Evaluation of potential acute cardiotoxicity of biodegradable nanocapsules in rats by intravenous administration

Nanoemulsions and nanocapsules loaded with Melaleuca alternifolia essential oil for sepsis treatment

Sepsis represents a complex clinical syndrome that results from a harmful host response to infection. The infections most associated with sepsis are pneumonia, intra-abdominal infection, and urinary tract infection. Tea tree oil (TTO) has shown high antibacterial activity; however, it exhibits low aqueous solubility and high volatility, which have motivated its nanoencapsulation. In this study, the performance of nanoemulsions (NE) and nanocapsules (NC) loaded with TTO was compared. These systems were prepared by spontaneous emulsification and nanoprecipitation methods, respectively. Poly-ε-caprolactone or Eudragit® RS100 were tested as polymers for NCs whereas Tween® 80 or Pluronic® F68 as surfactants in NE preparation. Pluronic® F68 and Eudragit® RS100 resulted in more homogeneous and stable nanoparticles. In accelerated stability studies at 4 and 25 °C, both colloidal suspensions (NC and NE) were kinetically stable. NCs showed to be more stable to photodegradation and less cytotoxic than NEs. After sepsis induction by the cecal ligation and puncture (CLP) model, both NE and NC reduced neutrophil infiltration into peritoneal lavage (PL) and kidneys. Moreover, the systems increased group thiols in the kidney and lung tissue and reduced bacterial growth in PL. Taken together, both systems showed to be effective against injury induced by sepsis; however, NCs should be prioritized due to advantages in terms of cytotoxicity and physicochemical stability.

Oral delivery of ambrisentan-loaded lipid-core nanocapsules as a novel approach for the treatment of pulmonary arterial hypertension

Ambrisentan (AMB) is an orphan drug approved for oral administration that has been developed for the treatment of pulmonary arterial hypertension (PAH), a chronic and progressive pathophysiological state that might result in death if left untreated. Lipid-core nanocapsules (LNCs) are versatile nanoformulations capable of loading lipophilic drugs for topical, vaginal, oral, intravenous, pulmonary, and nasal administration. Our hypothesis was to load AMB into these nanocapsules (LNC_amb) and test their effect on slowing or reducing the progression of monocrotaline-induced PAH in a rat model, upon oral administration. LNC_amb displayed a unimodal distribution of diameters (around 200 nm), negative zeta potential (-11.5 mV), high encapsulation efficiency (78%), spherical shape, and sustained drug release (50-60% in 24 h). The in vivo pharmacodynamic effect of the LNC_amb group was evaluated by observing the echocardiography, hemodynamic, morphometric, and histological data, which showed a significant decrease in PAH in this group, as compared to the control group (AMB_solution). LNC_amb showed the benefit of reversing systolic dysfunction and preventing vascular remodeling with greater efficacy than that observed in the control group. The originality and contribution of our work reveal the promising value of this nanoformulation as a novel therapeutic strategy for PAH treatment.

Design of Pegylated-Nanocapsules to Diphenyl Diselenide Administration: In Vitro Evidence of Hemocompatible and Selective Antiglioma Formulation

Diphenyl diselenide [(PhSe)₂] is a pleiotropic pharmacological agent, but it has low aqueous solubility. The nanoencapsulation of (PhSe)₂ allowed the preparation of an aqueous formulation as well as potentiated its in vitro antitumor effect and the effectiveness in a preclinical model of glioblastoma when administered by the intragastric route. Thus, aiming at maximizing the therapeutic potential of (PhSe)₂, the present study designed a pegylated-formulation intending to intravenous administration of the (PhSe)₂ as a new approach for glioma therapy. The poly(Ɛ-caprolactone) nanocapsules containing (PhSe)₂ were physically coated with polyethyleneglycol (PEG) using the preformed polymer interfacial deposition technique and evaluated through physicochemical, morphological, spectroscopic, and thermal characteristics. Hemocompatibility was determined by the in vitro hemolysis test and cytotoxicity assays were performed in astrocytes and glioma C6 cells (10-100 μM). The pegylated-nanocapsules had an average diameter of 218 ± 25 nm, polydispersity index of 0.164 ± 0.046, zeta potential of - 8.1 ± 1.6 mV, pH 6.0 ± 0.09, (PhSe)₂ content of 102.00 ± 3.57%, and encapsulation efficiency around 98%. Besides, the (PhSe)₂ pegylated-nanocapsules were spherical, presented absence of chemical interaction among the constituents, and showed higher thermal stability than the non-encapsulated materials. PEG-coated nanocapsules did not cause hemolytic effect while formulations without PEG induced a hemolysis rate above 10%. Moreover, pegylated-nanocapsules had superior in vitro antiglioma effect in comparison to free compound (IC₅₀: 24.10 μM and 74.83 μM, respectively). Therefore, the (PhSe)₂-loaded pegylated-nanocapsule suspensions can be considered a hemocompatible formulation for the glioma treatment by the intravenous route.

Toxicity and Safety Evaluation of Doxorubicin-Loaded Cockleshell-Derived Calcium Carbonate Nanoparticle in Dogs

Doxorubicin (DOX) is a potent anticancer agent with cytotoxic effects which limit its clinical usage. This effect is due to its nonselective nature causing injury to the cells as a result of reactive free oxygen radical's release. Cockleshell-derived calcium carbonate nanoparticle (CS-CaCO3NP) is a pH-responsive carrier with targeted delivery potentials. This study aimed at evaluating the toxicity effects of repeated dose administration of DOX-loaded CS-CaCO3NP in healthy dogs. Fifteen dogs with an average body weight of 15 kg were randomized equally into 5 groups. Dogs were subjected to 5 doses at every 3-week interval with (i) normal saline, (ii) DOX, 30 mg/m2, and the experimental groups: CS-CaCO3NP-DOX at (iii) high dose, 50 mg/m2, (iv) clinical dose, 30 mg/m2, and (v) low dose, 20 mg/m2. Radiographs, electrocardiography, and blood samples were collected before every treatment for haematology, serum biochemistry, and cardiac injury assessment. Heart and kidney tissues were harvested after euthanasia for histological and ultrastructural evaluation. The cumulative dose of DOX 150 mg/m2 over 15 weeks revealed significant effects on body weight, blood cells, functional enzymes, and cardiac injury biomarkers with alterations in electrocardiogram, myocardium, and renal tissue morphology. However, the dogs given CS-CaCO3NP-DOX 150 mg/m2 and below did not show any significant change in toxicity biomarker as compared to those given normal saline. The study confirmed the safety of repeated dose administration of CS-CaCO3NP-DOX (30 mg/m2) for 5 cycles in dogs. This finding offers opportunity to dogs with cancer that might require long-term administration of DOX without adverse effects.