Nasal administration of liquid crystal precursor mucoadhesive vehicle as an alternative antiretroviral therapy

Mucoadhesive liquid crystal precursor system for photodynamic therapy of oral cancer mediated by methylene blue

Oral cancer is one of the most prevalent types of cancer head and neck cancers worldwide. Photodynamic therapy (PDT) has demonstrated great potential against cancers, reducing long-term morbidity. In this study, we investigated the incorporation of methylene blue (MB) in a mucoadhesive liquid crystal precursor system (LCPS) for oral cancer treatment. The photostability and the in vitro release, permeation, and retention profile of MB-loaded LCPS (MB-LCPS) were investigated, as well as its in vitro PDT activity against normal (HaCaT) and tumoral (HSC-3) cell lines. LCPS increased the photostability of MB and exhibited a prolonged release profile of MB. In addition, LCPS increased the retention of MB in the porcine esophageal mucosa by around 3 times higher than the MB solution. The retention of MB in LCPS was around 2 times greater than its permeability, which is suitable for guaranteeing the maintenance of the therapy in the oral cavity. In vitro cytotoxicity assay indicated that MB-LCPS increased the antitumoral activity of MB after 20 min of irradiation at 660 nm and 12.5 J/cm2. The results obtained suggest that the developed formulation is an interesting strategy for the potential application in the treatment of oral cancer by PDT.

Intranasal in situ gelling liquid crystal for delivery of resveratrol ameliorates memory and neuroinflammation in Alzheimer's disease

Alzheimer's disease (AD) is an illness that affects people aged 65 or older and affects around 6.5 million in the United States. Resveratrol is a chemical obtained from natural products and it exhibits biological activity based on inhibiting the formation, depolymerization of the amyloid, and decreasing neuroinflammation. Due to the insolubility of this compound; its incorporation in surfactant-based systems was proposed to design an intranasal formulation. A range of systems has been produced by mixing oleic acid, CETETH-20 and water. Polarised light microscopy (PLM), small angle x-ray scattering (SAXS) and transmission electron microscopy (TEM) confirm the initial liquid formulation (F) presented as microemulsion (ME). After dilution, the gelled systems were characterized as hexagonal mesophase and they showed feasibility proprieties. Pharmacological assays performed after intranasal administration showed the ability to improve learning and memory in animals, as well as remission of neuroinflammation via inhibition of interleukin.

Lyotropic liquid crystal mesophases as transdermal delivery systems for lipophilic drugs: A comparative study

The present work aimed to evaluate different Liquid Crystal Mesophases (LCM) as transdermal drug delivery systems (TDDS) for nifedipine (NFD), a lipophilic drug model. The formulations composed of water, Citrus sinensis essential oil (CSEO), PPG-5-CETETH-20, and Olive oil ester PEG-7 were obtained and characterized by polarized light microscopy (PLM), rheology, small-angle x-ray scattering (SAXS), Fourier transform infrared coupled with an attenuated total reflection accessory (FTIR-ATR) and in vitro assays: bioadhesion, drug release, skin permeation, and retention tests. As a result, changes in component proportions led to several transparent viscous systems with an anisotropic profile. PLM and SAXS proved the presence of lamellar (S1), hexagonal (S3), and lamellar + hexagonal (S2) LCM, and rheology showed a high viscoelasticity profile. LCMs were able to adhere to the skin, and S2 achieved higher adhesion strength. NFD (5 mg/mL) has not modified the organization of LCMs. Results also showed that S3 promoted higher permeation and retention and higher disorganization of stratum corneum lipids, which is the main permeation-enhancing mechanism. Thus, the formulations obtained can carry and improve drug delivery through the skin and are promising TDDS for lipophilic drug administration, such as NFD.

Lipidic lyotropic liquid crystals: Insights on biomedical applications

Liquid crystals (LCs) possess unique physicochemical properties, translatable into a wide range of applications. To date, lipidic lyotropic LCs (LLCs) have been extensively explored in drug delivery and imaging owing to the capability to encapsulate and release payloads with different characteristics. The current landscape of lipidic LLCs in biomedical applications is provided in this review. Initially, the main properties, types, methods of fabrication and applications of LCs are showcased. Then, a comprehensive discussion of the main biomedical applications of lipidic LLCs accordingly to the application (drug and biomacromolecule delivery, tissue engineering and molecular imaging) and route of administration is examined. Further discussion of the main limitations and perspectives of lipidic LLCs in biomedical applications are also provided. STATEMENT OF SIGNIFICANCE: Liquid crystals (LCs) are those systems between a solid and liquid state that possess unique morphological and physicochemical properties, translatable into a wide range of biomedical applications. A short description of the properties of LCs, their types and manufacturing procedures is given to serve as a background to the topic. Then, the latest and most innovative research in the field of biomedicine is examined, specifically the areas of drug and biomacromolecule delivery, tissue engineering and molecular imaging. Finally, prospects of LCs in biomedicine are discussed to show future trends and perspectives that might be utilized. This article is an ampliation, improvement and actualization of our previous short forum article "Bringing lipidic lyotropic liquid crystal technology into biomedicine" published in TIPS.

Design and Characterization of Lipid-Surfactant-Based Systems for Enhancing Topical Anti-Inflammatory Activity of Ursolic Acid

Skin inflammation is a symptom of many skin diseases, such as eczema, psoriasis, and dermatitis, which cause rashes, redness, heat, or blistering. The use of natural products with anti-inflammatory properties has gained importance in treating these symptoms. Ursolic acid (UA), a promising natural compound that is used to treat skin diseases, exhibits low aqueous solubility, resulting in poor absorption and low bioavailability. Designing topical formulations focuses on providing adequate delivery via application to the skin surface. The aim of this study was to formulate and characterize lipid-surfactant-based systems for the delivery of UA. Microemulsions and liquid crystalline systems (LCs) were characterized by polarized light microscopy (PLM), rheology techniques, and textural and bioadhesive assays. PLM supported the self-assembly of these systems and elucidated their formation. Rheologic examination revealed pseudoplastic and thixotropic behavior appropriate, and assays confirmed the ability of these formulations to adhere to the skin. In vivo studies were performed, and inflammation induced by croton oil was assessed for response to microemulsions and LCs. UA anti-inflammatory activities of ~60% and 50% were demonstrated by two microemulsions and 40% and 35% by two LCs, respectively. These data support the continued development of colloidal systems to deliver UA to ameliorate skin inflammation.

Mucus adhesion vs. mucus penetration? Screening nanomaterials for nasal inhalation by MD simulation

Nanocarrier-aided drug delivery techniques have improved the absorption and permeability of drugs in nose-to-brain delivery. However, the molecular properties of nanocarriers during the delivery process are of great interest; in particular, the characteristics when penetrating barriers in vivo are crucial for the screening and optimization of materials for nasal inhalation. In this study, we have focused on two types of delivery systems: mucoadhesive nanoparticles (MAPs) and mucopenetrating nanoparticles (MPPs); both have been widely used for mucosal delivery, although a method for selecting the more effective type of drug carriers for mucosal delivery has not been established. Molecular dynamics (MD) simulations were used to reveal the all-atom dynamic characteristics of the interaction between different delivery systems and the nasal mucus protein MUC5AC. Among the systems tested, hydroxypropyltrimethyl ammonium chloride chitosan (HTCC) had the strongest interaction with mucin, suggesting it had better mucoadhesive performance, and that it interacted with MUC5AC more strongly than unmodified chitosan. In contrast, the mucus-penetrating material polyethylene glycol-poly lactic acid-co-glycolic acid (PEG-PLGA), had almost no interaction with MUC5AC. The results of the MD simulations were verified by in vitro experiments on nanoparticles (NPs) and mucin binding. The drug delivery performance of the four types of NPs, analyzed by in vitro and ex vivo mucosal penetration, were all generally consistent with the properties of the material predicted from the MD simulation. These clues to the molecular mechanism of MAPs and MPPs may provide useful insight into the screening and optimization of nanomaterials suitable for nasal inhalation.

Hydroxyethylcellulose-Based Hydrogels Containing Liposomes Functionalized with Cell-Penetrating Peptides for Nasal Delivery of Insulin in the Treatment of Diabetes

Liposomes functionalized with cell-penetrating peptides are a promising strategy to deliver insulin through the nasal route. A hydrogel based on hydroxyethylcellulose (HEC) aqueous solution was prepared, followed by a subsequent addition of liposomes containing insulin solution functionalized with trans-activator of transcription protein of HIV-1 (TAT) or Penetratin (PNT). The formulations were characterized for rheological behavior, mucoadhesion, syringeability, in vitro release and in vivo efficacy. Rheological tests revealed non-Newtonian fluids with pseudoplastic behavior, and the incorporation of liposomes (HLI, HLI_TAT and HLI_PNT) in hydrogels did not alter the behavior original pseudoplastic characteristic of the HEC hydrogel. Pseudoplastic flow behavior is a desirable property for formulations intended for the administration of drugs via the nasal route. The results of syringeability and mucoadhesive strength from HEC hydrogels suggest a viable vehicle for nasal delivery. Comparing the insulin release profile, it is observed that HI was the system that released the greatest amount while the liposomal gel promoted greater drug retention, since the liposomal system provides an extra barrier for the release through the hydrogel. Additionally, it is observed that both peptides tested had an impact on the insulin release profile, promoting a slower release, due to complexation with insulin. The in vitro release kinetics of insulin from all formulations followed Weibull's mathematical model, reaching approximately 90% of release in the formulation prepared with HEC-based hydrogels. Serum insulin levels and the antihyperglycemic effects suggested that formulations HI and HLI have potential as carriers for insulin delivery by the nasal pathway, a profile not observed when insulin was administered by subcutaneous injection or by the nasal route in saline. Furthermore, formulations functionalized with TAT and PNT can be considered promoters of late and early absorption, respectively.

Microemulsions formed by PPG-5-CETETH-20 at low concentrations for transdermal delivery of nifedipine: Structural and in vitro study

Nifedipine is a potent anti-hypertensive, which is poorly orally bioavailable on account of first-pass metabolism, short half-life, and low water solubility. This study aimed to develop a microemulsified system with low surfactant concentration and to evaluate the influence of microemulsion (ME) phase behavior on skin permeation of nifedipine, as drug model. Thereafter, MEs were obtained using PPG-5-CETETH-20, oleic acid, and phosphate buffer at pH 5.0. The selected MEs were isotropic, with droplet diameters less than 10 nm, polydispersity index < 0.25, and pH between 5.0 and 5.2. MEs presented low viscosity and Newtonian behavior. SAXS results confirmed bicontinuous and oil-in-water (o/w) MEs formation. The presence of the drug promoted only very slight modifications in the ME structure. The MEs presented ability to deliver nifedipine via the transdermal route when in comparison with the control. Nevertheless, the skin permeated and retained amounts from the o/w and bicontinuous formulations did not differ significantly. The ATR-FTIR demonstrated that both formulations promoted fluidization and disorganization of lipids and increased the drug diffusion and partition coefficients in the skin. In conclusion, PPG-5-CETETH-20 MEs obtained proved to be effective skin permeation enhancers, acting by rising the coefficients of partition and diffusion of the nifedipine in the skin.

A robust mucin-containing poly(vinyl alcohol) hydrogel model for the in vitro characterization of mucoadhesion of solid dosage forms

Mucoadhesion testing at macroscopic scale needs a robust, convenient in vitro method as ex vivo methods suffer from poor reproducibility and ethical problems. Here we synthesized mucin-free poly(vinyl alcohol) (PVA) and mucin-containing PVA hydrogel substrates (Muc/PVA) to measure adhesion of polymer tablets. Freezing-thawing method was used for gelation to avoid chemical cross-linking and to preserve the functionality of mucin. The adhesion of first generation mucoadhesive polymers, poly(acrylic acid) (PAA) and hydroxypropylmethylcellulose (HPMC) was tested with outstanding reproducibility on individual batches of hydrogels and qualitative agreement with ex vivo literature data. Negatively charged PAA was less adhesive on Muc/PVA surface than on mucin-free PVA whereas HPMC as a neutral polymer displayed similar adhesion strength on both surfaces. Chitosan as a positively charged polymer showed enhanced adhesion on Muc/PVA substrate compared to mucin-free PVA. These results are corroborated by turbidimetric titration which indicated attractive electrostatic interactions between chitosan and mucin in contrast to the lack of attractive interactions for PAA and HPMC. These results prove the role of electronic theory in macroscopic mucoadhesion.

Mucoadhesive, Thermoreversible Hydrogel, Containing Tetracaine-Loaded Nanostructured Lipid Carriers for Topical, Intranasal Needle-Free Anesthesia

Recent advances have been reported for needle-free local anesthesia in maxillary teeth by administering a nasal spray of tetracaine (TTC) and oxymetazoline, without causing pain, fear, and stress. This work aimed to assess whether a TTC-loaded hybrid system could reduce cytotoxicity, promote sustained permeation, and increase the anesthetic efficacy of TTC for safe, effective, painless, and prolonged analgesia of the maxillary teeth in dental procedures. The hybrid system based on TTC (4%) encapsulated in nanostructured lipid carriers (NLC) and incorporated into a thermoreversible hydrogel of poloxamer 407 (TTCNLC-HG4%) displayed desirable rheological, mechanical, and mucoadhesive properties for topical application in the nasal cavity. Compared to control formulations, the use of TTCNLC-HG4% slowed in vitro permeation of the anesthetic across the nasal mucosa, maintained cytotoxicity against neuroblastoma cells, and provided a three-fold increase in analgesia duration, as observed using the tail-flick test in mice. The results obtained here open up perspectives for future clinical evaluation of the thermoreversible hybrid hydrogel, which contains TTC-loaded NLC, with the aim of creating an effective, topical, intranasal, needle-free anesthesia for use in dentistry.

In situ biomimetic lyotropic liquid crystal gel for full-thickness cartilage defect regeneration

There is a great challenge in regenerating cartilage defects, which usually involve absent bearing capacity and poor adaptation to joint movement, further exacerbating subchondral bone damage. Therefore, ideal tissue-engineering cartilage scaffolds should be endowed with biomimetic and sustained-release function for promoting long-term chondrogenesis while protecting subchondral bone. Herein, in situ self-assembling gel based on glyceryl monooleate (GMO)-hyaluronic acid (HA) composite lyotropic liquid crystal (HLC) was developed as the biomimetic scaffold to deliver kartogenin for long-term cartilage regeneration. Compared to the GMO based (LLC) gel, HLC gel with modified lattice structure exhibited improved rheological properties for better joint protection by increasing mechanical strength, elasticity and lubrication. Besides, HLC gel successfully prolonged drug release and retention in the joint cavity over 4 weeks to provide combined effect of kartogenin and HA for cartilage repair. Pharmacodynamic studies demonstrated that HLC gel was the most effective to promote chondrogenesis and protect subchondral bone, making the damaged bone tissue restored to normal in divergent features as evidenced by the MRI, Micro-CT and histological results. Therefore, the HLC gel with joint protection and controlled drug release can serve as a firm scaffold for providing long-term cartilage repair.

Preclinical evaluation of methotrexate-loaded polyelectrolyte complexes and thermosensitive hydrogels as treatment for rheumatoid arthritis

This work proposes new methotrexate (MTX) loaded drug delivery systems (DDS) to treat rheumatoid arthritis via the intra-articular route: a poloxamer based thermosensitive hydrogel (MTX-HG), oligochitosan and hypromellose phthalate-based polyelectrolyte complexes (MTX-PEC) and their association (MTX-PEC-HG). MTX-PEC showed 470 ± 166 nm particle size, 0.298 ± 0.108 polydispersity index, +26 ± 2 mV and 74.3 ± 5.8% MTX efficiency entrapment and particle formation was confirmed by infrared spectroscopy and thermal analysis. MTX-HG and MTX-PEC-HG gelled at 36.7°C. MTX drug release profile was prolonged for MTX-HG and MTX-PEC-HG, and faster for MTX-PEC and free MTX. The in vivo effect of the MTX-DDSs systems was evaluated in induced arthritis rats as single intra-articular dose. The assessed parameters were the mechanical nociceptive threshold, the plasmatic IL-1β level and histological analysis of the tibiofemoral joint. MTX-HG and MTX-PEC-HG performance were similar to free MTX and worse than oral MTX, used as positive control. All DDSs showed some irritative effect, for which further studies are required. MTX-PEC was the best treatment on recovering cartilage damage and decreasing allodynia. Thus, MTX-PEC demonstrated potential to treat rheumatoid arthritis, with the possibility of decreasing the systemic exposure to the drug.

Photodynamic potential of curcumin in bioadhesive formulations: Optical characteristics and antimicrobial effect against biofilms

BACKGROUND

Although Curcumin (CUR) has great potential as a photosensitizer, the low solubility in water impairs its clinical performance in photodynamic inactivation (PDI). This study sought to establish an effective antimicrobial protocol for PDI using CUR in three different bioadhesive formulations.

METHODS

A CUR-loaded chitosan hydrogel with a poloxamer (CUR-CHIH), a CUR-loaded liquid crystal precursor system (CUR-LCP), a CUR-loaded microemulsion (CUR-ME), and CUR in dimethylsulfoxide (DMSO) solution (CUR-S; control formulation) were tested against in vitro and in situ oral biofilms. The optical properties of each formulation were evaluated.

RESULTS

All of the formulations exhibited lower absorbance than CUR-S; however, the CUR-LCP curve bore the highest resemblance. The CUR present in all formulations was completely degraded after 15 min of illumination. In vitro experiments showed that CUR-S was the only formulation able to significantly reduce biofilm viability of Candida albicans and Lactobacillus casei when compared to the negative control (no PDI); the amount of reduction obtained was 1.8 and 3.7 log (CFU/mL) for C. albicans and L. casei, respectively. There was a significant reduction on the viability of Streptococcus mutans biofilms when CUR-S and CUR-LCP were applied (approximately 3.5 and 1.6 log [CFU/mL], respectively). In situ testing showed antimicrobial efficacy against S. mutans and general microorganisms.

CONCLUSIONS

Although the evaluated protocols has not been effective to all of the evaluated microorganisms, PDI showed potential against dental biofilms and evidence that the phototoxic effects of CUR have a high relation with the type of formulation in which it is loaded.

Nanostructural Arrangements and Surface Morphology on Ureasil-Polyether Films Loaded with Dexamethasone Acetate

Ureasil-Poly(ethylene oxide) (ureasil-PEO500) and ureasil-Poly(propylene oxide) (u-PPO400) films, unloaded and loaded with dexamethasone acetate (DMA), have been investigated by carrying out atomic force microscopy (AFM), ultrasonic force microscopy (UFM), contact-angle, and drug release experiments. In addition, X-ray diffraction, small angle X-ray scattering, and infrared spectroscopy have provided essential information to understand the films' structural organization. Our results reveal that while in u-PEO500 DMA occupies sites near the ether oxygen and remains absent from the film surface, in u-PPO400 new crystalline phases are formed when DMA is loaded, which show up as ~30-100 nm in diameter rounded clusters aligned along a well-defined direction, presumably related to the one defined by the characteristic polymer ropes distinguished on the surface of the unloaded u-POP film; occasionally, larger needle-shaped DMA crystals are also observed. UFM reveals that in the unloaded u-PPO matrix the polymer ropes are made up of strands, which in turn consist of aligned ~180 nm in diameter stiffer rounded clusters possibly formed by siloxane-node aggregates; the new crystalline phases may grow in-between the strands when the drug is loaded. The results illustrate the potential of AFM-based procedures, in combination with additional physico-chemical techniques, to picture the nanostructural arrangements in polymer matrices intended for drug delivery.

Nose-to-brain co-delivery of drugs for glioblastoma treatment using nanostructured system

Mutations on the epidermal growth factor receptor (EGFR), induction of angiogenesis, and reprogramming cellular energetics are all biological features acquired by tumor cells during tumor development, and also known as the hallmarks of cancer. Targeted therapies that combine drugs that are capable of acting against such concepts are of great interest, since they can potentially improve the therapeutic efficacy of treatments of complex pathologies, such as glioblastoma (GBM). However, the anatomical location and biological behavior of this neoplasm imposes great challenges for targeted therapies. A novel strategy that combines alpha-cyano-4-hydroxycinnamic acid (CHC) with the monoclonal antibody cetuximab (CTX), both carried onto a nanotechnology-based delivery system, is herein proposed for GBM treatment via nose-to-brain delivery. The biological performance of Poly (D,L-lactic-co-glycolic acid)/chitosan nanoparticles (NP), loaded with CHC, and conjugated with CTX by covalent bonds (conjugated NP) were extensively investigated. The NP platforms were able to control CHC release, indicating that drug release was driven by the Weibull model. An ex vivo study with nasal porcine mucosa demonstrated the capability of these systems to promote CHC and CTX permeation. Blot analysis confirmed that CTX, covalently associated to NP, impairs EGRF activation. The chicken chorioallantoic membrane assay demonstrated a trend of tumor reduction when conjugated NP were employed. Finally, images acquired by fluorescence tomography evidenced that the developed nanoplatform was effective in enabling nose-to-brain transport upon nasal administration. In conclusion, the developed delivery system exhibited suitability as an effective novel co-delivery approaches for GBM treatment upon intranasal administration.

Quality by Design Approach for the Development of Liposome Carrying Ghrelin for Intranasal Administration

The therapeutic use of peptides has increasingly recognized in the development of new therapies. However, the susceptible enzymatic cleavage is a barrier that needs to overcome. Nose-to-brain delivery associated with liposomes can protect peptides against biodegradation and improve the accessibility to brain targets. The aim was to develop a liposomal formulation as ghrelin carrier. The quality by design (QbD) approach was used as a strategy for method development. The initial risk assessments were carried out using a fishbone diagram. A screening design study was performed for the critical material attributes/critical process parameters (CMAs/CPPs) on critical quality attributes (CQAs). Liposomes were obtained by hydrating phospholipid films, followed by extrusion or homogenization, and coated with chitosan. The optimized liposome formulation was produced by high-pressure homogenization coated with chitosan, and the resulted were liposomes size 72.25 ± 1.46 nm, PDI of 0.300 ± 0.027, the zeta potential of 50.3 ± 1.46 mV, and encapsulation efficiency of 53.2%. Moreover, chitosan coating improved performance in ex vivo permeation and mucoadhesion analyzes when compared to the uncoated liposome. In this context, chitosan coating is essential for the performance of the formulations in the ex vivo permeation and mucoadhesion analyzes. The intranasal administration of ghrelin liposomes coated with chitosan offers an innovative opportunity to treat cachexia.

The liquid crystalline phase behaviour of a nasal formulation modifies the brain disposition of donepezil in rats in the treatment of Alzheimer's disease

Although nanoparticles, polymeric micelles, liposomes, nanoemulsions, and microemulsions were extensively evaluated as formulations for nasal administration of drugs, lyotropic liquid crystal (LLC) mesophases have been few studied. The phase transition from a low-viscosity microemulsion to a more viscous LLC may improve the mucoadhesion of the formulation. Donepezil is a drug administered orally in the treatment of Alzheimer's disease, and with gastrointestinal side effects that are typical of acetylcholinesterase inhibitors. Based on this, donepezil administration by nasal pathway using a mucoadhesive LLC may be a feasible alternative. A colloidal formulation was selected from a ternary diagram, combining CETETH-10, oleic acid, and water (40:45:15, w/w). Donepezil was incorporated into the formulation, and the characterisation included in vitro studies, such as mucoadhesion and drug release. Pharmacokinetics in Wistar rats included evaluations by the nasal pathway with donepezil incorporated into microemulsion. A phase transition from an isotropic to an anisotropic system was observed after the swelling of the microemulsion with artificial nasal fluid (12-20 %). The release of donepezil in vitro occurred in a sustained manner. Significant levels of donepezil were achieved in the brain after nasal administration of the microemulsion, as a promising strategy for the treatment of Alzheimer's disease.

Innovative Mucoadhesive Precursor of Liquid Crystalline System Loading Anti-Gellatinolytic Peptide for Topical Treatment of Oral Cancer

Current researches report an actual benefit of a treatment for oral cancer via inhibition of proteolytic matrix metallopro-teinases (MPP) with a peptide drug, called CTT1. However, peptides present poor oral bioavailability. Topical administration on oral mucosa avoids its passage through the gastrointestinal tract and the first-pass liver metabolism, but the barrier function of the oral mucosa can impair the permeation and retention of CTT1. The objective of this study is to incorporate CTT1 into a mucoadhesive precursor of liquid crystalline system (PLCS) as an interesting strategy for the topical treatment of oral cancer. PLCS consisting of oleic acid, ethoxylated 20 and propoxylated cetyl alcohol 5, polyethyleneimine (P)-associated chitosan (C) dispersion and CTT1 (FPC-CTT1) was developed and characterized by polarized light microscopy (PLM) and small-angle X-ray scattering (SAXS). In vitro permeation and retention across esophageal mucosa, In vitro cytotoxicity towards tongue squamous cell carcinoma cells, and in vivo evaluation of vascular changes using the chick embryo chorioallantoic membrane (CAM) model were performed. PLM and SAXS showed that FPC-CTT1acted as PLCS, because it formed a lamellar liquid crystalline system after the addition of artificial saliva. FPC-CTT1increased approximately 2-fold the flux of permeation and 3-fold the retention of CTT1 on the porcine esophageal mucosa. CTT1 does not affect cell viability. CAM tests showed that FPC preserved the blood vessels and it can be a safe formulation. These findings encourage the use of the FPC-CTT1 for topical treatment of oral cancer.

Probiotic nasal spray development by spray drying

The upper respiratory tract (URT) is the main entrance point for many viral and bacterial pathogens, and URT infections are among the most common infections in the world. Recent evidences by our own group and others imply the importance of lactobacilli as gatekeepers of a healthy URT. However, the benefits of putting health-promoting microbes or potential probiotics, such as these URT lactobacilli, in function of URT disease control and prevention is underestimated, among others because of the absence of adequate formulation modalities. Therefore, this study entails important aspects in probiotic nasal spray development with a novel URT-derived probiotic strain by spray drying. We report quantitative and qualitative analysis of several spray-dried formulations, i.e. powders for reconstitution, based on disaccharide or sugar alcohol combinations with a polymer, including their long-term stability. Four formulations with the highest survival of >10⁹ (Colony Forming Units) CFU/g after 28 weeks were further examined upon reconstitution which confirmed sufficiency of one bottle/dosage form during 7 days and rheological properties of shear-thinning. Tests also demonstrated maintained viability and cell morphology overall upon spraying through a nasal spray bottle in all 4 formulations. Lastly, application suitability in terms of high adherence to Calu-3 cells and antimicrobial activity against common URT pathogens was demonstrated and was not impacted neither by powder production process nor by spraying of reconstituted powder through a nasal spray device.

Nanotechnological strategies for systemic microbial infections treatment: A review

Systemic infections is one of the major causes of mortality worldwide, and a shortage of drug approaches applied for the rapid and necessary treatment contribute to increase the levels of death in affected patients. Several drug delivery systems based in nanotechnology such as metallic nanoparticles, liposomes, nanoemulsion, microemulsion, polymeric nanoparticles, solid lipid nanoparticles, dendrimers, hydrogels and liquid crystals can contribute in the biological performance of active substances for the treatment of microbial diseases triggered by fungi, bacteria, virus and parasites. In the presentation of these statements, this review article present and demonstrate the effectiveness of these drug delivery systems for the treatment of systemic diseases caused by several microorganisms, through a review of studies on scientific literature worldwide that contributes to better information for the most diverse professionals from the areas of health sciences. The studies demonstrated that the drug delivery systems described can contribute to the therapeutic scenario of these diseases, being classified as safe, active platforms and with therapeutic versatility.

Nanosystems against candidiasis: a review of studies performed over the last two decades

The crescent number of cases of candidiasis and the increase in the number of infections developed by non-albicans species and by multi-resistant strains has taken the attention of the scientific community, which has been searching for new therapeutic alternatives. Among the alternatives found the use of nanosystems for delivery of drugs already commercialized and new biomolecules have grown, in order to increase stability, solubility, optimize efficiency and reduce adverse effects. In view of the growing number of studies involving technological alternatives for the treatment of candidiasis, the present review came with the intention of gathering studies from the last two decades that used nanotechnology for the treatment of candidiasis, as well as analysing them critically and pointing out the future perspectives for their application with this purpose. Different studies were considered for the development of this review, addressing nanosystems such as metallic nanoparticles, mesoporous silica nanoparticles, polymeric nanoparticles, liposomes, nanoemulsion, microemulsion, solid lipid nanoparticle, nanostructured lipid carrier, lipidic nanocapsules and liquid crystals; and different clinical presentations of candidiasis. As a general overview, nanotechnology has proven to be an important ally for the treatment against the diversity of candidiasis found in the clinic, whether in increasing the effectiveness of commercialized drugs and reducing their adverse effects, as well as allowing exploring more effectively properties therapeutics of new biomolecules.

Modulating chitosan-PLGA nanoparticle properties to design a co-delivery platform for glioblastoma therapy intended for nose-to-brain route

Nose-to-brain delivery is a promising approach to target drugs into the brain, avoiding the blood-brain barrier and other drawbacks related to systemic absorption, and enabling an effective and safer treatment of diseases such as glioblastoma (GBM). Innovative materials and technologies that improve residence time in the nasal cavity and modulate biological interactions represent a great advance in this field. Mucoadhesive nanoparticles (NPs) based on poly(lactic-co-glycolic acid) (PLGA) and oligomeric chitosan (OCS) were designed as a rational strategy and potential platform to co-deliver alpha-cyano-4-hydroxycinnamic acid (CHC) and the monoclonal antibody cetuximab (CTX) into the brain, by nasal administration. The influence of formulation and process variables (O/Aq volume ratio, Pluronic concentration, PLGA concentration, and sonication time) on the properties of CHC-loaded NPs (size, zeta potential, PDI and entrapment efficiency) was investigated by a two-level full factorial design (2⁴). Round, stable nano-sized particles (213-875 nm) with high positive surface charge (+ 33.2 to + 58.9 mV) and entrapment efficiency (75.69 to 93.23%) were produced by the emulsification/evaporation technique. Optimal process conditions were rationally selected based on a set of critical NP attributes (258 nm, + 37 mV, and 88% EE) for further conjugation with CTX. The high cytotoxicity of CHC-loaded NPs and conjugated NPs was evidenced for different glioma cell lines (U251 and SW1088). A chicken chorioallantoic membrane assay highlighted the expressive antiangiogenic activity of CHC-loaded NPs, which was enhanced for conjugated NPs. The findings of this work demonstrated the potential of this nanostructured polymeric platform to become a novel therapeutic alternative for GBM treatment. Graphical abstract.

Nose-to-brain drug delivery mediated by polymeric nanoparticles: influence of PEG surface coating

Intranasal administration of mucus-penetrating nanoparticles is an emerging trend to increase drug delivery to the brain. In order to overcome rapid nasal mucociliary clearance, low epithelial permeation, and local enzymatic degradation, we investigated the influence of PEGylation on nose-to-brain delivery of polycaprolactone (PCL) nanoparticles (PCL-NPs) encapsulating bexarotene, a potential neuroprotective compound. PEGylation with 1, 3, 5, and 10% PCL-PEG did not affect particle diameter or morphology. Upon incubation with artificial nasal mucus, only 5 and 10% of PCL-PEG coating were able to ensure NP stability and homogeneity in mucus. Rapid mucus-penetrating ability was observed for 98.8% of PCL-PEG_5% NPs and for 99.5% of PCL-PEG_10% NPs. Conversely, the motion of non-modified PCL-NPs was markedly slower. Fluorescence microscopy showed that the presence of PEG on NP surface did not reduce their uptake by RMPI 2650 cells. Fluorescence tomography images evidenced higher translocation into the brain for PCL-PEG_5% NPs. Bexarotene loaded into PCL-PEG_5% NPs resulted in area under the curve in the brain (AUC_brain) 3 and 2-fold higher than that for the drug dispersion and for non-PEGylated NPs (p < 0.05), indicating that approximately 4% of the dose was directly delivered to the brain. Combined, these results indicate that PEGylation of PCL-NPs with PCL-PEG_5% is able to reduce NP interactions with the mucus, leading to a more efficient drug delivery to the brain following intranasal administration. Graphical abstract.

Development and Characterization of Nasal Delivery of Selegiline Hydrochloride Loaded Nanolipid Carriers for the Management of Parkinson's Disease

INTRODUCTION

Parkinson's Disease (PD) is one of the most common age-related neurodegenerative disorders which is marked with the loss of dopaminergic neurons. The present study performed on the nose to brain delivery of selegiline hydrochloride loaded nano lipid carrier, suggests that the nasal route is a good mean of targeting the drug directly into the brain.

METHODS AND MATERIALS

Nanostructured lipid carriers were prepared by using hot homogenization. Selegiline hydrochloride loaded NLCs and rotenone treatment were given at a dose of 10 mg/kg administered from 14th day to 28th day. Behavioral parameters were determined at 7th, 14th, 21st and 28th day. On the 28th day, animals were sacrificed for biochemical estimation.

RESULTS

The optimized drug loaded NLC formulation has shown 93±5.25% entrapment efficiency and 51.96% loading capacity. Optimized NLCs formulation has shown 70% release within 10 hours and after that, the release of the drug is sustained up to 22 hours (97%). Pharmacological action of the drug was found to restore the behavioral parameters in rotenone-induced rats.

CONCLUSION

Nano Lipid Carrier (NLCs) therapeutics has emerged as a prominent method for the treatment of Parkinson's Disease (PD) as it offers targeted delivery and enhances the therapeutic efficacy of neurotherapeutics. It is concluded from the studies that, Selegiline HCl loaded nano lipid carrier which was administered through nasal route has the potential to be used in the management therapy of Parkinson's disease.

Mucoadhesive In Situ Gelling Liquid Crystalline Precursor System to Improve the Vaginal Administration of Drugs

The vaginal mucosa is a very promising route for drug administration due to its high permeability and the possibility to bypass first pass metabolism; however, current vaginal dosage forms present low retention times due to their dilution in vaginal fluids, which hampers the efficacy of many pharmacological treatments. In order to overcome these problems, this study proposes to develop a mucoadhesive in situ gelling liquid crystalline precursor system composed of 30% of oleic acid and cholesterol (7:1), 40% of ethoxylated and propoxylated cetyl alcohol, and 30% of a dispersion of 16% Poloxamer 407. The effect of the dilution with simulated vaginal fluid (SVF) on this system was evaluated by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheological studies, texture profile analysis (TPA), mucoadhesion study, in vitro drug release test using hypericin (HYP) as drug model, and cytotoxicity assay. PLM and SAXS confirmed the formation of an isotropic system. After the addition of three different concentrations of SVF (30, 50, and 100%), the resultant formulations presented anisotropy and characteristics of viscous lamellar phases. Rheology shows that formulations with SVF behaved as a non-Newtonian fluid with suitable shear thinning for vaginal application. TPA and mucoadhesion assays indicated the formation of long-range ordered systems as the amount of SVF increases which may assist in the fixation of the formulation on the vaginal mucosa. The formulations were able to control about 75% of the released HYP demonstrating a sustained release profile. Finally, all formulations acted as safe vaginal drug delivery systems.

A Novel Phytantriol-Based Lyotropic Liquid Crystalline Gel for Efficient Ophthalmic Delivery of Pilocarpine Nitrate

The purpose of this paper was to investigate the potential of liquid crystalline (LC) gels for ophthalmic delivery, so as to enhance the bioavailability of pilocarpine nitrate (PN). The gels were prepared by a vortex method using phytantriol and water (in the ratio of 73:27 w/w). Their inner structures were confirmed by crossed polarized light microscopy, small-angle X-ray scattering, attenuated total reflectance-Fourier transform infrared spectrum, and rheology. The in vitro release studies revealed that PN could keep sustained release from the gels over a period of 12 h. The ex vivo apparent permeability coefficient of the gels demonstrated a 3.83-folds (P < 0.05) increase compared with that of eye drops. The corneal hydration levels of the gel maintained in the normal range of 79.46 ± 2.82%, hinting that the gel could be considered non-damaging and safe to the eyes. Furthermore, in vivo residence time evaluation suggested that a better retention performance of LC gel was observed in rabbit's eyes compared to eye drops. In vivo ocular irritation study indicated that LC gel was nonirritant and might be suitable for various eye applications. In conclusion, LC gels might represent a potential ophthalmic delivery strategy to overcome the limitations of eye drops.

A Critical Review of the Properties and Analytical Methods for the Determination of Curcumin in Biological and Pharmaceutical Matrices

Curcumin, a natural compound extracted from turmeric (Curcuma longa), has been extensively studied because of its various pharmacological properties, such as anti-inflammatory, antioxidant, antibiotic, antiprotozoal, immunomodulatory, anti-proliferative, antitumor, and anticarcinogenic effects. However, low solubility in aqueous media has limited its therapeutic applications. To overcome these bioavailability issues, the use of drug delivery systems providing localized or targeted delivery of this drug may represent a more viable therapeutic option. Several drug delivery systems have been shown to significantly enhance the therapeutic efficacy of curcumin. Additionally, a wide variety of analytical methods are available for the qualitative and quantitative analysis of curcumin in different matrices, including plant extracts, biological fluids, and drug delivery systems. There are a variety of methodologies to quantify curcumin, but chromatographic and spectroscopic techniques are the ones most commonly used. Thus, in this review, we evaluate the biological properties of curcumin, as well as its nanotechnology-based delivery systems and methods of analysis.

Curcumin-Loaded Liquid Crystalline Systems for Controlled Drug Release and Improved Treatment of Vulvovaginal Candidiasis

Vulvovaginal candidiasis (VVC) is the most common infection caused by Candida albicans and greatly reduces the quality of life of women affected by it. Due to the ineffectiveness of conventional treatments, there is growing interest in research involving compounds of natural origin. One such compound is curcumin (CUR), which has been proven to be effective against this microorganism. However, some of CUR's physicochemical properties, especially its low aqueous solubility, make the therapeutic application of this compound difficult. Thus, the incorporation of CUR in mucoadhesive liquid crystalline systems (MLCSs) for vaginal administration may be an efficient strategy for the treatment of VVC. MLCSs are capable of potentiating the compound's action, releasing it in a controlled manner, and can enable longer exposure at the site of infection. In this study, MLCSs consisting of oleic acid and ergosterol 5:1 (w/w) as the oily phase, PPG-5-CETETH-20 as the surfactant, and a polymer dispersion of 1% chitosan as the aqueous phase, were developed for the application of CUR (MLCS-CUR) in VVC treatment. The formulations were characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), oscillatory rheometry, continuous shear rheometry, texture profile analysis, and in vitro mucoadhesion. In addition, the antimicrobial activity was evaluated in vitro, and the effects on local fungal burden and cytokine profiles were investigated in a murine model of VVC. PLM and SAXS showed that the developed formulations presented a characteristic of a microemulsion. However, after the addition of artificial vaginal mucus (AVM), PLM showed that the formulations had structures similar to the "Maltese cross" characteristic of lamellar MLCS. Mucoadhesive test results showed an increase in the mucoadhesive strength of these formulations. Rheology analyses suggested long-lasting action of the formulation at the infected site. The in vitro antimicrobial activity assays suggested that CUR possesses antifungal activity against Candida albicans, determined after its incorporation into the MLCS. Further, MLCS-CUR was also more effective in vivo in the control of vaginal infection than treatment with fluconazole. Immunological assays showed that the ratio of pro-inflammatory (IL-1β) to anti-inflammatory (TGF-β) cytokines has decreased and that there is a reduction in the number of polymorphonuclear neutrophils recruited to the vaginal lumen, showing that treatment with MLCS-CUR was effective in modulating the inflammatory reaction associated with the infection. The results suggest that MLCSs could potentially be used in the treatment of VVC with CUR.

Characterization and In Vitro Permeation Study of Cubic Liquid Crystal Containing Sinomenine Hydrochloride

This study developed a new transdermal delivery system for the improved delivery of sinomenine hydrochloride (SH). The delivery system utilized the advantages of lyotropic liquid crystals (LLC) creating an adaptable system that offers a variety of options for the field of transdermal delivery. The formulation was prepared, characterized, and evaluated for its skin penetration in vitro. In the study, the appearance of samples was characterized by visual observation, and these LLC gels were colorless and transparent. Polarizing light microscopy (PLM) and small-angle X-ray diffraction (SAXS) were used to analyze the internal structures of gels, and the gels displayed a cubic double-diamond (P_n3_m) internal structure with a dark field of vision. The Franze diffusion cell was used to evaluate its skin penetration. There were several factors which might influence the skin penetration of drugs, such as drug loading, water content, and the layer spacing of the LLC. In our case, drug concentration gradient played a more powerful role. The result of in vitro permeation studies demonstrated that the drug concentration was higher; the cumulative osmotic quantity of SH (Q) was greater. Therefore, the system was a promising formulation for successful percutaneous delivery of SH through the skin.

Kaempferol-loaded mucoadhesive nanoemulsion for intranasal administration reduces glioma growth in vitro

In order to search for new approaches to treat glioma, intranasal administration has been proposed as an alternative route to deliver drugs into the brain. Among the drug alternatives, kaempferol (KPF) has been reported to induce glioma cell death. This study aimed to prepare nanoemulsions containing KPF with and without chitosan to investigate their potential for brain delivery following intranasal administration, and to evaluate their antitumor activity against glioma cells. KPF-loaded nanoemulsion (KPF-NE) and KPF-loaded mucoadhesive nanoemulsion (KPF-MNE) were prepared by high-pressure homogenization technique and were characterized for their globule size, zeta potential, drug content, pH, viscosity, mucoadhesive strength and morphology. KPF from KPF-MNE showed significantly higher permeation across the mucosa in ex vivo diffusion studies. Histopathological examination suggests both nanoemulsions to be safe for the nasal mucosa and able to preserve KPF antioxidant capability. KPF-MNE enhanced significantly the amount of drug into rat's brain following intranasal administration (5- and 4.5-fold higher than free drug and KPF-NE, respectively). In addition, KPF-MNE reduced C6 glioma cell viability through induction of apoptosis to a greater extent than either free KPF or KPF-NE. The mucoadhesive nanoemulsion developed for intranasal administration may be a promising system for delivery to the brain, and KPF-MNE is a candidate for further antiglioma trials.

Cubic Liquid Crystalline Gels Based on Glycerol Monooleate for Intra-articular Injection

In situ gels containing sinomenine hydrochloride (SMH) for intra-articular (IA) administration to treat rheumatoid arthritis (RA) were designed and investigated in this study. Glycerol monooleate (GMO) was used due to the potential to generate viscous crystalline phase structures upon water absorption. The gels were evaluated using different parameters: syringeability, gelation, viscosity, and drug release. And, polarized light microscopy (PLM), small-angle X-ray scattering investigation (SAXS), and rheological studies were used to analyze their internal structures. In vitro drug release studies were performed by the dialysis membrane diffusion method. The syringeability, viscosity, gelation time, and water for gelation of the obtained preparation met the requirements of IA injection. PLM, SAXS, and rheological analysis showed that all samples had transformed from flowable isotropic solution phases to the inverse cubic (V₂) phases upon excess water. And, the gels were found to be able to maintain the drug release for more than 1 week. Results showed that in situ gels based on GMO liquid crystalline could provide a sustained system for SMH. Due to its sustained release, the in situ cubic gels were suitable for IA injection to treat RA.

Polyethyleneimine and Chitosan Polymer-Based Mucoadhesive Liquid Crystalline Systems Intended for Buccal Drug Delivery

The buccal mucosa is accessible, shows rapid repair, has an excellent blood supply, and shows the absence of the first-pass effect, which makes it a very attractive drug delivery route. However, this route has limitations, mainly due to the continuous secretion of saliva (0.5 to 2 L/day), which may lead to dilution, possible ingestion, and unintentional removal of the active drug. Nanotechnology-based drug delivery systems, such as liquid crystalline systems (LCSs), can increase drug permeation through the mucosa and thereby improve drug delivery. This study aimed at developing and characterizing the mechanical, rheological, and mucoadhesive properties of four liquid crystalline precursor systems (LCPSs) composed of four different aqueous phases (i) water (FW), (ii) chitosan (FC), (iii) polyethyleneimine (FP), or (iv) both polymers (FPC); oleic acid was used as the oil phase, and ethoxylated and propoxylated cetyl alcohol was used as the surfactant. Polarized light microscopy and small-angle X-ray scattering indicated that all LCPSs formed liquid crystalline states after incorporation of saliva. Rheological, texture, and mucoadhesive assays showed that FPC had the most suitable characteristics for buccal application. In vitro release study showed that FPC could act as a controlled drug delivery system. Finally, based on in vitro cytotoxicity data, FPC is a safe buccal drug delivery system for the treatment of several buccal diseases.

Trans-resveratrol-loaded nonionic lamellar liquid-crystalline systems: structural, rheological, mechanical, textural, and bioadhesive characterization and evaluation of in vivo anti-inflammatory activity

Resveratrol (Res) is a common phytoalexin present in a few edible materials, such as grape skin, peanuts, and red wine. Evidence has shown the beneficial effects of Res on human health, which may be attributed to its anti-inflammatory activity. However, the poor aqueous solubility of Res limits its therapeutic effectiveness. Therefore, the use of nanostructured delivery systems for Res, such as liquid-crystalline systems, could be beneficial. In this study, we aimed to develop, characterize, and determine the in vivo effectiveness of Res-loaded liquid-crystalline systems. Systems containing copaiba balsam oil, polyethylene glycol-40 hydrogenated castor oil, and water were designed. Results of polarized light microscopy, small-angle X-ray scattering, texture-profile analysis, and flow-rheology analysis showed that the Res-loaded liquid-crystalline system had a lamellar structure, textural and mechanical (hardness, compressibility, and adhesiveness) properties, and behaved as a non-Newtonian fluid, showing pseudoplastic behavior upon skin application. Furthermore, all liquid-crystalline systems presented bioadhesive properties that may have assisted in maintaining the anti-inflammatory activity of Res, since the topical application of the Res-loaded lamellar mesophase liquid crystals resulted in edema inhibition in a carrageenan-induced paw-inflammation mouse model. Therefore, Res-loaded lamellar mesophases represent a promising new therapeutic approach for inhibition of skin inflammation.

Validation of an HPLC-UV method for analysis of Kaempferol-loaded nanoemulsion and its application to in vitro and in vivo tests

A simple and reliable HPLC-UV method for Kaempferol (KPF) determination in a Kaempferol-loaded nanoemulsion (KPF-NE), samples from mucosa permeation/retention studies, and murine brain was developed and validated according to international guidelines. The analyses were performed on a reversed-phase C18 column at 35°C and under UV detection at 368nm. The mobile phase was composed of methanol:formic acid 0.1% (75:25, v/v) and was eluted at an isocratic flow rate of 1.0mL/min. The method was selective and sensitive for KPF analysis in matrix extracts, and linear in the range of 0.25-7.5μg/mL. The method was also considered precise, accurate, and robust. The recovery rates of KPF from the porcine nasal mucosa and murine brain were higher than 85%. Low matrix effect was observed to determine KPF, including biological matrices. The applicability of the method was confirmed in all different approaches, i.e., quantification of KPF in nanoemulsion, in vitro permeation/retention of KPF across porcine nasal mucosa, and in vivo quantification of KPF in brain samples after nasal administration in rats. Thus, the method is effective and reliable to determine KPF in different real samples. The proposed method, therefore, provides a useful quantification approach to routine processes, to the development of drug delivery systems, and to KPF quantification in different biological matrices. Furthermore, the method is applicable in bioavailability studies and the developed formulation (KPF-NE) is suitable for preclinical trials in different brain disorders.

Development and In Vitro Evaluation of Lyotropic Liquid Crystals for the Controlled Release of Dexamethasone

In this study, amphiphilic polymers were investigated as biomaterials that can control dexamethasone (DXM) release. Such materials present interfacial properties in the presence of water and an oily phase that can result in lyotropic liquid crystalline systems (LLCS). In addition, they can form colloidal nanostructures similar to those in living organisms, such as bilayers and hexagonal and cubic phases, which can be exploited to solubilize lipophilic drugs to sustain their release and enhance bioavailability. It was possible to obtain lamellar and hexagonal phases when combining polyoxyethylene (20) cetyl ether (CETETH-20) polymer with oleic acid (OA), N-methylpyrrolidone (P), isopropyl myristate (IM), and water. The phases were characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheological, textural, and bioadhesion analyses followed by an in vitro release assay. All samples showed elastic behavior in the rheology studies and hexagonal samples containing P and IM showed the highest adhesiveness. The drug release profile of all LLCS presented an average lag time of 3 h and was best fitted to the Korsmeyer-Peppas and Weibull models, with controlled release governed by a combination of diffusion and erosion mechanisms. These systems are potential carriers for DXM and can be explored in several routes of administration, providing potential advantages over conventional pharmaceutical forms.

Spotlight on Biomimetic Systems Based on Lyotropic Liquid Crystal

The behavior of lyotropic biomimetic systems in drug delivery was reviewed. These behaviors are influenced by drug properties, the initial water content, type of lyotropic liquid crystals (LLC), swell ability, drug loading rate, the presence of ions with higher or less kosmotropic or chaotropic force, and the electrostatic interaction between the drug and the lipid bilayers. The in vivo interaction between LCC-drugs, and the impact on the bioavailability of drugs, was reviewed. The LLC with a different architecture can be formed by the self-assembly of lipids in aqueous medium, and can be tuned by the structures and physical properties of the emulsion. These LLC lamellar phase, cubic phase, and hexagonal phase, possess fascinating viscoelastic properties, which make them useful as a dispersion technology, and a highly ordered, thermodynamically stable internal nanostructure, thereby offering the potential as a sustained drug release matrix for drug delivery. In addition, the biodegradable and biocompatible nature of lipids demonstrates a minimum toxicity and thus, they are used for various routes of administration. This review is not intended to provide a comprehensive overview, but focuses on the advantages over non modified conventional materials and LLC biomimetic properties.

Structural Features and the Anti-Inflammatory Effect of Green Tea Extract-Loaded Liquid Crystalline Systems Intended for Skin Delivery

Camellia sinensis, which is obtained from green tea extract (GTE), has been widely used in therapy owing to the antioxidant, chemoprotective, and anti-inflammatory activities of its chemical components. However, GTE is an unstable compound, and may undergo reactions that lead to a reduction or loss of its effectiveness and even its degradation. Hence, an attractive approach to overcome this problem to protect the GTE is its incorporation into liquid crystalline systems (LCS) that are drug delivery nanostructured systems with different rheological properties, since LCS have both fluid liquid and crystalline solid properties. Therefore, the aim of this study was to develop and characterize GTE-loaded LCS composed of polyoxypropylene (5) polyoxyethylene (20) cetyl alcohol, avocado oil, and water (F25E, F29E, and F32E) with different rheological properties and to determine their anti-inflammatory efficacy. Polarized light microscopy revealed that the formulations F25, F29, and F32 showed hexagonal, cubic, and lamellar liquid crystalline mesophases, respectively. Rheological studies showed that F32 is a viscous Newtonian liquid, while F25 and F29 are dilatant and pseudoplastic non-Newtonian fluids, respectively. All GTE-loaded LCS behaved as pseudoplastic with thixotropy; furthermore, the presence of GTE increased the S values and decreased the n values, especially in F29, indicating that this LCS has the most organized structure. Mechanical and bioadhesive properties of GTE-unloaded and -loaded LCS corroborated the rheological data, showing that F29 had the highest mechanical and bioadhesive values. Finally, in vivo inflammation assay revealed that the less elastic and consistent LCS, F25E and F32E presented statistically the same anti-inflammatory activity compared to the positive control, decreasing significantly the paw edema after 4 h; whereas, the most structured and elastic LCS, F29E, strongly limited the potential effects of GTE. Thereby, the development of drug delivery systems with suitable rheological properties may enhance GTE bioavailability, enabling its administration via the skin for the treatment of inflammation.