Surface-dependent endocytosis of poly(isobutylcyanoacrylate) nanoparticles by Trichomonas vaginalis

Locust Bean Gum Nano-Based Hydrogel for Vaginal Delivery of Diphenyl Diselenide in the Treatment of Trichomoniasis: Formulation Characterization and In Vitro Biological Evaluation

Trichomoniasis is the most common nonviral sexually transmitted infection in the world, but its available therapies present low efficacy and high toxicity. Diphenyl diselenide (PhSe₂) is a pharmacologically active organic selenium compound; however, its clinical use is hindered by its lipophilicity and toxicity. Nanocarriers are an interesting approach to overcome the limitations associated with this compound. This study designed and evaluated a vaginal hydrogel containing PhSe₂-loaded Eudragit^® RS100 and coconut oil nanocapsules for the treatment of trichomoniasis. Nanocapsules presented particle sizes in the nanometric range, positive zeta potential, a compound content close to the theoretical value, and high encapsulation efficiency. The nanoencapsulation maintained the anti-Trichomonas vaginalis action of the compound while improving the scavenger action in a DPPH assay. The hydrogels were prepared by thickening nanocapsule suspensions with locust bean gum (3%). The semisolids maintained the nanometric size of the particles and the PhSe₂ content at around the initial concentration (1.0 mg/g). They also displayed non-Newtonian pseudo-plastic behavior and a highly mucoadhesive property. The chorioallantoic membrane method indicated the absence of hemorrhage, coagulation, or lysis. The compound, from both non-encapsulated and nano-based hydrogel delivery systems, remained on the surface of the bovine vaginal mucosa. Therefore, the formulations displayed the intended properties and could be a promising alternative for the treatment of trichomoniasis.

Multiple Roles of Chitosan in Mucosal Drug Delivery: An Updated Review

Chitosan (CS) is a linear polysaccharide obtained by the deacetylation of chitin, which, after cellulose, is the second biopolymer most abundant in nature, being the primary component of the exoskeleton of crustaceans and insects. Since joining the pharmaceutical field, in the early 1990s, CS attracted great interest, which has constantly increased over the years, due to its several beneficial and favorable features, including large availability, biocompatibility, biodegradability, non-toxicity, simplicity of chemical modifications, mucoadhesion and permeation enhancer power, joined to its capability of forming films, hydrogels and micro- and nanoparticles. Moreover, its cationic character, which renders it unique among biodegradable polymers, is responsible for the ability of CS to strongly interact with different types of molecules and for its intrinsic antimicrobial, anti-inflammatory and hemostatic activities. However, its pH-dependent solubility and susceptibility to ions presence may represent serious drawbacks and require suitable strategies to be overcome. Presently, CS and its derivatives are widely investigated for a great variety of pharmaceutical applications, particularly in drug delivery. Among the alternative routes to overcome the problems related to the classic oral drug administration, the mucosal route is becoming the favorite non-invasive delivery pathway. This review aims to provide an updated overview of the applications of CS and its derivatives in novel formulations intended for different methods of mucosal drug delivery.

Effect of micro- and nanoparticle shape on biological processes

In the drug delivery field, there is beyond doubt that the shape of micro- and nanoparticles (M&NPs) critically affects their biological fate. Herein, following an introduction describing recent technological advances for designing nonspherical M&NPs, we highlight the role of particle shape in cell capture, subcellular distribution, intracellular drug delivery, and cytotoxicity. Then, we discuss theoretical approaches for understanding the effect of particle shape on internalization by the cell membrane. Subsequently, recent advances on shape-dependent behaviors of M&NPs in the systemic circulation are detailed. In particular, the interaction of M&NPs with blood proteins, biodistribution, and circulation under flow conditions are analyzed. Finally, the hurdles and future directions for developing nonspherical M&NPs are underscored.

The Expanded Role of Chitosan in Localized Antimicrobial Therapy

Chitosan is one of the most studied natural origin polymers for biomedical applications. This review focuses on the potential of chitosan in localized antimicrobial therapy to address the challenges of current rising antimicrobial resistance. Due to its mucoadhesiveness, chitosan offers the opportunity to prolong the formulation residence time at mucosal sites; its wound healing properties open possibilities to utilize chitosan as wound dressings with multitargeted activities and more. We provide an unbiased overview of the state-of-the-art chitosan-based delivery systems categorized by the administration site, addressing the site-related challenges and evaluating the representative formulations. Specifically, we offer an in-depth analysis of the current challenges of the chitosan-based novel delivery systems for skin and vaginal infections, including its formulations optimizations and limitations. A brief overview of chitosan's potential in treating ocular, buccal and dental, and nasal infections is included. We close the review with remarks on toxicity issues and remaining challenges and perspectives.

Shape stability of ellipsoidal nanomaterials prepared by physical deformation

The nonspherical shape of nanomaterials (NMs) represents a key attribute for controlling their biological behaviors. Analyzing shape stability over time represents a significant concern because nonspherical NMs are likely to rearrange into a thermodynamically more stable spherical shape. In this investigation, ellipsoidal NMs were designed by physical deformation of core/shell nanospheres composed of poly(isobutylcyanoacrylate) and chitosan or a mixture of chitosan and thiolated chitosan. After optimizing the process parameters for designing ellipsoidal NMs, the shape stability during storage was investigated for 6 months at different temperatures (4 °C, 20 °C and 40 °C). The NM shape was examined by analyzing the aspect ratio from images obtained by electron microscopy techniques. The results demonstrated the feasibility of designing shape-persistent ellipsoidal NMs by physical deformation of spherical particles.

Real-time visualization of morphology-dependent self-motion of hyaluronic acid nanomaterials in water

Drug delivery to target sites is often limited by inefficient particle transport through biological media. Herein, motion behaviors of spherical and nonspherical nanomaterials composed of hyaluronic acid were studied in water using real-time multiple particle tracking technology. The two types of nanomaterials have comparable surface compositions and surface potentials, and they have equivalent diameters. The analysis of nanomaterial trajectories revealed that particles with flattened morphology and a high aspect ratio, designated nanoplatelets, exhibited more linear trajectories and faster diffusion in water than nanospheres. Fitting the plots of mean square displacement vs. time scale suggests that nanoplatelets exhibited hyperdiffusive behavior, which is similar to the motion of living microorganisms. Furthermore, at 37 °C, the surface explored by a nanoplatelet was up to 33-fold higher than that explored by a nanosphere. This investigation on morphology-dependent self-motion of nanomaterials could have a significant impact on drug delivery applications by increasing particle transport through biological media.

Role of the interactions of soft hyaluronan nanomaterials with CD44 and supported bilayer membranes in the cellular uptake

Increasing valence by acting on nanomaterial morphology can enhance the ability of a ligand to specifically bind to targeted cells. Herein, we investigated cell internalization of soft hyaluronic acid (HA) nanoplatelets (NPs) that exhibit a typical hexagonal shape, flat surfaces and high aspect ratio (Γ≈12 to 20), as characterized by atomic force microscopy in hydrated conditions. Fluorescence imaging revealed that internalization of HA-NPs by a T24 tumor cell line and by macrophages was higher than native polysaccharide in a dose-dependent and time-dependent manners. The ability of HA-NPs to efficiently compete with native HA assessed using Bio-layer interferometry showed that NPs had a stronger interaction with recombinant CD44 receptor compared to native HA. The results were discussed regarding physical properties of the NPs and the implication of multivalent interactions in HA binding to CD44. Experiments conducted on supported bilayer membranes with different compositions showed that non-specific interactions of NPs with lipid membranes were negligible. Our findings provide insights into intracellular drug delivery using soft HA-NPs through receptor-mediated multivalent interactions.

Chitosan-based systems aimed at local application for vaginal infections

Vaginal administration is a promising route for the local treatment of infectious vaginal diseases since it can bypass the first-pass metabolism, drug interactions, and adverse effects. However, the commercial products currently available for topical vulvovaginal treatment have low acceptability and do not adequately explore this route. Mucoadhesive systems can optimize the efficacy of drugs administered by this route to increase the retention time of the drug in the vaginal environment. Several polymers are used to develop mucoadhesive systems, among them chitosan, a natural polymer that is highly biocompatible and technologically versatile. Thus, the present review aimed to analyze the studies that used chitosan to develop mucoadhesive systems for the treatment of local vaginal infections. These studies demonstrated that chitosan as a component of mucoadhesive drug delivery systems (DDS) is a promising device for the treatment of vaginal infectious diseases, due to the intrinsic antimicrobial activity of this biopolymer and because it does not interfere with the effectiveness of the drugs used for the treatment.

Gellan gum-based hydrogel containing nanocapsules for vaginal indole-3-carbinol delivery in trichomoniasis treatment

Trichomonas vaginalis infection is the STI most common worldwide. Indole-3-carbinol (I3C) is a phytochemical presenting promising biological activities. In this study, design, formulation, and evaluation of a vaginal hydrogel containing I3C-loaded nanocapsules for the treatment of trichomoniasis have been investigated. Nanocapsules of Eudragit® RS100 and rosehip oil containing I3C (NC-I3C) were prepared by interfacial deposition of preformed polymer method. In vitro evaluations showed that free I3C (IC50 = 3.36 µg/mL) was able to reduce the trophozoites viability at higher concentrations (3.13 and 6.25 µg/mL), while nanoencapsulation (IC50 = 2.09 µg/mL) reduced the viability at all concentrations evaluated. Comparing free and nanoencapsulated I3C, we observe that nanoencapsulation improved anti-T. vaginalis activity. In order to obtain a formulation for vaginal administration, hydrogels (HG-NC-I3C) were prepared by thickening the NC-I3C with gellan gum. HG-NC-I3C presented particle size below 195 nm, low polydispersity index (<0.2), I3C content = 0.50 ± 0.01 mg/g, pH = 7.05, non-Newtonian pseudoplastic flow behavior and exhibited mucoadhesion to cow's vaginal mucosa. Evaluation of irritation potential by chorioallantoic membrane method indicated that the formulations are considered non-irritating. Besides that, permeation through the cow's vaginal mucosa showed that nanoencapsulation promoted I3C controlled release. This way, the developed HG-NC-I3C can be considered a promising approach for trichomoniasis treatment through vaginal administration.

Trichomonas vaginalis Motility Is Blocked by Drug-Free Thermosensitive Hydrogel

Trichomonas vaginalis motility in biological fluids plays a prominent, but understudied, role in parasite infectivity. In this study, the ability of a thermosensitive hydrogel (pluronic F127) to physically immobilize T. vaginalis was investigated. Blocking parasite motility could prevent its attachment to the mucosa, thus reducing the acquisition of the infection. The trajectory of individual parasites was monitored by multiple particle tracking. Mean square displacement, diffusivity, and velocity were calculated from x, y coordinates during time. Major results are that T. vaginalis exhibited different types of trajectories in a diluted solution composed of lactate buffer similar to "run-and-tumble" motion reported for flagellated bacteria. The fastest T. vaginalis specimen moves with a velocity of 19 μm/s. Observation of T. vaginalis movements showed that the cell body remains rigid during swimming and that the propulsive forces necessary to generate the movement are the result of flagellar beating. Parasite motility was partially slowed down using hydroxyethylcellulose hydrogel, used as a reference for the development of vaginal microbicides, while 100% of T. vaginalis were immobile in F127 hydrogel. Once completed by biological investigations on mice, this report suggests using drug-free formulation composed of F127 as a new strategy to prevent T. vaginalis attachment to the mucosa. The concept will be extended to other flagellated organisms where the motility is driven by cilia and flagella.

A journey through the emergence of nanomedicines with poly(alkylcyanoacrylate) based nanoparticles

Starting in the late 1970s, the pioneering work of Patrick Couvreur gave birth to the first biodegradable nanoparticles composed of a biodegradable synthetic polymer. These nanoparticles, made of poly(alkylcyanoacrylate) (PACA), were the first synthetic polymer-based nanoparticulate drug carriers undergoing a phase III clinical trial so far. Analyzing the journey from the birth of PACA nanoparticles to their clinical evaluation, this paper highlights their remarkable adaptability to bypass various drug delivery challenges found on the way. At present, PACA nanoparticles include a wide range of nanoparticles that can associate drugs of different chemical nature and can be administered in vivo by different routes. The most recent technologies giving the nanoparticles customised functions could also be implemented on this family of nanoparticles. Through different examples, this paper discusses the seminal role of the PACA nanoparticles' family in the development of nanomedicines.