Development and in vitro/in vivo evaluation of a novel benznidazole liquid dosage form using a quality-by-design approach

Supramolecular eutectogel as new oral paediatric delivery system to enhance benznidazole bioavailability

Benznidazole (BNZ) serves as the primary drug for treating Chagas Disease and is listed in the WHO Model List of Essential Medicines for Children. Herein, a new child-friendly oral BNZ delivery platform is developed in the form of supramolecular eutectogels (EGs). EGs address BNZ's poor oral bioavailability and provide a flexible twice-daily dose in stick-pack format. This green and sustainable formulation strategy relies on the gelation of drug-loaded Natural Deep Eutectic Solvents (NaDES) with xanthan gum (XG) and water. Specifically, choline chloride-based NaDES form stable and biocompatible 5 mg/mL BNZ-loaded EGs. Rheological and Low-field NMR investigations indicate that EGs are viscoelastic materials comprised of two co-existing regions in the XG network generated by different crosslink distributions between the biopolymer, NaDES and water. Remarkably, the shear modulus and relaxation spectrum of EGs remain unaffected by temperature variations. Upon dilution with simulated gastrointestinal fluids, EGs results in BNZ supersaturation, serving as the primary driving force for its absorption. Interestingly, after oral administration of EGs to rats, drug bioavailability increases by 2.6-fold, with a similar increase detected in their cerebrospinal fluid. The noteworthy correlation between in vivo results and in vitro release profiles confirms the efficacy of EGs in enhancing both peripheral and central BNZ oral bioavailability.

Efficacy of a Zn-based metalorganic framework doped with benznidazole on acute experimental Trypanosoma cruzi infection

Metal-Organic Frameworks (MOFs) have been shown to enhance the activity of encapsulated compounds by facilitating their passage across cell membranes, thereby enabling controlled and selective release. This study investigates the efficacy of BNZ@Zn-MOFs against the acute phase of Trypanosoma cruzi infection in a mouse model. The particles were synthesized by electroelution (EL), doped with BZN via mechanochemistry, and characterized using scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and X-ray diffraction (XRD). BNZ@Zn-MOFs released 80% of the encapsulated BZN within 3 h, demonstrating no cytotoxicity in NIH-3T3 and HeLa cells. Furthermore, in a model of acute experimental T. cruzi-infection in BALB/c mice, the delivery system exhibited antiparasitic activity at a significantly lower BZN concentration compared to free BZN treatment. PCR analysis of treated mice revealed no parasite DNA in their tissues, and hematoxylin-eosin staining showed no apparent damage to tissue architecture. Additionally, serum levels of liver function enzymes remained unchanged, indicating no adverse effects on liver function. This delivery system, utilizing suboptimal BZN doses, enables the preservation of drug activity while potentially facilitating a substantial decrease in side effects associated with Chagas disease treatment.

Preformulation and Long-Term Stability Studies of an Optimized Palatable Praziquantel Ethanol-Free Solution for Pediatric Delivery

To date, the treatment for cysticercosis and neurocysticercosis consists of a single oral intake of praziquantel (5-10 mg/kg), which since it is only available as tablets, hinders its administration to pediatric patients. Praziquantel is a poorly water-soluble drug which represents a challenge for its formulation in solution, particularly for the pediatric population. Thus, this study aimed to develop a palatable solution for praziquantel using pharmaceutical-accepted co-solvent systems. A design of experiments approach was applied to identify the optimal conditions for achieving a suitable amount of praziquantel in solution using co-solvent mixtures. Thus, praziquantel solubility increased from 0.38 up to 43.50 mg/mL in the optimized system. A taste masking assay in healthy human volunteers confirmed a successful reduction of drug bitterness after the addition of selected flavors and a sweetener. Stability studies were also conducted at different temperatures (4, 25, and 40 °C) for 12 months Even though the presence of the three known impurities of praziquantel was observed, their amounts never exceeded the acceptance criteria of the USP. Thus, this novel approach should be considered a valuable alternative for further preclinical studies considering the high prevalence of this infection worldwide.

Formulation of benznidazole-lipid nanocapsules: Drug release, permeability, biocompatibility, and stability studies

Benznidazole, a poorly soluble in water drug, is the first-line medication for the treatment of Chagas disease, but long treatment periods at high dosages cause several adverse effects with insufficient activity in the chronic phase. According to these facts, there is a serious need for novel benznidazole formulations for improving the chemotherapy of Chagas disease. Thus, this work aimed to incorporate benznidazole into lipid nanocapsules for improving its solubility, dissolution rate in different media, and permeability. Lipid nanocapsules were prepared by the phase inversion technique and were fully characterized. Three formulations were obtained with a diameter of 30, 50, and 100 nm and monomodal size distribution with a low polydispersity index and almost neutral zeta potential. Drug encapsulation efficiency was between 83 and 92% and the drug loading was between 0.66 and 1.04%. Loaded formulations were stable under storage for one year at 4 °C. Lipid nanocapsules were found to protect benznidazole in simulated gastric fluid and provide a sustained release platform for the drug in a simulated intestinal fluid containing pancreatic enzymes. The small size and the almost neutral surface charge of these lipid nanocarriers improved their penetration through mucus and such formulations showed a reduced chemical interaction with gastric mucin glycoproteins. LNCs. The incorporation of benznidazole in lipid nanocapsules improved the drug permeability across intestinal epithelium by 10-fold compared with the non-encapsulated drug while the exposure of the cell monolayers to these nanoformulations did not affect the integrity of the epithelium.

3D-Printed Gastroretentive Tablets Loaded with Niclosamide Nanocrystals by the Melting Solidification Printing Process (MESO-PP)

Niclosamide (NICLO) is a recognized antiparasitic drug being repositioned for Helicobacter pylori. The present work aimed to formulate NICLO nanocrystals (NICLO-NCRs) to produce a higher dissolution rate of the active ingredient and to incorporate these nanosystems into a floating solid dosage form to release them into the stomach slowly. For this purpose, NICLO-NCRs were produced by wet-milling and included in a floating Gelucire l3D printed tablet by semi-solid extrusion, applying the Melting solidification printing process (MESO-PP) methodology. The results obtained in TGA, DSC, XRD and FT-IR analysis showed no physicochemical interactions or modifications in the crystallinity of NICLO-NCR after inclusion in Gelucire 50/13 ink. This method allowed the incorporation of NICLO-NCRs in a concentration of up to 25% w/w. It achieved a controlled release of NCRs in a simulated gastric medium. Moreover, the presence of NICLO-NCRs after redispersion of the printlets was observed by STEM. Additionally, no effects on the cell viability of the NCRs were demonstrated in the GES-1 cell line. Finally, gastroretention was demonstrated for 180 min in dogs. These findings show the potential of the MESO-PP technique in obtaining slow-release gastro-retentive oral solid dosage forms loaded with nanocrystals of a poorly soluble drug, an ideal system for treating gastric pathologies such as H. pylori.

Improving the oral delivery of benznidazole nanoparticles by optimizing the formulation parameters through a design of experiment and optimization strategy

Chagas disease is a neglected tropical disease affecting the American continent and also some regions of Europe. Benznidazole, approved by FDA, is a drug of choice but its poor aqueous solubility may lead to a low bioavailability and efficacy. Therefore, the aim of this study was to formulate nanoparticles of benznidazole for improving its solubility, dissolution and permeability. A Plackett-Burman design was applied to identify the effect of 5 factors over 4 responses. Then, a Central Composite design was applied to estimate the values of the most important factors leading to the best compromise between highest nanoprecipitation efficiency, drug solubility and lower particle size. The optimized nanoparticles were evaluated for in vitro drug release in biorelevant media, stability studies and transmission electron microscopy. Biocompatibility and permeability of nanoparticles were evaluated on the Caco-2 cell line. The findings of the optimization process indicated that concentration of drug and stabilizer influenced significantly the particle size while concentration of stabilizer and organic/water phase volume ratio mainly influenced the drug solubility. Stability studies suggested that benznidazole nanoparticles were stable after 12 months at different temperatures. Minimal interactions of those nanoparticles and mucin glycoproteins suggested favorable properties to address the intestinal mucus barrier. Cell viability studies confirmed the safety profile of the optimized formulation and showed an increased permeation through the Caco-2 cells. Thus, this study confirmed the suitability of the design of experiment and optimization approach to elucidate critical parameters influencing the quality of benznidazole nanoparticles, which could lead to a more efficient management of Chagas disease by oral route.

Quality-by-design in pharmaceutical development: From current perspectives to practical applications

Current pharmaceutical research directions tend to follow a systematic approach in the field of applied research and development. The concept of quality-by-design (QbD) has been the focus of the current progress of pharmaceutical sciences. It is based on, but not limited, to risk assessment, design of experiments and other computational methods and process analytical technology. These tools offer a well-organized methodology, both to identify and analyse the hazards that should be handled as critical, and are therefore applicable in the control strategy. Once implemented, the QbD approach will augment the comprehension of experts concerning the developed analytical technique or manufacturing process. The main activities are oriented towards the identification of the quality target product profiles, along with the critical quality attributes, the risk management of these and their analysis through in silico aided methods. This review aims to offer an overview of the current standpoints and general applications of QbD methods in pharmaceutical development.

Benznidazole/Poloxamer 407 Solid Dispersion as a New Strategy to Improve the Treatment of Experimental Trypanosoma cruzi Infection

Benznidazole and nifurtimox are the only drugs specifically approved for the treatment of Chagas disease. Both compounds are given orally in tablets, but occasionally are ineffective and cause adverse effects. Benznidazole, the first-line treatment in many countries, is a compound with low solubility in water that is administered at high doses for long periods of time. To improve its solubility, we developed a new liquid formulation on the basis of solid dispersions (SD) using the amphiphilic polymer poloxamer 407. Herein we present data on its trypanocidal performance in mouse models of acute and chronic Trypanosoma cruzi infection. SD at doses of 60 or 15 mg/kg per day given with different administration schedules were compared with the commercial formulation (CF; 50 mg/kg per day) and vehicle. The SD performance was assessed by direct parasitemia, total anti-T. cruzi antibodies, and parasitic burden in tissues after 4 or 6 mo posttreatment. The efficacy of the SD was equivalent to the CF but without manifest side effects and hepatotoxicity. Considering our previous data on solubility, together with these on efficacy, this new liquid formulation represents a promising alternative for the treatment of Chagas disease, particularly in cases when dosing poses a challenge, as in infants.

Orphan Formulations for Pediatric Use: Development and Stability Control of Two Sildenafil Citrate Solutions for the Treatment of Pulmonary Hypertension

Sildenafil citrate causes vasodilatation, relaxation of the smooth muscle, and reduction of pulmonary arterial pressure. The latter property makes sildenafil citrate efficient for the treatment of cardiovascular diseases, including pulmonary arterial hypertension. Pediatric patients with pulmonary arterial hypertension are more susceptible to errors in drug administration than adults because of a lack of suitable drug dosages. Thus, the purpose of this study was to develop stable (chemically and microbiologically) sildenafil citrate drop liquid formulation, suitable for pediatric patients (including diabetics), ensuring safety during preparation and storing and improving palatability by using milk as a carrier for administration. The significant factors that affect the sildenafil solubility were evaluated by applying a Plackett-Burman design using two levels with six variables. The experiment showed that the type of buffer and glycerin content influenced the sildenafil solubility. The developed formulations proved to be stable for 6 months at all three assayed conditions (40± 2°C, 75 ± 5% RH; 25± 2°C, 60 ± 5% RH; and 4 ± 2°C). The microbiological tests fit with the requirement of the pharmacopeia at day 0 and 90 and even more at day 180. Finally, the palatability assay showed that 0.82 mL of the formulation containing buffer phosphate, 20% glycerin, and 4 mg mL^-1 of sildenafil citrate diluted in 4.8 mL milk (which fits the medium pediatric dose) presented similar palatability to milk alone, and no precipitate or turbidity was observed. Graphical abstract.

Efficacy of continuous versus intermittent administration of nanoformulated benznidazole during the chronic phase of Trypanosoma cruzi Nicaragua infection in mice

Background

Benznidazole and nifurtimox are effective drugs used to treat Chagas’ disease; however, their administration in patients in the chronic phase of the disease is still limited, mainly due to their limited efficacy in the later chronic stage of the disease and to the adverse effects related to these drugs.

Objectives

To evaluate the effect of low doses of nanoformulated benznidazole using a chronic model of Trypanosoma cruzi Nicaragua infection in C57BL/6J mice.

Methods

Nanoformulations were administered in two different schemes: one daily dose for 30 days or one dose every 7 days, 13 times.

Results

Both treatment schemes showed promising outcomes, such as the elimination of parasitaemia, a reduction in the levels of T. cruzi-specific antibodies and a reduction in T. cruzi-specific IFN-γ-producing cells, as well as an improvement in electrocardiographic alterations and a reduction in inflammation and fibrosis in the heart compared with untreated T. cruzi-infected animals. These results were also compared with those from our previous work on benznidazole administration, which was shown to be effective in the same chronic model.

Conclusions

In this experimental model, intermittently administered benznidazole nanoformulations were as effective as those administered continuously; however, the total dose administered in the intermittent scheme was lower, indicating a promising therapeutic approach to Chagas’ disease.

Redox Balance Keepers and Possible Cell Functions Managed by Redox Homeostasis in Trypanosoma cruzi

The toxicity of oxygen and nitrogen reactive species appears to be merely the tip of the iceberg in the world of redox homeostasis. Now, oxidative stress can be seen as a two-sided process; at high concentrations, it causes damage to biomolecules, and thus, trypanosomes have evolved a strong antioxidant defense system to cope with these stressors. At low concentrations, oxidants are essential for cell signaling, and in fact, the oxidants/antioxidants balance may be able to trigger different cell fates. In this comprehensive review, we discuss the current knowledge of the oxidant environment experienced by T. cruzi along the different phases of its life cycle, and the molecular tools exploited by this pathogen to deal with oxidative stress, for better or worse. Further, we discuss the possible redox-regulated processes that could be governed by this oxidative context. Most of the current research has addressed the importance of the trypanosomes' antioxidant network based on its detox activity of harmful species; however, new efforts are necessary to highlight other functions of this network and the mechanisms underlying the fine regulation of the defense machinery, as this represents a master key to hinder crucial pathogen functions. Understanding the relevance of this balance keeper program in parasite biology will give us new perspectives to delineate improved treatment strategies.

Nanocarriers for effective delivery of benznidazole and nifurtimox in the treatment of chagas disease: A review

Neglected tropical diseases (NTDs) constitute a group of infectious diseases prevalent in countries with tropical and subtropical climate that affect the poorest individuals and produce high chronic disability associated with serious problems for the health system and socioeconomic development. Chagas disease or American trypanosomiasis is included on the NTDs list. However, even though this disease affects more than 10 million people, mostly in Latin America, causing the death of over 10,000 people every year, only two drugs are approved for its treatment, benznidazole and nifurtimox. These antiparasitic agents were developed almost half a century ago and present several biopharmaceutical disadvantages such as low aqueous solubility and permeability limiting their bioavailability. In addition, both therapeutic agents are available only as tablets and a liquid pediatric formulation is still lacking. Therefore, novel pharmaceutical strategies to optimize the pharmacotherapy of Chagas disease are urgently required. In this regard, nanotechnological approaches may be a crucial alternative for the delivery of both drugs ensuring an effective pharmacotherapy although the successful bench-to-bedside translation remains a major challenge. The present work reviews in detail the formulation and in-vitro/in-vivo analysis of different nanoformulations of nifurtimox and benznidazole in order to enhance their solubility, dissolution, bioavailability and trypanocidal activity.

Technological innovation strategies for the specific treatment of Chagas disease based on Benznidazole

Caused by Trypanosoma cruzi, Chagas disease is responsible for public health problems greater in magnitude than those attributed to malaria, schistosomiasis, or leishmaniasis. A factor in the socioeconomic development of poor countries, Chagas disease can cause death due to a high parasitic burden during its acute phase due and irreversible damage in organs such as the heart, esophagus, and colon during its chronic phase, even when the number of parasites is minimal. For treating Chagas disease, benznidazole (BNZ) remains the drug of choice and, in Latin America, the only drug on the market for treating the disease. However, BNZ has exhibited insufficient activity in the chronic phase of Chagas disease, required administration in large doses, prolonged treatment, and shown a high incidence of adverse reactions (vomiting, rash, peripheral neuropathy, and spinal cord depression), toxicity, and low solubility in water. As an antidote, pharmaceutical technologies have been introduced that can improve BNZ's solubility and dissolution, as well as reduce side effects in light of its bioavailability, all of which can enhance therapy for Chagas disease. In response to that trend, by conducting a literature review, we sought to identify current pharmaceutical technologies used in tandem with BNZ to improve therapy for Chagas disease. Documented techniques include emulsion and microemulsion formation, solutions, parenteral formulas, micronization, and drug delivery systems supported by the development of nanoparticles and cyclodextrins, solid dispersions, and the use of metal-organic frameworks as innovative excipients. Such technologies increase the water solubility of BNZ by 4-25-fold on dissolution and an 85% release with efficacy in only a few minutes, as recorded during a viability experiment with nanoparticle suspensions. That experiment demonstrated the need for a lower concentration of BNZ to kill 50% of trypomastigote forms of T. cruzi, described in terms of the formation of BNZ-cyclodextrin complexes, and modulating and vectoring of the antichagasic by using metal-organic frameworks. Altogether, the promising results of research identified can enable strategies to improve solubility and efficacy of BNZ, as well as therapy for Chagas disease.