Surfactant-Free Chitosan/Cellulose Acetate Phthalate Nanoparticles: An Attempt to Solve the Needs of Captopril Administration in Paediatrics.

The Paediatric Committee of the European Medicines Agency encourages research into medicinal products for children, in particular, the development of an age-appropriate formulation of captopril is required in the cardiovascular therapeutic area. The aim of this study was the development of a liquid formulation using nanoparticles based only on chitosan and cellulose acetate phthalate containing captopril for the treatment of hypertension, heart failure and diabetic nephropathy in paediatric patients. Nanoparticles were prepared by a nanoprecipitation method/dropping technique without using surfactants, whose use can be associated with toxicity. A range of different cellulose to chitosan weight ratios were tested. A good encapsulation efficiency (61.0 ± 6.5%) was obtained when a high chitosan concentration was used (1:3 ratio); these nanoparticles (named NP-C) were spherical with a mean diameter of 427.1 ± 32.7 nm, 0.17 ± 0.09 PDI and +53.30 ± 0.95 mV zeta potential. NP-C dispersion remained stable for 28 days in terms of size and drug content and no captopril degradation was observed. NP-C dispersion released 70% of captopril after 2 h in pH 7.4 phosphate buffer and NP-C dispersion did not have a cytotoxicity effect on neonatal human fibroblasts except at the highest dose tested after 48 h. As a result, chitosan/cellulose nanoparticles could be considered a suitable platform for captopril delivery in paediatrics for preparing solid/liquid dosage forms.

Development of a Topical Insulin Polymeric Nanoformulation for Skin Burn Regeneration: An Experimental Approach.

Insulin is a peptide hormone with many physiological functions, besides its use in diabetes treatment. An important role of insulin is related to the wound healing process-however, insulin itself is too sensitive to the external environment requiring the protective of a nanocarrier. Polymer-based nanoparticles can protect, deliver, and retain the protein in the target area. This study aims to produce and characterize a topical treatment for wound healing consisting of insulin-loaded poly-DL-lactide/glycolide (PLGA) nanoparticles. Insulin-loaded nanoparticles present a mean size of approximately 500 nm and neutral surface charge. Spherical shaped nanoparticles are observed by scanning electron microscopy and confirmed by atomic force microscopy. SDS-PAGE and circular dichroism analysis demonstrated that insulin preserved its integrity and secondary structure after the encapsulation process. In vitro release studies suggested a controlled release profile. Safety of the formulation was confirmed using cell lines, and cell viability was concentration and time-dependent. Preliminary safety in vivo assays also revealed promising results.

Development and Mechanistic Insight into the Enhanced Cytotoxic Potential of Parvifloron D Albumin Nanoparticles in EGFR-Overexpressing Pancreatic Cancer Cells.

Pancreatic cancer is one of the most lethal cancers, with an extremely poor prognosis. The development of more effective therapies is thus imperative. Natural origin compounds isolated from Plectranthus genus, such as parvifloron D (PvD), have cytotoxic and antiproliferative activity against human tumour cells. However, PvD is a very low water-soluble compound, being nanotechnology a promising alternative strategy to solve this problem. Therefore, the aim of this study was to optimize a nanosystem for preferential delivery of PvD to pancreatic tumour cells. Albumin nanoparticles (BSA NPs) were produced through a desolvation method. Glucose cross-linking and bioactive functionalization profiles of BSA platform were elucidated and analysed using static lattice atomistic simulations in vacuum. Using the optimized methodology, PvD was encapsulated (yield higher than 80%) while NPs were characterized in terms of size (100-400 nm) and morphology. Importantly, to achieve a preferential targeting to pancreatic cancer cells, erlotinib and cetuximab were attached to the PvD-loaded nanoparticle surface, and their antiproliferative effects were evaluated in BxPC3 and Panc-1 cell lines. Erlotinib conjugated NPs presented the highest antiproliferative effect toward pancreatic tumour cells. Accordingly, cell cycle analysis of the BxPC3 cell line showed marked accumulation of tumour cells in G1-phase and cell cycle arrest promoted by NPs. As a result, erlotinib conjugated PvD-loaded BSA NPs must be considered a suitable and promising carrier to deliver PvD at the tumour site, improving the treatment of pancreatic cancer.

Development of Parvifloron D-loaded Smart Nanoparticles to Target Pancreatic Cancer.

Pancreatic cancer is the eighth leading cause of cancer death worldwide. For this reason, the development of more effective therapies is a major concern for the scientific community. Accordingly, plants belonging to Plectranthus genus and their isolated compounds, such as Parvifloron D, were found to have cytotoxic and antiproliferative activities. However, Parvifloron D is a very low water-soluble compound. Thus, nanotechnology can be a promising delivery system to enhance drug solubility and targeted delivery. The extraction of Parvifloron D from P. ecklonii was optimized through an acetone ultrasound-assisted method and isolated by Flash-Dry Column Chromatography. Then, its antiproliferative effect was selectivity evaluated against different tumor cell lines (IC50 of 0.15 ± 0.05 µM, 11.9 ± 0.7 µM, 21.6 ± 0.5, 34.3 ± 4.1 µM, 35.1 ± 2.2 µM and 32.1 ± 4.3 µM for BxPC3, PANC-1, Ins1-E, MCF-7, HaCat and Caco-2, respectively). To obtain an optimized stable Parvifloron D pharmaceutical dosage form, albumin nanoparticles were produced through a desolvation method (yield of encapsulation of 91.2%) and characterized in terms of size (165 nm; PI 0.11), zeta potential (-7.88 mV) and morphology. In conclusion, Parvifloron D can be efficiently obtained from P. ecklonii and it has shown selective cytotoxicity to pancreatic cell lines. Parvifloron D nanoencapsulation can be considered as a possible efficient alternative approach in the treatment of pancreatic cancer.

Development of a bioadhesive nanoformulation with Glycyrrhiza glabra L. extract against Candida albicans.

Glycyrrhiza glabra L. is considered an important source of bioactive compounds. This study aimed at the development of an efficient solution for the treatment of oral candidiasis. Several extracts of Glycyrrhiza glabra L. were prepared using different solvents and their potential in vitro antifungal activity was assessed. Ethanolic extracts showed the most promising results against C. albicans. This extract was incorporated into mucoadhesive nanoparticles (PLA, PLGA and alginate), which were further included in an oral gel, an oral film and a toothpaste, respectively. The results showed that nanoparticles were successfully produced, presenting a mean size among 100-900 nm with high encapsulation efficiency. In vitro studies showed that the most bioadhesive formulation was the oral film with extract-loaded PLGA nanoparticles, followed by the toothpaste with extract-loaded alginate nanoparticles and the oral gel with extract-loaded PLA nanoparticles.

Broad overview of engineering of functional nanosystems for skin delivery.

Nanotechnology involves the engineering of functional systems at nanoscale and it can be described as a collection of methods and techniques for processing materials to create products with special physicochemical properties. The rapid developments in nanotechnology have allowed the incorporation of therapeutic agents, actives for cosmetic, sensing agents into nanoparticles, for detection, prevention, and treatment of skin diseases. Nanoparticles promote the increase of penetration of drugs and many cosmetic chemicals across the skin. Nanoparticles offer many advantages as carrier systems since they can improve the solubility of poorly water-soluble drugs or actives such as phytocompounds, permeate the skin through different mechanisms, modify drug or actives pharmacokinetic and ultimately, improve their bioavailability. In this review, we discuss the recent advances of different types of nanoparticles for skin delivery over a period of 40 years. This review emphasizes approaches to overcome the drawbacks and limitations associated with the conventional systems and the advances and application that are poised to further enhance the efficacy of topical formulations with nanoparticles, offering the possibility of simplified dosing regimen that may improve treatment outcomes using these novel delivery nanosystems.

Past, Recent Progresses and Future Perspectives of Nanotechnology Applied to Antifungal Agents.

Candida species remain a significant cause of nosocomial bloodstream infections, associated with prolonged hospital stay in the ICU and high healthcare cost. The incidence of Candida is very high in certain risk groups of patients (AIDS, diabetes, cancer, etc.). Recent developments of nanotechnology have strongly contributed to the design of new multifunctional drug carriers that improve drug bioavailability through a controlled and prolonged release profile or even through a more specific targeted delivery of the antifungal agent. Those types of systems have strongly increased with a progressive generation of new structures, permitting the conjunction of new materials, biomolecules, physical and chemical techniques, for better outcomes. Nanotechnology shows expanded possibilities within the medical field and in the case of the yeast infections it may overcome several issues related with the fungal proliferation or higher inhibition of the pathogen causing the infection. This review covers a period of the most representative research of Candidiasis since 1993 to the present.

Pancreatic Cancer Therapy Review: From Classic Therapeutic Agents to Modern Nanotechnologies.

Pancreatic cancer remains one of the most lethal cancers worldwide, with an extremely poor prognosis. This cancer is considered the 5th leading cause of cancer related death. The median survival after diagnosis is generally 2-8 months and five-year survival rate is less than 5%. In recent years, nanotechnology is emerging as a rising approach for drug delivery since it has opened up new landscapes in medicine through introduction of smart nanocarrier systems that can selectively deliver the therapeutic agent in a specific region and in appropriate levels, reducing the adverse side effects. This review covers the main delivery systems developed so far for anticancer drug delivery to the pancreas over a period of 20 years, from polymeric to lipidic-based nanosystems, with a particular emphasis on albumin as core material.

EGF Functionalized Polymer-Coated Gold Nanoparticles Promote EGF Photostability and EGFR Internalization for Photothermal Therapy.

The application of functionalized nanocarriers on photothermal therapy for cancer ablation has wide interest. The success of this application depends on the therapeutic efficiency and biocompatibility of the system, but also on the stability and biorecognition of the conjugated protein. This study aims at investigating the hypothesis that EGF functionalized polymer-coated gold nanoparticles promote EGF photostability and EGFR internalization, making these conjugated particles suitable for photothermal therapy. The conjugated gold nanoparticles (100-200 nm) showed a plasmon absorption band located within the near-infrared range (650-900 nm), optimal for photothermal therapy applications. The effects of temperature, of polymer-coated gold nanoparticles and of UVB light (295nm) on the fluorescence properties of EGF have been investigated with steady-state and time-resolved fluorescence spectroscopy. The fluorescence properties of EGF, including the formation of Trp and Tyr photoproducts, is modulated by temperature and by the intensity of the excitation light. The presence of polymeric-coated gold nanoparticles reduced or even avoided the formation of Trp and Tyr photoproducts when EGF is exposed to UVB light, protecting this way the structure and function of EGF. Cytotoxicity studies of conjugated nanoparticles carried out in normal-like human keratinocytes showed small, concentration dependent decreases in cell viability (0-25%). Moreover, conjugated nanoparticles could activate and induce the internalization of overexpressed Epidermal Growth Factor Receptor in human lung carcinoma cells. In conclusion, the gold nanoparticles conjugated with Epidermal Growth Factor and coated with biopolymers developed in this work, show a potential application for near infrared photothermal therapy, which may efficiently destroy solid tumours, reducing the damage of the healthy tissue.

Functionalized diterpene parvifloron D-loaded hybrid nanoparticles for targeted delivery in melanoma therapy.

AIM: Parvifloron D is a natural diterpene with a broad and not selective cytotoxicity toward human tumor cells. In order to develop a targeted antimelanoma drug delivery platform for Parvifloron D, hybrid nanoparticles were prepared with biopolymers and functionalized with α-melanocyte stimulating hormone. Results/methodology: Nanoparticles were produced according to a solvent displacement method and the physicochemical properties were assessed. It was shown that Parvifloron D is cytotoxic and can induce, both as free and as encapsulated drug, cell death in melanoma cells (human A375 and mouse B16V5). Parvifloron D-loaded nanoparticles showed a high encapsulation efficiency (87%) and a sustained release profile. In vitro experiments showed the nanoparticles' uptake and cell internalization. CONCLUSION: Hybrid nanoparticles appear to be a promising platform for long-term drug release, presenting the desired structure and a robust performance for targeted anticancer therapy.

Bioproduction of gold nanoparticles for photothermal therapy.

BACKGROUND: Photothermal response of plasmonic nanomaterials can be utilized for a number of therapeutic applications such as the ablation of solid tumors. METHODS & RESULTS: Gold nanoparticles were prepared using different methods. After optimization, we applied an aqueous plant extract as the reducing and capping agent of gold and maximized the near-infrared absorption (650-900 nm). Resultant nanoparticles showed good biocompatibility when tested in vitro in human keratinocytes and yeast Saccharomyces cerevisiae. Gold nanoparticles were easily activated by controlled temperature with an ultrasonic water bath and application of a pulsed laser. CONCLUSION: These gold nanoparticles can be synthesized with reproducibility, modified with seemingly limitless chemical functional groups, with adequate controlled optical properties for laser phototherapy of tumors and targeted drug delivery.

Lysozyme Photochemistry as a Function of Temperature. The Protective Effect of Nanoparticles on Lysozyme Photostability.

The presence of aromatic residues and their close spatial proximity to disulphide bridges makes hen egg white lysozyme labile to UV excitation. UVB induced photo-oxidation of tryptophan and tyrosine residues leads to photochemical products, such as, kynurenine, N-formylkynurenine and dityrosine and to the disruption of disulphide bridges in proteins. We here report that lysozyme UV induced photochemistry is modulated by temperature, excitation power, illumination time, excitation wavelength and by the presence of plasmonic quencher surfaces, such as gold, and by the presence of natural fluorescence quenchers, such as hyaluronic acid and oleic acid. We show evidence that the photo-oxidation effects triggered by 295 nm at 20°C are reversible and non-reversible at 10°C, 25°C and 30°C. This paper provides evidence that the 295 nm damage threshold of lysozyme lies between 0.1 µW and 0.3 µW. Protein conformational changes induced by temperature and UV light have been detected upon monitoring changes in the fluorescence emission spectra of lysozyme tryptophan residues and SYPRO® Orange. Lysozyme has been conjugated onto gold nanoparticles, coated with hyaluronic acid and oleic acid (HAOA). Steady state and time resolved fluorescence studies of free and conjugated lysozyme onto HAOA gold nanoparticles reveals that the presence of the polymer decreased the rate of the observed photochemical reactions and induced a preference for short fluorescence decay lifetimes. Size and surface charge of the HAOA gold nanoparticles have been determined by dynamic light scattering and zeta potential measurements. TEM analysis of the particles confirms the presence of a gold core surrounded by a HAOA matrix. We conclude that HAOA gold nanoparticles may efficiently protect lysozyme from the photochemical effects of UVB light and this nanocarrier could be potentially applied to other proteins with clinical relevance. In addition, this study confirms that the temperature plays a critical role in the photochemical pathways a protein enters upon UV excitation.

Polymeric nanoparticles modified with fatty acids encapsulating betamethasone for anti-inflammatory treatment.

Topical glucocorticosteroids were incorporated into nanocarrier-based formulations, to overcome side effects of conventional formulations and to achieve maximum skin deposition. Nanoparticulate carriers have the potential to prolong the anti-inflammatory effect and provide higher local concentration of drugs, offering a better solution for treating dermatological conditions and improving patient compliance. Nanoparticles were formulated with poly-ϵ-caprolactone as the polymeric core along with stearic acid as the fatty acid, for incorporation of betamethasone-21-acetate. Oleic acid was applied as the coating fatty acid. Improvement of the drug efficacy, and reduction in drug degradation with time in the encapsulated form was examined, while administering it locally through controlled release. Nanoparticles were spherical with mean size of 300 nm and negatively charged surface. Encapsulation efficiency was 90%. Physicochemical stability in aqueous media of the empty and loaded nanoparticles was evaluated for six months. Drug degradation was reduced compared to free drug, after encapsulation into nanoparticles, avoiding the potency decline and promoting a controlled drug release over one month. Fourier transform infrared spectroscopy and thermal analysis confirmed drug entrapment, while cytotoxicity studies performed in vitro on human keratinocytes, Saccharomyces cerevisiae models and Artemia salina, showed a dose-response relationship for nanoparticles and free drug. In all models, drug loaded nanoparticles had a greater inhibitory effect. Nanoparticles increased drug permeation into lipid membranes in vitro. Preliminary safety and permeation studies conducted on rats, showed betamethasone-21-acetate in serum after 48 h application of a gel containing nanoparticles. No skin reactions were observed. In conclusion, the developed nanoparticles may be applied as topical treatment, after encapsulation of betamethasone-21-acetate, as nanoparticles promote prolonged drug release, increase drug stability in aqueous media, reducing drug degradation, and increase drug permeability through lipid membranes.

Nimesulide-loaded nanoparticles for the potential coadjuvant treatment of prostate cancer.

Nimesulide (NS)-loaded nanoparticles (NPNS) were prepared from polylactide-co-glycolide (PLGA) and eventually coated with chitosan (NPNSCS). Nanoparticles (NP) were spherical with sizes 379 ± 59 nm for NPNS and 393 ± 66 nm for NPNSCS and zeta potentials of -15 ± 3 mV for NPNS to 10 ± 4 mV for NPNSCS, suggesting an efficient coating. Drug encapsulation rate was high (88 ± 5% and 83 ± 7% of added drug) for NPNS and NPNSCS, respectively. After NP washing and re-suspension, 98 ± 2% and 99 ± 1% of the drug initially entrapped remained associated to NP. NS was dispersed in amorphous state within the polymeric matrix. Two-fold dilution of NP with pH 7.4 PBS provoked no drug release. However, 30-40% NS was released after a 1/10 dilution. NPNSCS and NPNS diluted 1/100 reduced the encapsulated drug to around 30% and 70%, respectively. In contrast, 100% NS was released from NP under sink conditions in less than 2h. The permeability of free-NS (1-1.5 × 10(-5)cm/s) was compared with NPNS (NPNS = 6.4-8.1 × 10(-6)cm/s and NPNSCS = 5.5-7.0 × 10(-6)cm/s) using the PAMPA assay. The cytotoxicity of free-NS and NS in NP on model prostate cancer cells PC-3 and DU-145 showed the highest cytotoxic effect with NPNSCS on PC-3 cells (IC50 = 89 µM).

Preparation and characterization of Δ(9)-tetrahydrocannabinol-loaded biodegradable polymeric microparticles and their antitumoral efficacy on cancer cell lines.

Cannabinoids present an interesting therapeutic potential as antiemetics, appetite stimulants in debilitating diseases (cancer, AIDS and multiple sclerosis), analgesics, and in the treatment of multiple sclerosis and cancer, among other conditions. However, despite their high clinical potential, only few dosage forms are available to date. In this paper, the development of Δ(9)-tetrahydrocannabinol (THC) biodegradable microspheres as an alternative delivery system for cannabinoid parenteral administration is proposed. Tetrahydrocannabinol was encapsulated into biodegradable microspheres by the oil-in-water (o/w) emulsion solvent evaporation method. Several formulations were prepared using different drug:polymer ratios. The influence of antioxidant (α-tocopherol acetate) concentration on the release of THC from the microparticles was studied. Elevated process yield and entrapment efficiencies were achieved. The in vitro drug release studies showed that the encapsulated drug was released over a two week period. As THC has shown therapeutic potential as anticancer drug, the efficacy of the microspheres was tested on different cancer cell lines. Interestingly, the microspheres were able to inhibit cancer cell proliferation during the nine-day study period. All the above results suggest that the use of biodegradable microspheres would be a suitable alternative delivery system for THC administration.

Local delivery of cannabinoid-loaded microparticles inhibits tumor growth in a murine xenograft model of glioblastoma multiforme.

Cannabinoids, the active components of marijuana and their derivatives, are currently investigated due to their potential therapeutic application for the management of many different diseases, including cancer. Specifically, Δ(9)-Tetrahydrocannabinol (THC) and Cannabidiol (CBD) - the two major ingredients of marijuana - have been shown to inhibit tumor growth in a number of animal models of cancer, including glioma. Although there are several pharmaceutical preparations that permit the oral administration of THC or its analogue nabilone or the oromucosal delivery of a THC- and CBD-enriched cannabis extract, the systemic administration of cannabinoids has several limitations in part derived from the high lipophilicity exhibited by these compounds. In this work we analyzed CBD- and THC-loaded poly-ε-caprolactone microparticles as an alternative delivery system for long-term cannabinoid administration in a murine xenograft model of glioma. In vitro characterization of THC- and CBD-loaded microparticles showed that this method of microencapsulation facilitates a sustained release of the two cannabinoids for several days. Local administration of THC-, CBD- or a mixture (1:1 w:w) of THC- and CBD-loaded microparticles every 5 days to mice bearing glioma xenografts reduced tumour growth with the same efficacy than a daily local administration of the equivalent amount of those cannabinoids in solution. Moreover, treatment with cannabinoid-loaded microparticles enhanced apoptosis and decreased cell proliferation and angiogenesis in these tumours. Our findings support that THC- and CBD-loaded microparticles could be used as an alternative method of cannabinoid delivery in anticancer therapies.

Exploiting nanotechnologies and TRPV1 channels to investigate the putative anandamide membrane transporter.

BACKGROUND: Considerable efforts have been made to characterize the pathways regulating the extracellular levels of the endocannabinoid anandamide. However, none of such pathways has been so argued as the existence of a carrier-mediated transport of anandamide across the membrane. Apart from the lack of molecular evidence for such a carrier, the main reasons of this controversy lie in the methodologies currently used to study anandamide cellular uptake. Furthermore, the main evidence in favor of the existence of an "anandamide transporter" relies on synthetic inhibitors of this process, the selectivity of which has been questioned. METHODOLOGY/PRINCIPAL FINDINGS: We used the cytosolic binding site for anandamide on TRPV1 channels as a biosensor to detect anandamide entry into cells, and exploited nanotechnologies to study anandamide membrane transport into intact TRPV1-overexpressing HEK-293 cells. Both fluorescence and digital holographic (DH) quantitative phase microscopy were used to study TRPV1 activation. Poly-epsilon-caprolactone nanoparticles (PCL-NPs) were used to incorporate anandamide, which could thus enter the cell and activate TRPV1 channels bypassing any possible specific protein(s) involved in the uptake process. We reasoned that in the absence of such protein(s), pharmacological tools previously shown to inhibit the "anandamide transporter" would affect in the same way the uptake of anandamide and PCL-NP-anandamide, and hence the activation of TRPV1. However, when masked into PCL-NPs, anandamide cellular uptake became much less sensitive to these agents, although it maintained the same pharmacokinetics and pharmacodynamics as that of "free" anandamide. CONCLUSIONS: We found here that several agents previously reported to inhibit anandamide cellular uptake lose their efficacy when anandamide is prevented from interacting directly with plasma membrane proteins, thus arguing in favor of the specificity of such agents for the putative "anandamide transporter", and of the existence of such mechanism.