Novelin situgelling ocular inserts for voriconazole-loaded niosomes: design,in vitrocharacterisation andin vivoevaluation of the ocular irritation and drug pharmacokinetics

Oleogels for the ocular delivery of epalrestat: formulation, in vitro, in ovo, ex vivo and in vivo evaluation

The ocular administration of lipophilic and labile drugs such as epalrestat, an aldose reductase inhibitor with potential for diabetic retinopathy treatment, demands the development of topical delivery systems capable of providing sufficient ocular bioavailability. The aim of this work was to develop non-aqueous oleogels based on soybean oil and gelators from natural and sustainable sources (ethyl cellulose, beeswax and cocoa butter) and to assess their reproducibility, safety and efficiency in epalrestat release and permeation both ex vivo and in vivo. Binary combinations of gelators at 10% w/w resulted in solid oleogels (oleorods), while single gelator oleogels at 5% w/w remained liquid at room temperature, with most of the oleogels displaying shear thinning behavior. The oleorods released up to 4 µg epalrestat per mg of oleorod in a sustained or burst pattern depending on the gelator (approx. 10% dose in 24 h). The HET-CAM assay indicated that oleogel formulations did not induce ocular irritation and were safe for topical ocular administration. Corneal and scleral ex vivo assays evidenced the permeation of epalrestat from the oleorods up to 4 and 2.5 µg/cm2 after six hours, respectively. Finally, the capacity of the developed oleogels to sustain release and provide significant amounts of epalrestat to the ocular tissues was demonstrated in vivo against aqueous-based niosomes and micelles formulations loaded with the same drug concentration. Overall, the gathered information provides valuable insights into the development of oleogels for ocular drug delivery, emphasizing their safety and controlled release capabilities, which have implications for the treatment of diabetic neuropathy and other ocular conditions.

Ocular Mucoadhesive and Biodegradable Sponge-Like Inserts for the Sustained and Controlled Delivery of Voriconazole; Preparation, D-optimal Factorial Optimization and in-vivo Evaluation

The aim of this study was to formulate and optimize by statistical means mucoadhesive and biodegradable sponge-like inserts loaded with voriconazole (VCZ) which increases the contact time of the drug with the eye and sustain its release from the formula in a controlled manner. This avoids the pulsed effect reported for the drug suspension and results in reducing the number of drug instillations in the eye with the result of enhancing the patient compliance. Also, the sponge like nature of the insert reduces the foreign body sensation caused by other ocular solid dosage forms. They were prepared using casting/freeze-drying technique using five polymers namely high molecular weight chitosan (CH), sodium alginate (AL), sodium carboxy methyl cellulose (CMC), gellan gum (GG) and xanthan gum (XG). The prepared inserts were subjected to evaluations of their visual appearance, weight variation, drug content, surface pH, in-vitro release (percent drug released after 1h (Q1 (%)), mean dissolution time (MDT) and dissolution efficiency (DE)) in addition to kinetic analysis of the release data, water uptake, mucoadhesion and rheology of the forming plain polymer solution at the maximum rate of shear. The independent variables of the D-optimal factorial design were the polymer type and concentration while Q1 (%), MDT, DE, % water uptake after 15 minutes and rheology at the maximum rate of shear were chosen as dependant variables. The performed optimization process using design expert software showed an optimum formula consisting of 2 % GG. It showed slow release behavior compared to the drug suspension. FTIR and DSC studies showed that there is no interaction between VCZ and GG. The optimum formula has good in-vitro mucoadhesive properties and pH in the safe ocular range. Moreover, it showed promising in-vivo results of rapid hydration and gelling in addition to good mucoadhesive behavior when instilled in the eye, high ocular safety and biocompatibility, sustained antifungal activity in comparison to the drug suspension and finally biodegradation. So, it may be taken into consideration as an outstanding carrier for the ocular delivery of VCZ.

Revamping the corneal permeability and antiglaucoma therapeutic potential of brinzolamide using transniosomes: optimization, in vitro and preclinical evaluation

Aim: This study aims to explore potential of transniosomes, a hybrid vesicular system, as ocular drug-delivery vehicle. Materials & methods: Thin-film hydration technique was used to fabricate brinzolamide-loaded transniosomes (BRZ-TN) and optimized using Box-Behnken design, further exhaustively characterized for physicochemical evaluations, deformability, drug release, permeation and preclinical evaluations for antiglaucoma activity. Results: The BRZ-TN showed ultradeformability (deformability index: 5.71), exhibiting sustained drug release without irritation (irritancy score: 0) and high permeability compared with the marketed formulation or free drug suspension. The extensive in vivo investigations affirmed effective targeted delivery of transniosomes, with brinzolamide reducing intraocular pressure potentially. Conclusion: Our findings anticipated that BRZ-TN is a promising therapeutic nanocarrier for effectively delivering cargo to targeted sites by crossing corneal barriers.

Ethanolic Extract Propolis-Loaded Niosomes Diminish Phospholipase B1, Biofilm Formation, and Intracellular Replication of Cryptococcus neoformans in Macrophages

Secretory phospholipase B1 (PLB1) and biofilms act as microbial virulence factors and play an important role in pulmonary cryptococcosis. This study aims to formulate the ethanolic extract of propolis-loaded niosomes (Nio-EEP) and evaluate the biological activities occurring during PLB1 production and biofilm formation of Cryptococcus neoformans. Some physicochemical characterizations of niosomes include a mean diameter of 270 nm in a spherical shape, a zeta-potential of -10.54 ± 1.37 mV, and 88.13 ± 0.01% entrapment efficiency. Nio-EEP can release EEP in a sustained manner and retains consistent physicochemical properties for a month. Nio-EEP has the capability to permeate the cellular membranes of C. neoformans, causing a significant decrease in the mRNA expression level of PLB1. Interestingly, biofilm formation, biofilm thickness, and the expression level of biofilm-related genes (UGD1 and UXS1) were also significantly reduced. Pre-treating with Nio-EEP prior to yeast infection reduced the intracellular replication of C. neoformans in alveolar macrophages by 47%. In conclusion, Nio-EEP mediates as an anti-virulence agent to inhibit PLB1 and biofilm production for preventing fungal colonization on lung epithelial cells and also decreases the intracellular replication of phagocytosed cryptococci. This nano-based EEP delivery might be a potential therapeutic strategy in the prophylaxis and treatment of pulmonary cryptococcosis in the future.

Recent Advances of Ocular Drug Delivery Systems: Prominence of Ocular Implants for Chronic Eye Diseases

Chronic ocular diseases can seriously impact the eyes and could potentially result in blindness or serious vision loss. According to the most recent data from the WHO, there are more than 2 billion visually impaired people in the world. Therefore, it is pivotal to develop more sophisticated, long-acting drug delivery systems/devices to treat chronic eye conditions. This review covers several drug delivery nanocarriers that can control chronic eye disorders non-invasively. However, most of the developed nanocarriers are still in preclinical or clinical stages. Long-acting drug delivery systems, such as inserts and implants, constitute the majority of the clinically used methods for the treatment of chronic eye diseases due to their steady state release, persistent therapeutic activity, and ability to bypass most ocular barriers. However, implants are considered invasive drug delivery technologies, especially those that are nonbiodegradable. Furthermore, in vitro characterization approaches, although useful, are limited in mimicking or truly representing the in vivo environment. This review focuses on long-acting drug delivery systems (LADDS), particularly implantable drug delivery systems (IDDS), their formulation, methods of characterization, and clinical application for the treatment of eye diseases.

Microneedle-based ocular drug delivery systems - recent advances and challenges

Eye diseases and injuries constitute a significant clinical problem worldwide. Safe and effective delivery of drugs to the eye is challenging mostly due to the presence of ocular barriers and clearance mechanisms. In everyday practice, the traditional eye drops, gels and ointments are most often used. Unfortunately, they are usually not well tolerated by patients due to the need for frequent use as well as the discomfort during application. Therefore, novel drug delivery systems with improved biopharmaceutical properties are a subject of ongoing scientific investigations. Due to the developments in microtechnology, in recent years, there has been a remarkable advance in the development of microneedle-based systems as an alternative, non-invasive form for administering drugs to the eye. This review summarizes the latest achievements in the field of obtaining microneedle ocular patches. In the manuscript, the most important manufacturing technologies, microneedle classification, and the research studies related to ophthalmic application of microneedles are presented. Finally, the most important advantages and drawbacks, as well as potential challenges related to the unique anatomy and physiology of the eye are summarized and discussed.

Current Advances in Nano-Based and Polymeric Stimuli-Responsive Drug Delivery Targeting the Ocular Microenvironment: A Review and Envisaged Future Perspectives

Optimal vision remains one of the most essential elements of the sensory system continuously threatened by many ocular pathologies. Various pharmacological agents possess the potential to effectively treat these ophthalmic conditions; however, the use and efficacy of conventional ophthalmic formulations is hindered by ocular anatomical barriers. Recent novel designs of ophthalmic drug delivery systems (DDS) using nanotechnology show promising prospects, and ophthalmic formulations based on nanotechnology are currently being investigated due to their potential to bypass these barriers to ensure successful ocular drug delivery. More recently, stimuli-responsive nano drug carriers have gained more attention based on their great potential to effectively treat and alleviate many ocular diseases. The attraction is based on their biocompatibility and biodegradability, unique secondary conformations, varying functionalities, and, especially, the stimuli-enhanced therapeutic efficacy and reduced side effects. This review introduces the design and fabrication of stimuli-responsive nano drug carriers, including those that are responsive to endogenous stimuli, viz., pH, reduction, reactive oxygen species, adenosine triphosphate, and enzymes or exogenous stimuli such as light, magnetic field or temperature, which are biologically related or applicable in clinical settings. Furthermore, the paper discusses the applications and prospects of these stimuli-responsive nano drug carriers that are capable of overcoming the biological barriers of ocular disease alleviation and/or treatment for in vivo administration. There remains a great need to accelerate the development of stimuli-responsive nano drug carriers for clinical transition and applications in the treatment of ocular diseases and possible extrapolation to other topical applications such as ungual or otic drug delivery.

Cellulosic Polymers for Enhancing Drug Bioavailability in Ocular Drug Delivery Systems

One of the major impediments to drug development is low aqueous solubility and thus poor bioavailability, which leads to insufficient clinical utility. Around 70–80% of drugs in the discovery pipeline are suffering from poor aqueous solubility and poor bioavailability, which is a major challenge when one has to develop an ocular drug delivery system. The outer lipid layer, pre-corneal, dynamic, and static ocular barriers limit drug availability to the targeted ocular tissues. Biopharmaceutical Classification System (BCS) class II drugs with adequate permeability and limited or no aqueous solubility have been extensively studied for various polymer-based solubility enhancement approaches. The hydrophilic nature of cellulosic polymers and their tunable properties make them the polymers of choice in various solubility-enhancement techniques. This review focuses on various cellulose derivatives, specifically, their role, current status and novel modified cellulosic polymers for enhancing the bioavailability of BCS class II drugs in ocular drug delivery systems.

Nanotechnology for Topical Drug Delivery to the Anterior Segment of the Eye

Topical drug delivery is one of the most challenging aspects of eye therapy. Eye drops are the most prevalent drug form, especially for widely distributed anterior segment eye diseases (cataracts, glaucoma, dry eye syndrome, inflammatory diseases, etc.), because they are convenient and easy to apply by patients. However, conventional drug formulations are usually characterized by short retention time in the tear film, insufficient contact with epithelium, fast elimination, and difficulties in overcoming ocular tissue barriers. Not more than 5% of the total drug dose administered in eye drops reaches the interior ocular tissues. To overcome the ocular drug delivery barriers and improve drug bioavailability, various conventional and novel drug delivery systems have been developed. Among these, nanosize carriers are the most attractive. The review is focused on the different drug carriers, such as synthetic and natural polymers, as well as inorganic carriers, with special attention to nanoparticles and nanomicelles. Studies in vitro and in vivo have demonstrated that new formulations could help to improve the bioavailability of the drugs, provide sustained drug release, enhance and prolong their therapeutic action. Promising results were obtained with drug-loaded nanoparticles included in in situ gel.

Statistical optimization of hyaluronic acid enriched ultradeformable elastosomes for ocular delivery of voriconazole via Box-Behnken design: in vitro characterization and in vivo evaluation

Voriconazole (VCZ) is a well-known broad spectrum triazole antifungal, mainly used orally and intravenously. The study aimed to formulate VCZ into ultradeformable elastosomes for the topical treatment of ocular fungal keratitis. Different formulae were prepared using a modified ethanol injection method, employing a 3³ Box-Behnken design. They were characterized by measuring their entrapment efficiency (EE%), particle size (PS), polydispersity index (PDI) and zeta potential (ZP). The optimized formula was subjected to further in vitro investigations and in vivo evaluation studies. The prepared vesicles had satisfactory EE%, PS, PDI and ZP values. The numerical optimization process suggested an optimal elastosomal formula (OE) composed of phosphatidyl choline and brij S100 at the weight ratio of 3.62: 1, 0.25%w/v hyaluronic acid and 5% (percentage from phosphatidyl choline/brij mixture) polyvinyl alcohol. It had high EE (72.6%), acceptable PS and PDI (362.4 nm and 0.25, respectively) and highly negative ZP of −41.7 mV. OE exhibited higher elasticity than conventional liposomes, with acceptable stability for three months. Transmission electron microscopy demonstrated the spherical morphology of vesicles with an external transparent coat of Hyaluronic acid. OE was expected to cause no ocular irritation or blurring in vision as reflected by pH and refractive index measurements. The histopathological study revealed the safety of OE for ocular use. The fungal susceptibility testing using Candida albicans demonstrated the superiority of OE to VCZ suspension, with greater and more durable growth inhibition. Therefore, OE can be regarded as a promising formula, achieving both safety and efficacy.

New bone cements with Pluronic®F127 for prophylaxis and treatment of periprosthetic joint infections

In line with the increase in orthopedic prosthetic surgeries, there has been a significant rise in periprosthetic joint infections (PJI) due to Methicillin-Resistant Staphylococcus Aureus (MRSA) bacteria. In case of infection, antibiotic-added spacers are temporarily placed into the periprosthetic region. With the release of antibiotics usually failing to work in fighting off infection, recent studies have centered around developing more effective approaches. New polymethylmethacrylate (PMMA) cement mixtures were prepared for this study with Pluronic®F127, bicarbonate, and citric acid addition. Optimal solutions were searched by monitoring vancomycin release on consecutive days with HPLC in in-vitro. The strengths of the samples were measured via four-point bending tests. Compared to conventional PMMA, strength values were observed to have improved by about 20% with 1.0 g of Pluronic®F127. According to HPLC studies, the highest increase for the area under the curve value was obtained for Pluronic®F127 doped mixture with a value of about 20%. It is understood from SEM and BET studies that addition of Pluronic®F127 helps increase porosity. The present study concludes that the optimum concentration of Pluronic®F127 could improve the strength and drug-releasing capacity of the spacer by increasing its porosity.

A Review on Ocular Novel Drug Delivery Systems of Antifungal Drugs: Functional Evaluation and Comparison of Conventional and Novel Dosage Forms

Ocular fungal infections affect more than one million people annually worldwide. They can lead to impaired vision or even complete blindness, so they should be treated immediately to prevent such consequences. Although topical administration has always been the most common route of ocular drug delivery owing to high patient acceptance, reduced side effects, and the possibility of self-administration, its limited ocular bioavailability poses a major challenge. As a result, attention has recently been drawn to the design and development of novel drug delivery systems (NDDS) that can overcome the challenges of conventional dosage forms. This research is the first to review and classify the studies which have designed and developed topical ocular NDDS with the aim to compare the performance and antifungal activity of these novel systems with conventional forms. According to the results, all studies seemed to confirm the superiority of NDDS over conventional forms in cases of released and permeated drug and antifungal activity. The NDDS were used specifically to improve ocular delivery by slowing down the release rate, increasing drug permeation, and subsequently increasing the antifungal effects of the active pharmaceutical ingredients. Hence, further studies on NDDS may aid the optimization of ocular drug delivery of antifungal drugs.

Ocular Inserts of Voriconazole-Loaded Proniosomal Gels: Formulation, Evaluation and Microbiological Studies

BACKGROUND

Voriconazole (VRC) is a triazole broad spectrum antifungal drug, used in the management of versatile fungal infections, particularly fungal keratitis. The obligatory use of niosomal delivery of VRC may reduce the frequency of dosing intervals resulting from its short biological half time and consequently improve patient compliance.

METHODS

VRC loaded proniosomes (VRC-PNs) were set by the coacervation technique and completely characterized. The developed formula was comprehensively assessed concerning in- vitro release behavior, kinetic investigation, and its conflict against refrigerated and room temperature conditions. A selected noisomal formula was incorporated into ocusert (VRC-PNs Ocu) formulated by 1% w/w hydroxypropyl methyl cellulose HPMC and 0.1% w/w carbopol 940. Eventually, in vitro antifungal activity against Candida albicans and Aspergillus nidulans was assessed by the cup diffusion method.

RESULTS

The optimized VRC-PNs (Pluronic F127: cholesterol weight ratio 1:1 w/w) exhibited the highest entrapment efficiency (87.4±2.55%) with a spherical shape, proper size in nano range and a suitable Zeta potential of 209.7±8.13 nm and -33.5±1.85 mV, respectively. Assurance of drug encapsulation in nanovesicles was accomplished by several means such as attenuated total reflection Fourier-transform infrared spectroscopy, differential scanning calorimetry in addition to powder X-ray diffraction investigations. It displayed a biphasic in vitro release pattern and after 6 months of storage at a refrigerated temperature, the optimized formula preserved its stability. VRC-PNs Ocu proved a very highly significant antifungal activity matched with the free drug or nanosuspension which was extra assured by comparing its mean inhibition zone with that of 5% natamycin market eye drops.

CONCLUSION

In conclusion, VRC-PNs Ocu could be considered as a promising stable sustained release topical ocular nanoparticulate system for the management of fungal infections.

Emerging potential of niosomes in ocular delivery

INTRODUCTION

Niosomes have recently grabbed attention as one of the best tools for various site-specific drug delivery systems, including ophthalmic drug delivery. Surfactants (nonionic; tweens and spans) of different HLB values and cholesterol are the fundamental components for these formulations. It is an alternative controlled ocular drug delivery system to liposomes to overcome the problems associated with sterilization, large-scale production, and stability. It also enhances the adhesion or retention ability of drug at the ocular site. Hydrophilic or lipophilic or amphoteric drugs can be easily encapsulated in niosomes. Besides, niosomes are a leading vesicular system compatible with most of the drugs for site-specific delivery.

AREAS COVERED

This article reveals challenges and barriers for ocular drug delivery, various transporters and receptors present in the ocular region for the transportation of therapeutics as well as nutrients, and various method of preparations, loading methods and application potential of niosomes in ocular drug delivery.

EXPERT OPINION

Niosomes, a vesicular system offers numerous advantages and applicability because of its good stability, non-immunogenicity, permeation potential, and controlled release ability etc. This drug delivery system has been efficiently used in the treatment of many ocular diseases.

Niosomal Drug Delivery Systems for Ocular Disease-Recent Advances and Future Prospects

The eye is a complex organ consisting of several protective barriers and particular defense mechanisms. Since this organ is exposed to various infections, genetic disorders, and visual impairments it is essential to provide necessary drugs through the appropriate delivery routes and vehicles. The topical route of administration, as the most commonly used approach, maybe inefficient due to low drug bioavailability. New generation safe, effective, and targeted drug delivery systems based on nanocarriers have the capability to circumvent limitations associated with the complex anatomy of the eye. Nanotechnology, through various nanoparticles like niosomes, liposomes, micelles, dendrimers, and different polymeric vesicles play an active role in ophthalmology and ocular drug delivery systems. Niosomes, which are nano-vesicles composed of non-ionic surfactants, are emerging nanocarriers in drug delivery applications due to their solution/storage stability and cost-effectiveness. Additionally, they are biocompatible, biodegradable, flexible in structure, and suitable for loading both hydrophobic and hydrophilic drugs. These characteristics make niosomes promising nanocarriers in the treatment of ocular diseases. Hereby, we review niosome based drug delivery approaches in ophthalmology starting with different preparation methods of niosomes, drug loading/release mechanisms, characterization techniques of niosome nanocarriers and eventually successful applications in the treatment of ocular disorders.

Self-nanoemulsifying drug delivery system to improve transcorneal permeability of voriconazole: in-vivo studies

OBJECTIVE

This study investigates the effectiveness of self-nanoemulsifying drug delivery system (SNEDDS) in improving voriconazole transcorneal permeability.

METHODS

Voriconazole-SNEDDS was prepared with isopropyl myristate, PEG 400, Tween 80^® and Span 80^® and was subjected for physicochemical characterization after reconstitution with NaCl 0.9% (1/9; v/v). In-vitro antifungal activity was assessed and compared with the marketed formulation. In-vivo studies, namely ocular irritation test via modified Draize test and pharmacokinetic study, were investigated using rabbit as animal model.

KEY FINDINGS

Voriconazole-SNEDDS presented a droplet size of 21.353 ± 0.065 nm, a polydispersity index of 0.123 ± 0.003, a pH of 7.205 ± 0.006 and an osmolarity of 342.667 ± 2.517 mOsmol/l after reconstitution with NaCl 0.9%. Voriconazole-SNEDDS minimum inhibitory concentration (MIC₉₀ ) was similar to the one of marketed formulation for Candida species while it was significantly lower (P < 0.001) for Aspergillus fumigatus. Draize test revealed that Voriconazole-SNEDDS was safe for ocular administration. Voriconazole maximum concentration (5.577 ± 0.852 µg/ml) from SNEDDS was higher than marketed formulation (C_max  = 4.307 ± 0.623 µg/ml), and the T_max was delayed to 2 h. The area under the concentration-time curve value of Voriconazole-SNEDDS was improved by 2.419-fold.

CONCLUSION

Our results suggest that SNEDDS is a promising carrier for voriconazole ocular delivery and this encourages further clinical studies.

Amphiphilic copolymers change the nature of the ordered-to-disordered phase transition of lipid membranes from discontinuous to continuous

The phase behaviour as a function of temperature is explored for pure phospholipid (DPPC) and hybrid lipid-polymer (DPPC/Pluronic L64) bilayers with the aid of atomistic MD simulations. The range of the fixed-temperature simulations includes temperatures below and above the known melting temperature (Tm) for DPPC membranes. For the pure lipid bilayer, the main phase transition is discontinuous, as verified by the abrupt changes observed in the membrane structure, elasticity and the lipid diffusivity near the critical temperature Tm, which lies in the region 298.15-303.15 K. A pre-transition step is detected at 298.15 K which has been identified as the ripple phase (Pβ'), where ordered and disordered lipids coexist, causing thickness fluctuations. In the ordered gel phase, the positional ordering as assessed by the lipid radial distribution functions is long-range and some degree of hexagonal packing is measured. The hybrid bilayers on the other hand, transform from a more ordered to a disordered phase in a continuous manner, without finite jumps in their properties. No signs of the ripple phase are identified and the ordered phase exhibits very limited hexagonal packing and some positional ordering that decays fast. The effect of the inserted polymers in the two phases is reversed; at low temperatures, they render the membrane thinner, less cohesive and less ordered compared to the pure one, with the lipids assuming faster diffusion rates, whereas at high temperatures, the polymer interaction with the lipids acts reducing their diffusivity, but also increasing the lipid tail ordering and the membrane stiffness. The ability of the amphiphilic L64 copolymers to change the nature of the main phase transition of lipid membranes and their properties both in the ordered and the disordered phase is of vital importance for the prediction of both the efficacy of hybrid lipid/polymer nanoparticles as drug delivery vehicles as well as their potential adverse implications during interactions with healthy cell membranes.

Research progress of in-situ gelling ophthalmic drug delivery system

Blindness and vision impairment are the most devastating global health problems resulting in a substantial economic and social burden. Delivery of drug to particular parts of the anterior or posterior segment has been a major challenge due to various protective barriers and elimination mechanisms associated with the unique anatomical and physiological nature of the ocular system. Drug administration to the eye by conventional delivery systems results in poor ocular bioavailability (<5%). The designing of a novel approach for a safe, simple, and effective ocular drug delivery is a major concern and requires innovative strategies to combat the problem. Over the past decades, several novel approaches involving different strategies have been developed to improve the ocular delivery system. Among these, the ophthalmic in-situ gel has attained a great attention over the past few years. This review discussed and summarized the recent and the promising research progress of in-situ gelling in ocular drug delivery system.

How the Incorporation of Pluronic Block Copolymers Modulates the Response of Lipid Membranes to Mechanical Stress

We employ atomistic molecular dynamics simulations to investigate the effect that the incorporation of the nonionic amphiphilic copolymer known as Pluronic L64 has on the mechanical stability of a DPPC membrane. The simulations reveal that the incorporation of the polymer chains leads to membranes that can sustain increasing mechanical stresses. Analysis of mechanical, structural, and dynamic properties of the membrane shows that the polymer chains interact strongly with the lipids in the vicinity, restraining their mobility and imparting better mechanical stability to the membrane. The hybrid membranes under tension remain thicker, more ordered, and stiffer in comparison to their lipid analogues. Trans-bilayer lipid movements (flip-flop) are observed and appear to be triggered by the presence of the polymer chains. A careful analysis of the pore formation under high tensions reveals two distinctive mechanisms that depend on the distribution of the hydrophilic polymer blocks in the bilayer. Finally, the rate of growth of the formed membrane defects is slowed down in the presence of polymers. These findings show that Pluronic block copolymers could be exploited for the formation of optimized hybrid nanodevices with controlled elastic and dynamic properties.

Development of antifungal therapies using nanomaterials

The number and diversity of chemical structures currently available as antibacterial drugs is much higher compared with the number of active substances in relation to pathogenic fungi. In this review we focus on nanotechnology approaches, which offer promising strategies to create nanoagents that possess broad-spectrum antifungal activity and might overcome mechanisms of antibiotic resistance. Special attention was given to magnetic nanoparticles and their ability to restrict fungal growth directly, which depends on surface chemistry and pathogen strains. We speculate that future developments of new antifungal methods will take advantage of the current knowledge of using of magnetic nanomaterials as anticancer agents based on their ability to induce hyperthermia and enhance photosensitizing processes.

Voriconazole Composited Polyvinyl Alcohol/Hydroxypropyl-β-Cyclodextrin Nanofibers for Ophthalmic Delivery

Voriconazole (VRC) incorporated in composited polyvinyl alcohol (PVA)/hydroxypropyl-β-cyclodextrin (HPβCD) blended nanofibers were produced via electrospinning for efficient ophthalmic delivery. The VRC loading capacity increased with increasing HPβCD content. The optimal solution for electrospinning consisted of 8% (w/v) PVA, 4% (w/v) HPβCD and 0.5% (w/v) VRC. The nanofibers exhibited bead-free average fiber diameters of 307±31 nm and VRC was released in vitro in a sustained manner. The VRC nanofibers were characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The proton nuclear magnetic resonance (1H-NMR) was used to analyze the molar ratio of HPβCD/VRC in the nanofibers. Compared with a VRC solution, the nanofibers significantly prolonged the half life, and increased the bioavailability of VRC in rabbit tears. No obvious signs of irritation were observed after application in the conjunctival sac. VRC nanofibers are promising for ophthalmic drug delivery and further pharmacodynamics studies are needed.