim was to prepare intravenous fat emulsions (IFEs) of ketorolac (KTL) ester prodrugs and to investigate the pharmacokinetics and pharmacodynamics of these formulations. Three prodrugs of KTL (KTL-IS, KTL-AX and KTL-BT) were synthesized as a means to increase the lipid solubility of KTL. All KTL prodrugs with higher Log P values presented increased tendency to partition into a blank IFE using extemporaneous addition method - the encapsulation efficiency of KTL-IS IFE and KTL-BT IFE was more than 97%. The particle sizes and zeta potentials of these two formulations were comparable to that of the blank IFE. PK studies in rabbits showed significant larger AUC0-8h (646.969 ± 154.326 mg/L•h-1 for KTL-IS IFE and 559.426 ± 103.057 mg/L•h-1 for KTL-BT IFE) than that of ketorolac tromethamine (KTL-T) injectable (286.968 ± 63.045 mg/L•h-1) and approximately 2-fold increases in the elimination t1/2 over KTL-T. In a rat postoperative pain model, the paw withdrawal thresholds and the paw withdrawal latency after I.V. KTL prodrug IFEs were significantly higher than that after I.V. KTL-T at 3~4 h. Effective controlling of acute postoperative pain in a longer duration can be achieved by using non-addictive ketorolac derivatives intraveneous emulsions.

In vitro Evaluation of Mannosylated Paromomycin-Loaded Solid Lipid Nanoparticles on Acute Toxoplasmosis

Toxoplasma gondii is a zoonotic intracellular protozoan with worldwide distribution. Acute and severe toxoplasmosis are commonly reported in patients who suffer from acquired/congenital immune deficiency. This study aimed to synthesize mannosylated paromomycin-loaded solid lipid nanoparticles (PM-SLN-M) and to evaluate them on acute toxoplasmosis. SLN was synthesized and then loaded by 7 mg/mL paromomycin sodium. Mannose coating was performed, and after washing, the size, zeta potential, and loading percentage were calculated. To evaluate the cell toxicity, an MTT assay was performed on Vero cells by different concentrations (log 10^-1) of SLN, PM-SLN-M, and PM-SLN. In addition, the anti-Toxoplasma effects were also evaluated using trypan-blue staining and scanning electron microscopy (SEM). An MTT assay was also employed to evaluate the effects of PM and PM-SLN-M on intracellular Toxoplasma. A 6-month stability test of PM-SLN and PM-SLN-M represented that the characteristics all remained constant. The cell viability assay demonstrated that PM-SLN-M had lower cell toxicity (<20%) compared to PM-SLN (<30%) and PM (<40%). Statistical analysis showed that PM-SLN-M significantly killed ~97.555 ± 0.629 (95% CI: 91.901 to 103.209; P < 0.05) of T. gondii tachyzoites. More than 50% of Toxoplasma-infected Vero cells remained viable in concentrations more than 0.07 μg/mL and 7 μg/mL of PM and PM-SLN-M, respectively. SEM analysis showed that T. gondii tachyzoites were changed in both size and morphology facing with PM-SLN-M. Our findings indicated that synthesized PM-SLN-M had anti-Toxoplasma activity without significant host cell toxicity at the highest concentration. Our study demonstrated that PM was able to kill intracellular Toxoplasma in lower concentration in comparison to PM-SLN-M, although PM-SLN-M showed lower cytotoxic effects on Vero cells.

Green Micro- and Nanoemulsions for Managing Parasites, Vectors and Pests

The management of parasites, insect pests and vectors requests development of novel, effective and eco-friendly tools. The development of resistance towards many drugs and pesticides pushed scientists to look for novel bioactive compounds endowed with multiple modes of action, and with no risk to human health and environment. Several natural products are used as alternative/complementary approaches to manage parasites, insect pests and vectors due to their high efficacy and often limited non-target toxicity. Their encapsulation into nanosystems helps overcome some hurdles related to their physicochemical properties, for instance limited stability and handling, enhancing the overall efficacy. Among different nanosystems, micro- and nanoemulsions are easy-to-use systems in terms of preparation and industrial scale-up. Different reports support their efficacy against parasites of medical importance, including Leishmania, Plasmodium and Trypanosoma as well as agricultural and stored product insect pests and vectors of human diseases, such as Aedes and Culex mosquitoes. Overall, micro- and nanoemulsions are valid options for developing promising eco-friendly tools in pest and vector management, pending proper field validation. Future research on the improvement of technical aspects as well as chronic toxicity experiments on non-target species is needed.

Nanoemulsions in CNS drug delivery: recent developments, impacts and challenges

Despite enormous efforts, treatment of CNS diseases remains challenging. One of the main issues causing this situation is limited CNS access for the majority of drugs used as part of the therapeutic regimens against life-threatening CNS diseases. Regarding the inarguable position of the nanocarrier systems in neuropharmacokinetic enhancement of the CNS drugs, this review discusses the latest findings on nanoemulsions (NEs) as one of the most promising candidates of this type, to overcome the challenges of CNS drug delivery. Future development of NE-based CNS drug delivery needs to consider so many aspects not only from a physicochemical point of view but also related to the biointerface of these very small droplets before achieving clinical value.

Curcumin nanoemulsion as a novel chemical for the treatment of acute and chronic toxoplasmosis in mice

Background

The aim of this study was to prepare curcumin nanoemulsion (CR-NE) to solve the problems associated with poor water solubility and low bioavailability of CR and to test its efficiency in the treatment of acute and chronic toxoplasmosis in mouse models.

Materials and methods

CR-NE 1% was prepared using spontaneous emulsification by soybean as oil phase; a mixture of Tween 80 and Tween 85 as surfactant; ethanol as cosurfactant and distilled water. Particle size and zeta potential of NE were assessed using Nano-ZS90 dynamic light scattering. Stability testing of NE was assessed after storage for 2 months at room temperature. In vivo experiments were carried out using 50 BALB/c mice inoculated with virulent RH strain (type I) and 50 BALB/c mice inoculated with avirulent Tehran strain (type II) of Toxoplasma gondii and treated with CR-NE (1% w/v), CR suspension (CR-S, 1% w/v), and NE without CR (NE-no CR).

Results

The mean particle size and zeta potential of CR-NE included 215.66±16.8 nm and −29.46±2.65 mV, respectively, and were stable in particle size after a three freeze–thaw cycle. In acute phase experiment, the survival time of mice infected with RH strain of T. gondii and treated with CR-NE extended from 8 to 10 days postinoculation. The differences were statistically significant between the survival time of mice in CR-NE-treated group compared with negative control group (P<0.001). Furthermore, CR-NE significantly decreased the mean counts of peritoneum tachyzoites from 5,962.5±666 in negative control group to 627.5±73 in CR-NE-treated mice (P<0.001). Growth inhibition rates of tachyzoites in peritoneum of mice receiving CR-NE, CR-S, and NE-no CR included 90%, 21%, and 11%, respectively, compared with negative control group. In chronic phase experiment, the average number and size of tissue cysts significantly decreased to 17.2±15.6 and 31.5±6.26 µm, respectively, in mice inoculated with bradyzoites of T. gondii Tehran strain and treated with CR-NE compared with that in negative control group (P<0.001). Decrease of cyst numbers was verified by downregulation of BAG1 in treatment groups compared with negative control group with a minimum relative expression in CR-NE (1.12±0.28), CR-S (11.76±0.87), and NE-no CR (14.67±0.77), respectively, (P<0.001).

Conclusion

Results from the current study showed the potential of CR-S and CR-NE in treatment of acute and chronic toxoplasmosis in mouse models for the first time. However, CR-NE was more efficient than CR-S, and it seems that CR-NE has a potential formula for the treatment of acute and chronic toxoplasmosis, especially in those with latent bradyzoites in brain.

A Repurposed Drug for Brain Cancer: Enhanced Atovaquone Amorphous Solid Dispersion by Combining a Spontaneously Emulsifying Component with a Polymer Carrier

Glioblastoma multiforme (GBM) is the most common and lethal central nervous system tumor. Recently, atovaquone has shown inhibition of signal transducer and activator transcription 3, a promising target for GBM therapy. However, it is currently unable to achieve therapeutic drug concentrations in the brain with the currently reported and marketed formulations. The present study sought to explore the efficacy of atovaquone against GBM as well as develop a formulation of atovaquone that would improve oral bioavailability, resulting in higher amounts of drug delivered to the brain. Atovaquone was formulated as an amorphous solid dispersion using an optimized formulation containing a polymer and a spontaneously emulsifying component (SEC) with greatly improved wetting, disintegration, dispersibility, and dissolution properties. Atovaquone demonstrated cytotoxicity against GBM cell lines as well as provided a confirmed target for atovaquone brain concentrations in in vitro cell viability studies. This new formulation approach was then assessed in a proof-of-concept in vivo exposure study. Based on these results, the enhanced amorphous solid dispersion is promising for providing therapeutically effective brain levels of atovaquone for the treatment of GBM.