Physicochemical, pharmacokinetic, and pharmacodynamic characterization of isradipine tablets for controlled release.

Isradipine is a dihydropyridine calcium channel blocker (CCB) commonly used as vasodilator with antihypertensive properties. A remote-controlled release formulation for isradipine would substantially improve the clinical outcomes of the patients requiring chronic long-term treatment. In this work, sustained release (SR) tablets of isradipine, composed of hydroxypropylmethyl cellulose (HPMC), have been produced by wet granulation and their in vitro and in vivo characterization was compared to a conventional tablet dosage form of immediate release (IR) as preliminary assessment. Tablets composed of 15.0% (wt/wt) HPMC exhibited a SR profile over a period of 24 hours. The release of isradipine followed a Fickian diffusion pattern obeying to the first order kinetics and the extent of absorption was even higher in comparison to the developed conventional tablets, which showed immediate drug release. In vivo studies were carried out in rabbits, showing that the extent of isradipine absorption from the developed tablets was higher in comparison to IR tablets due to the modified release profile obtained for the former (p < 0.05). Our results suggest that SR tablets of isradipine are an efficient solid dosage form to overcome the limitations encountered in conventional IR tablets.

3D printing in the design of pharmaceutical dosage forms.

Three-dimensional (3D) printing technologies are manufacturing approaches with widespread use in industry (e.g. automotive, automobile, pharmaceutical industries). With regard to its use in pharmaceutical industry, 3D printing is demonstrating to be of added value attributed to the possibility of printing tailored pharmaceutical products, namely personalized medical devices, such as implants and other dosage forms. However, with the approval of the first 3D-printed drug-product in 2015, a new perspective has arisen, i.e. the use of this technology to produce solid oral dosage forms exhibiting complex drug release profiles and allowing for individual dosing. Technological hurdles and regulatory issues still have to be overcome before this technology can truly find its place in the healthcare sector, where it can certainly contribute to a personalized and patient-centered healthcare. This manuscript offers a comprehensive analysis of the most extensively used methods of 3D printing in the pharmaceutical field, with examples of solid oral dosage forms and other medical devices currently under development or already marketed.

d-α-tocopherol nanoemulsions: Size properties, rheological behavior, surface tension, osmolarity and cytotoxicity.

The aim of this study was the assessment of the physicochemical stability of d-α-tocopherol formulated in medium chain triglyceride nanoemulsions, stabilized with Tween®80 and Lipoid®S75 as surfactant and co-surfactant, respectively. d-α-tocopherol was selected as active ingredient because of its well-recognized interesting anti-oxidant properties (such as radical scavenger) for food and pharmaceutical industries. A series of nanoemulsions of mean droplet size below 90 nm (polydispersity index < 0.15) have been produced by high-pressure homogenization, and their surface electrical charge (zeta potential), pH, surface tension, osmolarity, and rheological behavior, were characterized as a function of the d-α-tocopherol loading. In vitro studies in Caco-2 cell lines confirmed the safety profile of the developed nanoemulsions with percentage of cell viability above 90% for all formulations.

Compatibility study of paracetamol, chlorpheniramine maleate and phenylephrine hydrochloride in physical mixtures.

Paracetamol (PAR), phenylephrine hydrochloride (PHE) and chlorpheniramine maleate (CPM) are commonly used in clinical practice as antipyretic and analgesic drugs to ameliorate pain and fever in cold and flu conditions. The present work describes the use of thermal analysis for the characterization of the physicochemical compatibility between drugs and excipients during the development of solid dosage forms. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to study the thermal stability of the drug and of the physical mixture (drug/excipients) in solid binary mixtures (1:1). DSC thermograms demonstrated reproducible melting event of the prepared physical mixture. Starch, mannitol, lactose and magnesium stearate influence thermal parameters. Information recorded from the derivative thermogravimetric (DTG) and TGA curves demonstrated the decomposition of drugs in well-defined thermal events, translating the suitability of these techniques for the characterization of the drug/excipients interactions.

Ibuprofen nanocrystals developed by 22 factorial design experiment: A new approach for poorly water-soluble drugs.

The reduction of the particle size of drugs of pharmaceutical interest down to the nano-sized range has dramatically changed their physicochemical properties. The greatest disadvantage of nanocrystals is their inherent instability, due to the risk of crystal growth. Thus, the selection of an appropriate stabilizer is crucial to obtain long-term physicochemically stable nanocrystals. High pressure homogenization has enormous advantages, including the possibility of scaling up, lack of organic solvents and the production of small particles diameter with low polydispersity index. The sequential use of high shear homogenization followed by high pressure homogenization, can modulate nanoparticles' size for different administration routes. The present study focuses on the optimization of the production process of two formulations composed of different surfactants produced by High Shear Homogenization followed by hot High Pressure Homogenization. To build up the surface response charts, a 22 full factorial design experiment, based on 2 independent variables, was used to develop optimized formulations. The effects of the production process on the mean particle size and polydispersity index were evaluated. The best ibuprofen nanocrystal formulations were obtained using 0.20% Tween 80 and 1.20% PVP K30 (F1) and 0.20% Tween 80 and 1.20% Span 80 (F2). The estimation of the long-term stability of the aqueous suspensions of ibuprofen nanocrystals was studied using the LUMISizer. The calculated instability index suggests that F1 was more stable when stored at 4 °C and 22 °C, whereas F2 was shown to be more stable when freshly prepared.

Validation of an UV spectrophotometric assay for the quantification of polymyxin B in solid lipid nanoparticles.

Polymyxins are efficient antibiotic drugs used for the treatment of Gram-negative bacterial infections. These compounds are not absorbed in the gastrointestinal tract and are responsible for serious toxicological effects. In order to enhance their therapeutic effectiveness, decrease the adverse/toxic side effects and promote a sustained release profile, a derivative--polymyxin B sulphate--has been formulated in solid lipid nanoparticles (SLNs) intended for buccal administration. To quantify polymyxin B in the formulation, UV spectrophotometry analysis was applied, validating the analytical methodology by assessing the selectivity, accuracy, precision, linearity, and repeatability. Analyses were performed at 210 nm keeping the samples at 25 degrees C. Results showed that lipid composition of SLNs did not interfere with the polymyxin B spectra. The linearity showed a correlation coefficient of 0.9977 in the range of 5-90 µg/mL. Quantification of polymyxin B by UV spectrophotometry, at 210 nm in SLN formulations, was approved in all analyzed parameters, validating the methodology proposed in this work.

Novel nanostructured lipid carriers loading Apigenin for anterior segment ocular pathologies.

Dry eye disease (DED) is a chronic multifactorial disorder of the ocular surface caused by tear film dysfunction and constitutes one of the most common ocular conditions worldwide. However, its treatment remains unsatisfactory. While artificial tears are commonly used to moisturize the ocular surface, they do not address the underlying causes of DED. Apigenin (APG) is a natural product with anti-inflammatory properties, but its low solubility and bioavailability limit its efficacy. Therefore, a novel formulation of APG loaded into biodegradable and biocompatible nanoparticles (APG-NLC) was developed to overcome the restricted APG stability, improve its therapeutic efficacy, and prolong its retention time on the ocular surface by extending its release. APG-NLC optimization, characterization, biopharmaceutical properties and therapeutic efficacy were evaluated. The optimized APG-NLC exhibited an average particle size below 200 nm, a positive surface charge, and an encapsulation efficiency over 99 %. APG-NLC exhibited sustained release of APG, and stability studies demonstrated that the formulation retained its integrity for over 25 months. In vitro and in vivo ocular tolerance studies indicated that APG-NLC did not cause any irritation, rendering them suitable for ocular topical administration. Furthermore, APG-NLC showed non-toxicity in an epithelial corneal cell line and exhibited fast cell internalization. Therapeutic benefits were demonstrated using an in vivo model of DED, where APG-NLC effectively reversed DED by reducing ocular surface cellular damage and increasing tear volume. Anti-inflammatory assays in vivo also showcased its potential to treat and prevent ocular inflammation, particularly relevant in DED patients. Hence, APG-NLC represent a promising system for the treatment and prevention of DED and its associated inflammation.

Solid dosage forms for active antiretroviral therapy (HAART): dissolution profile study of nevirapine by experimental factorial design.

Nevirapine is the first antiretroviral member of non-nucleoside reverse transcriptase inhibitor used in active antiretroviral therapy (HAART). The aim of this work was the evaluation of the dissolution profile of nevirapine tablets by means of the Disk Intrinsic Dissolution Rate (DIDR) using a 2(3) factorial design. This study used a triplicate in central point and was based on three independent variables: the rotational speed of the apparatus, the compression force of nevirapine disk, and the distance of the tank dissolution. The dependent variable was set as intrinsic dissolution speed (IDS). IDS was strongly dependent on the rotational speed, compression force, and distance of the apparatus, analyzed by Student's t test with 95% confidence, and confirmed by ANOVA. The rotational speed of nevirapine disks was the main factor contributing to the IDS, whereas the compression force and the distance of disks on the dissolution apparatus revealed no effects.

A novel lipid nanocarrier for insulin delivery: production, characterization and toxicity testing.

A novel nanocarrier based on solid lipid nanoparticles (SLNs) was developed for insulin delivery using a novel double emulsion method. Physical stability of particles was assessed by size analysis using dynamic light scattering (DLS), matrix crystallinity by differential scanning calorimetry (DSC) and toxicity analysis by Drosophila melanogaster testing. Insulin-SLNs were composed of Softisan®100 1.25% wt, Lutrol®F68 1% wt, soybean lecithin 0.125% wt, and loaded with 0.73-0.58 mg/mL peptide. Placebo-SLNs (insulin-free) also contained 0.025% wt Tween®80. Mean particle sizes of placebo-SLN and insulin-SLN were 958 ± 9.5 and 978 ± 8.3 nm, respectively. The polydispersity index (PI) was 0.28 ± 0.018 and 0.29 ± 0.013, respectively. Polarized light microscopy analysis depicted no aggregation of developed particles. DSC analysis allowed characterizing SLN with 43-51% matrix crystallinity. Using Drosophila melanogaster test, no toxicity was reported for SLN and for the bulk lipid. This study shows that SLNs are promising and helpful to overcome conventional insulin therapy, in particular for their lack of toxicity for oral delivery.

Optimizing flurbiprofen-loaded NLC by central composite factorial design for ocular delivery.

The purpose of this study was to design and optimize a new topical delivery system for ocular administration of flurbiprofen (FB), based on lipid nanoparticles. These particles, called nanostructured lipid carriers (NLC), were composed of a fatty acid (stearic acid (SA)) as the solid lipid and a mixture of Miglyol(®) 812 and castor oil (CO) as the liquid lipids, prepared by the hot high pressure homogenization method. After selecting the critical variables influencing the physicochemical characteristics of the NLC (the liquid lipid (i.e. oil) concentration with respect to the total lipid (cOil/L (wt%)), the surfactant and the flurbiprofen concentration, on particle size, polydispersity index and encapsulation efficiency), a three-factor five-level central rotatable composite design was employed to plan and perform the experiments. Morphological examination, crystallinity and stability studies were also performed to accomplish the optimization study. The results showed that increasing cOil/L (wt%) was followed by an enhanced tendency to produce smaller particles, but the liquid to solid lipid proportion should not exceed 30 wt% due to destabilization problems. Therefore, a 70:30 ratio of SA to oil (miglyol + CO) was selected to develop an optimal NLC formulation. The smaller particles obtained when increasing surfactant concentration led to the selection of 3.2 wt% of Tween(®) 80 (non-ionic surfactant). The positive effect of the increase in FB concentration on the encapsulation efficiency (EE) and its total solubilization in the lipid matrix led to the selection of 0.25 wt% of FB in the formulation. The optimal NLC showed an appropriate average size for ophthalmic administration (228.3 nm) with a narrow size distribution (0.156), negatively charged surface (-33.3 mV) and high EE (∼90%). The in vitro experiments proved that sustained release FB was achieved using NLC as drug carriers. Optimal NLC formulation did not show toxicity on ocular tissues.

Physicochemical properties of lipid nanoparticles: effect of lipid and surfactant composition.

Understanding the effect of lipid and surfactant composition on particle size and colloidal stability plays a pivotal role in designing lipid nanoparticles (LN) for drug delivery. With respect to our long-term goal, LN for brain delivery, formulations containing lipids and surfactants suitable for intravenous (i.v.) application were selected for the current formulation screening study. LN were prepared by hot high pressure homogenization (HPH) and were characterized during 1 year in terms of macroscopic appearance, particle size by photon correlation spectroscopy (PCS) and optical single particle sizing (OSPS), zeta potential (ZP), as well as physical state and polymorphism by differential scanning calorimetry (DSC). The LN dispersions showed a wide variability in macroscopic appearance, mean size and colloidal stability. Influence factors were the type and concentration of both, the lipid and surfactant component used. The most promising LN showed a small mean size (< 200 nm), a low polydispersity index (PI), (< 0.25) absence of particles in the several-micron range, and a slightly negative ZP (> -12 mV); DSC revealed that some represented supercooled liquids; such LN may be stable at room temperature for at least 1 year. The obtained results are regarded helpful for defining the design space for LN delivery systems, i.e., identifying possible designs and design parameters within the given HPH technology to be applied during future formulation development studies.

Lipid nanoemulsions for anti-cancer drug therapy.

Multifunctional lipid nanoemulsions have shown to combine several advantages e.g. tissue targeting, cell targeting, imaging analysis, barrier permeability enhancement, and therapeutic purposes. Depending on the choice of lipid composition, surfactants and additional surface modifiers ratio, different drug loadings may be achieved and exploited for drug delivery in cancer chemotherapy. However, a safe and effective delivery system for cancer therapy should also be able to overcome the major impediment of multidrug resistance. Several strategies have been tested in nanoemulsions including P-glycoprotein-mediated drug resistance. The present review focuses on a comprehensive discussion of the use of nanoemulsions in anti-cancer therapy, reporting the technological aspects of pharmaceutical formulation of these carriers, and exploiting their advantages in siRNA therapy.

Nanoparticulate carriers (NPC) for oral pharmaceutics and nutraceutics.

The introduction of nanoparticulate carriers (NPC) in the pharmaceutic and nutraceutic fields has changed the definitions of disease management and treatment, diagnosis, as well as the supply food chain in the agri-food sector. NPC composed of synthetic polymers, proteins or polysaccharides gather interesting properties to be used for oral administration of pharmaceutics and nutraceutics. Oral administration remains the most convenient way of delivering drugs (e.g. peptides, proteins and nucleic acids) since these suffer similar metabolic pathways as food supply. Recent advances in biotechnology have produced highly potent new molecules however with low oral bioavailability. A suitable and promising approach to overcome their sensitivity to chemical and enzymatic hydrolysis as well as the poor cellular uptake, would be their entrapment within suitable gastrointestinal (GI) resistant NPC. Increasing attention has been paid to the potential use of NPC for peptides, proteins, antioxidants (carotenoids, omega fatty acids, coenzyme Q10), vitamins, probiotics, for oral administration. This review focuses on the most important materials to produce NPC for oral administration, and the most recent achievements in the production techniques and bioactives successfully delivered by these means.

Dual-drugs delivery in solid lipid nanoparticles for the treatment of Candida albicans mycosis.

Nowadays, a combinatorial drug delivery system that simultaneously transports two or more drugs to the targeted site in a human body, also recognized as a dual-drugs delivery system, represents a promising strategy to overcome drug resistance. Solid lipid nanoparticles loaded with clotrimazole (CLZ) and alphalipolic acid (ALA), considered as an effective agent in the reduction of reactive oxygen species, can enhance anti-infective immunity being proposed as a non-toxic and mainly non-allergic dual-drugs delivery system. In this study, uncoated and cationic CLZ-ALA-loaded SLN were prepared and compared. Suspensions with a narrow size distribution of particles of mean size below 150 nm were obtained, having slight negative or highly positive zeta potential values, due to the presence of the cationic lipid, which also increased nanoparticles stability, as confirmed by Turbiscan® results. Calorimetric studies confirmed the rationale of separately delivering the two drugs in a dual-delivery system. Furthermore, they confirmed the formation of SLN, without significant variation in presence of the cationic lipid. In vitro release studies showed a prolonged drug release without the occurrence of any burst effect. In vitro studies performed on 25 strains of Candida albicans showed the antimicrobial drug activity was not altered when it was loaded into lipid nanoparticles. The study has proved the successfully encapsulation of CLZ and ALA in solid lipid nanoparticles that may represent a promising strategy to combine ALA protective effect in the treatment with CLZ.

Formulating octyl methoxycinnamate in hybrid lipid-silica nanoparticles: An innovative approach for UV skin protection.

Sunscreens have been employed on daily skin care for centuries. Their role in protecting the skin from sun damage, avoiding accelerated photoaging and even limiting the risk of development of skin cancer is unquestionable. Although several chemical and physical filters are approved as sunscreens for human use, their safety profile is dependent on their concentration in the formulation which governs their acceptance by the regulatory agencies. A strategic delivery of such molecules should provide a UV protection and limit the skin penetration. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) may offer an alternative approach to achieve a synergistic effect on the UV protection when loaded with sunscreens as particles themselves also have a UV light scattering effect. Besides, the lipid character of SLN and NLC improves the encapsulation of lipophilic compounds, with enhanced loading capacity. Silica nanoparticles have also been employed in sunscreen formulations. Due to the formed sol-gel complexes, which covalently entrap sunscreen molecules, a controlled release is also achieved. In the present work, we have developed a new sunscreen formulation composed of hybrid SLN-Silica particles loaded with octyl methoxycinnamate (Parsol®MCX), and their further incorporation into a hydrogel for skin administration. Hybrid SLN-silica particles of 210.0 ± 3.341 nm of mean size, polydispersity below 0.3, zeta potential of ca. |7| mV, loading capacity of 19.9% and encapsulation efficiency of 98.3% have been produced. Despite the slight negative surface charge, the developed hybrid nanoparticles remained physicochemically stable over the study period. Turbiscan transmission profiles confirmed the colloidal stability of the formulations under stress conditions. The texture profile analysis of Parsol-SLN and Parsol-SLN-Si revealed semi-solid properties (e.g. adhesiveness, hardness, cohesiveness, springiness, gumminess, chewiness, resilience) suitable for topical application, together with the bioadhesiveness in the skin of pig ears. The non-irritation profile of the hybrid nanoparticles before and after dispersion into Carbopol hydrogels was confirmed by HET-CAM test.

Synthesis, structure-activity relationship and biological evaluation of tetracationic gemini Dabco-surfactants for transdermal liposomal formulations.

In this study, we report the relationship between structure, self-assembly behavior and antimicrobial activity of multicationic gemini surfactants and their successful use as stabilizers of a new liposomal formulation for transdermal drug delivery. New surfactants containing natural moiety 1,4-diazabicyclo[2.2.2]octane with four charges and two hydrophobic chains (n-Dabco-s-Dabco-n, where s = 2, 6, 12 and n = 12, 14, 16, 18) were synthesized. A linear dependence of the CMC decrease, with the increase of the number of carbon atoms in alkyl groups (slope 0.23) was shown. The aggregation numbers of n-Dabco-2-Dabco-n are smaller than 30 and they decrease with increasing alkyl chain length. This is in compliance with the larger surface area per n-Dabco-2-Dabco-n molecule. New liposomal formulations loading Rhodamine B phosphatidylcholine (with mean size about 100 nm and increased zeta potential from -7 ± 2 mV to +55 ± 2 mV) have been successfully stabilized by n-Dabco-s-Dabco-n surfactants. These formulations were designed to improve the bioavailability and skin permeation of loaded compound. The antibacterial activity of Dabco-surfactants was shown to be strongly affected by their structure (alkyl chain length and number of charged nitrogen). 12-Dabco-2-Dabco-12 was the most active (MIC = 0.48, 0.98 and 15.6 µg/mL against S. aureus, B. cereus and E. coli, respectively) without hemolytic activity at 3.1 µg/mL concentration. PC/14-Dabco-2-Dabco-14-liposomes were shown to be the best formulation, with the highest antibacterial activity against Sa (MIC = 7.8 µg‧mL-1) and lowest cytotoxicity (IC50 > 125). The modification of liposomes by Dabco-surfactants stabilizes the membrane of the vesicles, preventing the release of rhodamine B and impairing the penetration of the dye across Strat-M® membrane. Cellular uptake of rhodamine B-loaded PC/12-Dabco-2-Dabco-12-liposomes was also reported. This is the first example of cationic mixed liposomes containing Dabco-surfactants of potential interest for transdermal drug delivery.

Double membrane based on lidocaine-coated polymyxin-alginate nanoparticles for wound healing: In vitro characterization and in vivo tissue repair.

The aim of this study was to develop and characterize a double layer biomembrane for dual drug delivery to be used for the treatment of wounds. The membrane was composed of chitosan, hydroxypropyl methylcellulose and lidocaine chloride (anesthetic drug) in the first layer, and of sodium alginate-polymyxin B sulphate (antibiotic) nanoparticles as the second layer. A product with excellent thickness (0.01-0.02 mm), adequate mechanical properties with respect to elasticity, stiffness, tension, and compatible pH for lesion application has been successfully obtained. The incorporation of the drugs was confirmed analysing the membrane cross-sections by scanning electron microscopy. A strong interaction between the drugs and the functional groups of respective polymers was confirmed by Fourier-Transform Infrared Spectroscopy, thermal analysis and X-ray diffraction. Microbiological assays showed a high antimicrobial activity when polymyxin B was present to act against the Staphylococcus aureus and Pseudomonas aeruginosa strains. Low cytotoxicity observed in a cell viability colorimetric assay and SEM analysis suggest biocompatibility between the developed biomembrane and the cell culture. The in vivo assay allowed visualizing the healing potential by calculating the wound retraction index and by histological analysis. Our results confirm the effectiveness of the developed innovative biomaterial for tissue repair and regeneration in an animal model.

Silver Nanoparticles-Composing Alginate/Gelatine Hydrogel Improves Wound Healing In Vivo.

Polymer hydrogels have been suggested as dressing materials for the treatment of cutaneous wounds and tissue revitalization. In this work, we report the development of a hydrogel composed of natural polymers (sodium alginate and gelatin) and silver nanoparticles (AgNPs) with recognized antimicrobial activity for healing cutaneous lesions. For the development of the hydrogel, different ratios of sodium alginate and gelatin have been tested, while different concentrations of AgNO3 precursor (1.0, 2.0, and 4.0 mM) were assayed for the production of AgNPs. The obtained AgNPs exhibited a characteristic peak between 430-450 nm in the ultraviolet-visible (UV-Vis) spectrum suggesting a spheroidal form, which was confirmed by Transmission Electron Microscopy (TEM). Fourier Transform Infra-red (FT-IR) analysis suggested the formation of strong intermolecular interactions as hydrogen bonds and electrostatic attractions between polymers, showing bands at 2920, 2852, 1500, and 1640 cm-1. Significant bactericidal activity was observed for the hydrogel, with a Minimum Inhibitory Concentration (MIC) of 0.50 µg/mL against Pseudomonas aeruginosa and 53.0 µg/mL against Staphylococcus aureus. AgNPs were shown to be non-cytotoxic against fibroblast cells. The in vivo studies in female Wister rats confirmed the capacity of the AgNP-loaded hydrogels to reduce the wound size compared to uncoated injuries promoting histological changes in the healing tissue over the time course of wound healing, as in earlier development and maturation of granulation tissue. The developed hydrogel with AgNPs has healing potential for clinical applications.

Minoxidil-loaded nanostructured lipid carriers (NLC): characterization and rheological behaviour of topical formulations.

Lipid nanoparticles are used as biocompatible carriers for several types of drugs intended for pharmaceutical, cosmetic, and biochemical purposes. The wide range of lipids and surfactants available for the production of such particles turns these carriers highly suitable for distinct applications (topical, dermal and transdermal, parenteral, pulmonary, and oral administration). This work describes the development of a special type of lipid particles, namely nanostructured lipid carriers (NLC), for minoxidil as an alternative to conventional topical alcoholic solutions. NLC were composed of stearic acid and oleic acid, being the matrix stabilized with poloxamer 188 in aqueous dispersion. To develop a suitable topical formulation, lipid dispersions were further mixed with freshly prepared Carbopol or perfluorocarbon based hydrogels. Minoxidil-loaded NLC were approximately 250 nm in size before the entrapment within the gel network and remained below 500 nm after mixing with both types of hydrogels. The occurrence of minoxidil crystallization in the aqueous phase of lipid dispersions was discarded under analysis by light microscopy and by scanning electron microscopy. Differential scanning calorimetry was used to assess the recrystallization index (i.e. measure of the percentage of lipid matrix that is crystallized) of the particles, which was shown to be 62% for minoxidil-free dispersions and 68% for minoxidil-loaded NLC dispersions. Rheological analysis of hydrogels containing NLC dispersions showed typical pseudoplastic behaviour which makes them suitable for topical purposes.

Uveal melanoma: physiopathology and new in situ-specific therapies.

Uveal melanoma is the most common primary intraocular tumor in adults. It can arise from melanocytes in the anterior (iris) or posterior uveal tract (choroid and ciliary body). Uveal melanoma has a particular molecular pathogenesis, being characterized by specific chromosome alterations and gene mutations (e.g., GNAQ/GNA11; BAP1), which are considered promising targets for molecular therapy. Primary treatment of uveal melanoma includes radiotherapy (brachytherapy and charged-particle therapy), phototherapy (photocoagulation, transpupillary thermal therapy, and photodynamic therapy) and surgery (local resection, enucleation and exenteration). Approximately half of patients with uveal melanoma will, however, develop metastasis, especially in the liver. The treatment of metastatic uveal melanoma includes systemic chemotherapy, immunotherapy and molecular targeted therapy. Liver-directed therapies, such as resection, chemoembolization, immunoembolization, radioembolization, isolated hepatic perfusion and percutaneous hepatic perfusion, are also available to treat metastatic uveal melanoma. Several clinical trials are being developed to study new therapeutic options to treat uveal melanoma, mainly for those with identified liver metastases. The present work discusses the physiopathology and new in situ-specific therapies for the treatment of uveal melanoma.