Nano-precipitated curcumin loaded particles: effect of carrier size and drug complexation with (2-hydroxypropyl)-β-cyclodextrin on their biological performances

Investigating the Effect of Surface Hydrophilicity on the Destiny of PLGA-Poloxamer Nanoparticles in an In Vivo Animal Model

This study aimed to examine the impact of different surface properties of poly(lactic-co-glycolic) acid (PLGA) nanoparticles (P NPs) and PLGA-Poloxamer nanoparticles (PP NPs) on their in vivo biodistribution. For this purpose, NPs were formulated via nanoprecipitation and loaded with diphenylhexatriene (DPH), a fluorescent dye. The obtained NPs underwent comprehensive characterization, encompassing their morphology, technological attributes, DPH release rate, and thermodynamic properties. The produced NPs were then administered to wild-type mice via intraperitoneal injection, and, at scheduled time intervals, the animals were euthanized. Blood samples, as well as the liver, lungs, and kidneys, were extracted for histological examination and biodistribution analysis. The findings of this investigation revealed that the presence of poloxamers led to smaller NP sizes and induced partial crystallinity in the NPs. The biodistribution and histological results from in vivo experiments evidenced that both, P and PP NPs, exhibited comparable concentrations in the bloodstream, while P NPs could not be detected in the other organs examined. Conversely, PP NPs were primarily sequestered by the lungs and, to a lesser extent, by the kidneys. Future research endeavors will focus on investigating the behavior of drug-loaded NPs in pathological animal models.

Characterization of Hyaluronic Acid-Coated PLGA Nanoparticles by Surface-Enhanced Raman Spectroscopy

Nanoparticles (NPs) coated with hyaluronic acid (HA) seem to be increasingly promising for targeted therapy due to HA chemical versatility, which allows them to bind drugs of different natures, and their affinity with the transmembrane receptor CD-44, overexpressed in tumor cells. However, an essential aspect for clinical use of NPs is formulation stability over time. For these reasons, analytical techniques capable of characterizing their physico-chemical properties are needed. In this work, poly(lactide-co-glycolide) (PLGA) NPs with an average diameter of 100-150 nm, coated with a few 10 s of nm of HA, were synthesized. For stability characterization, two complementary investigative techniques were used: Dynamic Light Scattering (DLS) and Surface-Enhanced Raman Scattering (SERS) spectroscopy. The first technique provided information on size, polidispersity index, and zeta-potential, and the second provided a deeper insight on the NP surface chemicals, allowing distinguishing of HA-coated NPs from uncoated ones. Furthermore, in order to estimate formulation stability over time, NPs were measured and monitored for two weeks. SERS results showed a progressive decrease in the signal associated with HA, which, however, is not detectable by the DLS measurements.

A Review of Cyclodextrin Encapsulation and Intelligent Response for the Release of Curcumin

To overcome the low water solubility and low bioavailability of curcumin (CUR), multiple delivery strategies have been proposed. Among these, cyclodextrin-based carriers have been widely used for the encapsulation and delivery of CUR. Cyclodextrins (CDs), as natural oligosaccharides, have been well known for their biodegradability, biocompatibility, non-toxicity, and internal hydrophobic and external hydrophilic structural features. This paper summarizes the recently reported CD-based carriers for encapsulating CUR. Particularly, the polymerization properties of CD self-assembly to enhance the encapsulation of CUR are discussed. In addition, the current progress on stimuli-responsive CD carriers for controlled release of CUR is described, which laid an important foundation for the development of CUR-based precision therapy in clinical practice. In conclusion, this review may provide ideas for the future development of a CD-based encapsulant for CUR.

Complexation of phytochemicals with cyclodextrins and their derivatives- an update

Bioactive phytochemicals from natural source have gained tremendous interest over several decades due to their wide and diverse therapeutic activities playing key role as functional food supplements, pharmaceutical and nutraceutical products. Nevertheless, their application as therapeutically active moieties and formulation into novel drug delivery systems are hindered due to major drawbacks such as poor solubility, bioavailability and dissolution rate and instability contributing to reduction in bioactivity. These drawbacks can be effectively overcome by their complexation with different cyclodextrins. Present article discusses complexation of phytochemicals varying from flavonoids, phenolics, triterpenes, and tropolone with different natural and synthetic cyclodextrins. Moreover, the article summarizes complexation methods, complexation efficiency, stability, stability constants and enhancement in rate and extent of dissolution, bioavailability, solubility, in vivo and in vitro activities of reported complexed phytochemicals. Additionally, the article presents update of published patent details comprising of complexed phytochemicals of therapeutic significance. Thus, phytochemical cyclodextrin complexes have tremendous potential for transformation into drug delivery systems as substantiated by significant outcome of research findings.

Tomato Oil Encapsulation by α-, β-, and γ-Cyclodextrins: A Comparative Study on the Formation of Supramolecular Structures, Antioxidant Activity, and Carotenoid Stability

Cyclodextrins (CDs) are oligosaccharides, comprising 6 (α), 7 (β), or 8 (γ) glucose residues, used to prepare oil-in-water emulsions and improve oil stability towards degradation. In this research, the aptitude of α-, β-, and γ-CDs to form complexes with a supercritical CO₂ extracted lycopene-rich tomato oil (TO) was comparatively assessed. TO/CD emulsions and the resulting freeze-dried powders were characterized by microscopy, Fourier transform infrared-attenuated total reflection (FTIR-ATR), and differential scanning calorimetry (DSC), as well as for their antioxidant activity. Furthermore, carotenoid stability was monitored for 90 days at 25 and 4 °C. Confocal and SEM microscopy revealed morphological differences among samples. α- and β-CDs spontaneously associated into microcrystals assembling in thin spherical shells (cyclodextrinosomes, Ø ≈ 27 µm) at the oil/water interface. Much smaller (Ø ≈ 9 µm) aggregates were occasionally observed with γ-CDs, but most TO droplets appeared "naked". FTIR and DSC spectra indicated that most CDs did not participate in TO complex formation, nevertheless structurally different interfacial complexes were formed. The trolox equivalent antioxidant capacity (TEAC) activity of emulsions and powders highlighted better performances of α- and β-CDs as hydrophobic antioxidants-dispersing agents across aqueous media. Regardless of CDs type, low temperature slowed down carotenoid degradation in all samples, except all-[E]-lycopene, which does not appear efficiently protected by any CD type in the long storage period.

In Vitro and In Vivo Comparison of Curcumin-Encapsulated Chitosan-Coated Poly(lactic-co-glycolic acid) Nanoparticles and Curcumin/Hydroxypropyl-β-Cyclodextrin Inclusion Complexes Administered Intranasally as Therapeutic Strategies for Alzheimer's Disease

Curcumin (CUR) has antioxidant and anti-inflammatory effects that are beneficial to Alzheimer's disease (AD). However, the poor solubility and high instability of CUR compromise its application greatly. In this study, CUR-encapsulated chitosan-coated poly (lactic-co-glycolic acid) nanoparticles (CUR-CS-PLGA-NPs) and hydroxypropyl-β-cyclodextrin-encapsulated CUR complexes (CUR/HP-β-CD inclusion complexes) were developed and compared through intranasal administration. In vitro studies indicated that CUR in CUR/HP-β-CD inclusion complexes was stable under physiological conditions over 72 h with 95.41 ± 0.01% remaining, which was higher than 49.66 ± 3.91% remaining in CUR-CS-PLGA-NPs. Meanwhile, CUR/HP-β-CD inclusion complexes showed a higher cellular uptake level of CUR than CUR-CS-PLGA-NPs in SH-SY5Y cells. Both formulations could reduce CUR's cellular cytotoxicity and showed a comparable antioxidant effect. Both formulations displayed the anti-inflammatory effect at 20 μM CUR in BV-2 cells, which decreased TNF-α and IL-6 levels to approximately 70 and 40%, respectively, when compared to the positive control, respectively. In vivo pharmacokinetic studies indicated that after intranasal administration, the AUC values of CUR in the plasma and brain of the CUR/HP-β-CD inclusion complex group were 2.57-fold and 1.12-fold higher than those in the CUR-CS-PLGA-NP group at the same dose of 2 mg/kg, respectively. In conclusion, CUR/HP-β-CD inclusion complexes displayed better properties than CUR-CS-PLGA-NPs as a carrier for intranasal delivery of CUR for application in AD.

Enhancement of α-Mangostin Wound Healing Ability by Complexation with 2-Hydroxypropyl-β-Cyclodextrin in Hydrogel Formulation

α-Mangostin (α-M), one of the active compounds in Garcinia mangostana peel, has been effectively used in wound healing. However, its poor solubility in aqueous solution causes low bioavailability for skin ulcers, hindering its application in wound healing. The aim of this study was to improve the solubility of α-M through complex formation with 2-hydroxypropyl-β-cyclodextrin (α-M/HP-β-CD CX) and to evaluate the healing activity of the complex. The α-M/HP-β-CD CX was incorporated in a sodium carboxymethylcellulose hydrogel (α-M/HP-β-CD CX HG), and the in vivo healing activity was examined in mice. Evaluation of α-M/HP-β-CD CX HG, including organoleptic evaluation, homogeneity, pH, spreadability, swelling ratio, consistency, scanning electron microscopy (SEM), and in vitro drug release, was carried out. The complex formation of α-M/HP-β-CD CX was confirmed by FTIR and PXRD analysis. The solubility of the α-M/HP-β-CD CX in water linearly increased about 11.7-fold compared to α-M alone, and by 3.5-fold compared to the α-M/HP-β-CD physical mixture (α-M/HP-β-CD CX PM). The α-M/HP-β-CD CX HG was homogenous, the pH was found to be in the neutral range, the spread area was 5 cm, and the consistency was stable until 14 days. SEM analysis showed that α-M/HP-β-CD CX HG surged due to the porous structure of the HG. In addition, in vitro release of α-M from α-M/HP-β-CD CX HG was considerably increased compared to α-M/HP-β-CD PM HG and α-M HG. Notably, in vivo evaluation in mice showed that α-M/HP-β-CD CX HG significantly accelerated the wound healing ability compared to other HGs. Thus, α-M/HP-β-CD CX HG has potential as a new formulation of α-M for wound healing therapy.

Curcumin as an Anticancer Agent in Malignant Mesothelioma: A Review

Malignant mesothelioma is an infrequent tumor that initiates from the mesothelial cells lining of body cavities. The great majority of mesotheliomas originate in the pleural cavity, while the remaining cases initiate in the peritoneal cavity, in the pericardial cavity or on the tunica vaginalis. Usually, mesotheliomas grow in a diffuse pattern and tend to enclose and compress the organs in the various body cavities. Mesothelioma incidence is increasing worldwide and still today, the prognosis is very poor, with a reported median survival of approximately one year from presentation. Thus, the development of alternative and more effective therapies is currently an urgent requirement. The aim of this review article was to describe recent findings about the anti-cancer activity of curcumin and some of its derivatives on mesotheliomas. The potential clinical implications of these findings are discussed.

Skin permeation and thermodynamic features of curcumin-loaded liposomes

This work describes the development of liposomes encapsulating curcumin (CURC) aiming to provide insights on the influence of CURC on the thermodynamic and skin permeation/penetration features of the vesicles. CURC-loaded liposomes were prepared by hydration of lipid film, in the 0.1-15% CURC:DPPC w/w ratio range. The obtained formulations were characterized for their size distribution, zeta potential and vesicle deformability, along with their thermodynamic properties and ex vivo skin penetration/permeation ability. Liposome size was 110-130 nm for all formulations, with fairly narrow size distribution (polydispersity index was ≤0.20) and a zeta potential mildly decreasing with CURC loading. DSC outcomes indicated that CURC interferes with the packing of DPPC acyl chains in liposome bilayer when CURC percentage was at least 10%, leading to a more fluid state than blank and low-payload vesicles. Consistently, the deformability index of liposomes with 15% CURC:DPPC was strongly increased compared to other formulations. This is congruent with ex vivo skin penetration/permeation results, which showed how more deformable liposomes showed an improved deposition in the epidermis, which acts as a reservoir for the active molecule. Altogether, results hint at a possible application of high payload liposomes for improved topical dermal accumulations of actives.

Fabrication of Curcumin-Modified TiO2 Nanoarrays via Cyclodextrin Based Polymer Functional Coatings for Osteosarcoma Therapy

The incomplete removal of bone tumors leads to increased local recurrence and poor prognosis. To prevent ostoperative tumor recurrence and simultaneously repair surgery-caused bone defects, there is a need of great significance to develop implantable biomaterials possessing both cancer cell-killing ability and excellent bioactivity. In this work, a functionalized titanium-based implant is successfully fabricated by loading curcumin (CUR) onto cyclodextrin based polymer (pCD) modified titanium dioxide (TiO₂ ) nanorod arrays. Herein, a polydopamine (pDA) assisted film is implemented as a first coating layer onto the surface of the TiO₂ nanoarrays to guarantee the robust anchorage of the pCD. The pCD coating acts as a reservoir for CUR, allowing for efficient drug loading and sustained release of anticancer drugs. Studies show that the CUR-modified surfaces (TiO₂ /pDA/pCD/CUR) can significantly promote apoptosis of osteosarcoma cells in vitro by inducing mitochondrial dysfunction caused by the ROS overproduction, and meanwhile, effectively inhibit the tumor growth in vivo. Moreover, such functionalized implants with surface density of loaded CUR at 22.48 µg cm^-2 or lower support the attachment and proliferation of osteoblasts in vitro. These results successfully demonstrate that as-prepared TiO₂ /pDA/pCD/CUR constructs have combined anticancer performance and good biocompatibility, which has great promise for the surgical therapy of bone tumors.

Curcumin, Gut Microbiota, and Neuroprotection

Curcumin, a nontoxic, naturally occurring polyphenol, has been recently proposed for the management of neurodegenerative and neurological diseases. However, a discrepancy exists between the well-documented pharmacological activities that curcumin seems to possess in vivo and its poor aqueous solubility, bioavailability, and pharmacokinetic profiles that should limit any therapeutic effect. Thus, it is possible that curcumin could exert direct regulative effects primarily in the gastrointestinal tract, where high concentrations of curcumin are present after oral administration. Indeed, a new working hypothesis that could explain the neuroprotective role of curcumin despite its limited availability is that curcumin acts indirectly on the central nervous system by influencing the “microbiota–gut–brain axis”, a complex bidirectional system in which the microbiome and its composition represent a factor which preserves and determines brain “health”. Interestingly, curcumin and its metabolites might provide benefit by restoring dysbiosis of gut microbiome. Conversely, curcumin is subject to bacterial enzymatic modifications, forming pharmacologically more active metabolites than curcumin. These mutual interactions allow to keep proper individual physiologic functions and play a key role in neuroprotection.

Curcumin C3 complex®/Bioperine® has antineoplastic activity in mesothelioma: an in vitro and in vivo analysis

BACKGROUND

A major limitation in the treatment for malignant mesothelioma is related to serious side effects caused by chemotherapeutics and to the development of cancer-resistance. Advances in cancer therapies have been reached thanks to the introduction of alternative approaches, such as the use of phytochemicals. Curcumin-C3complex®/Bioperine® is a commercially standardized extract containing a ratio-defined mixture of three curcuminoids and piperine that greatly increase its bioavailability. Interestingly, the anticancer effect of this formulation has been described in different studies and several clinical trials have been started, but to our knowledge none refers to human mesothelioma.

METHODS

Curcumin-C3complex®/Bioperine® anticancer effect was evaluated in vitro in different human mesothelioma cell lines analysing cell proliferation, colony-forming assay, wound healing assays, invasion assay and FACS analysis. In vivo anticancer properties were analysed in a mesothelioma xenograft mouse model in CD1 Nude mice.

RESULTS

Curcumin-C3complex®/Bioperine® in vitro induced growth inhibition in all mesothelioma cell lines analysed in a dose- and time-depended manner and reduced self-renewal cell migration and cell invasive ability. Cell death was due to apoptosis. The analysis of the molecular signalling pathway suggested that intrinsic apoptotic pathway is activated by this treatment. This treatment in vivo delayed the growth of the ectopic tumours in a mesothelioma xenograft mouse model.

CONCLUSIONS

Curcumin-C3complex®/Bioperine® treatment strongly reduces in vitro tumorigenic properties of mesothelioma cells by impairing cellular self-renewal ability, proliferative cell rate and cell migration and delays tumor growth in xenograft mouse model by reducing angiogenesis and increasing apoptosis. Considering that curcumin in vivo synergizes drug effects, its administration to treatment regimen may help to enhance drug therapeutic efficacy in mesothelioma. Our results suggest that implementation of standard pharmacological therapies with novel compounds may pave the way to develop alternative approaches to mesothelioma.

Drug micro-carriers with a hyaluronic acid corona toward a diffusion-limited aggregation within the vitreous body

Posterior eye segment diseases are treated through monthly intravitreal injections, that evoke serious side effects. A promising approach to reduce injection frequency consists in producing biodegradable microspheres (MPs) releasing the protein in the vitreous body for long times. Moreover, a rational design of these MPs requires a discouraged diffusion/sedimentation within the intravitreal space, which are detrimental for the vision and the control over drug release kinetics. In this work, poly(lactic-co-glycolic acid) (PLGA)-based MPs encapsulating bovine serum albumin (BSA) were coated with hyaluronic acid (HA) at two molecular weights and tested for their release, diffusion and degradation features in simulated vitreous body (SVB). Results indicate that HA corona prolongs MP degradation time and BSA release. Furthermore, HA coating increased the affinity between MPs and SVB, thereby repressing device transport compared to control PLGA MPs. Results hold promise for the possible application of HA-decorated MPs for intravitreal injection of protein drugs.

Low-dose curcuminoid-loaded in dextran nanobubbles can prevent metastatic spreading in prostate cancer cells

Preventing recurrences and metastasis of prostate cancer after prostatectomy by administering adjuvant therapies is quite a controversial issue. In addition to effectiveness, absence of side effects and long term toxicity are mandatory. Curcuminoids (Curc) extracted with innovative techniques and effectively loaded by polymeric nanobubbles (Curc-NBs) satisfy such requirements. Curc-NBs showed stable over 30 d, were effectively internalized by tumor cells and were able to slowly release Curc in a sustained way. Significant biological effects were detected in PC-3 and DU-145 cell lines where Curc-NBs were able to inhibit adhesion and migration, to promote cell apoptosis and to affect cell viability and colony-forming capacity in a dose-dependent manner. Since the favourable effects are already detectable at very low doses, which can be reached at a clinical level, the actual drug concentration can be visualized and monitored by US or MRI, Curc-NBs can be proposed as an effective adjuvant theranostic tool.

Preparation, Characterization and Antioxidant Evaluation of Poorly Soluble Polyphenol-Loaded Nanoparticles for Cataract Treatment

Cataract, one of the leading causes of blindness worldwide, is a condition in which complete or partial opacity develops in the lens of the eyes, thereby impairing vision. This study aimed to examine the potential therapeutic and protective effects of poorly soluble polyphenols like curcumin, resveratrol, and dibenzoylmethane, known to possess significant antioxidant activity. The polyphenols were loaded into novel lipid-cyclodextrin-based nanoparticles and characterized by particle size, polydispersity index, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy (SEM), entrapment efficiency, and release studies. Ferric-reducing ability of plasma and 2,2-diphenyl-1-picrylhydrazyl chemical assays were used to evaluate their antioxidant properties based on their free radical quenching ability. Biochemical in vitro assays were used to examine these polyphenols on hydrogen peroxide-induced formation of cataracts in bovine lenses by estimating total glutathione content and superoxide dismutase activity. Nanoparticles were thermostable and amorphous. Particle size of curcumin, resveratrol, and dibenzoylmethane nanoparticles were 331.0 ± 17.9 nm, 329.9 ± 1.9 nm, and 163.8 ± 3.2 nm, respectively. SEM confirmed porous morphology and XRD confirmed physical stability. Entrapment efficiency for curcumin-, resveratrol-, and dibenzoylmethane-loaded nanoparticles was calculated to be 84.4 ± 2.4%, 72.2 ± 1.5%, and 86.4 ± 0.6%, respectively. In vitro release studies showed an initial burst release followed by a continuous release of polyphenols from nanoparticles. Chemical assays confirmed the polyphenols' antioxidant activity. Superoxide dismutase and glutathione levels were found to be significantly increased (p < 0.05) after treatment with polyphenol-loaded nanoparticles than pure polyphenols; thus, an improved antioxidant activity translational into potential anticataract activity of the polyphenols when loaded into nanoparticles was observed as compared to pure polyphenols.

Tracking translocation of self-discriminating curcumin hybrid nanocrystals following intravenous delivery

Nanocrystals hold great potential as parenteral delivery carrier systems for poorly water-soluble drugs. Elucidation of the in vivo fate of parenteral nanocrystals is of pharmacological, toxicological and mechanistic significance. However, it is of tremendous difficulty to monitor real-time translocation of nanocrystals in vivo owing to progressive dissolution of nanocrystals and a lack of workable tools to probe nanocrystals. In this study, self-discriminating hybrid nanocrystals (SDHNs) of a model drug curcumin (CUR) were developed by embedding traces of environment-responsive fluorescent dyes into the crystalline lattices of CUR. The SDHNs glow, but the released dyes aggregate and quench spontaneously due to the aggregation-caused quenching (ACQ) effect. Following intravenous administration into rats, a large fraction of CUR nanocrystals are cleared from blood rapidly and accumulate mainly in liver and lung. A small fraction circulate in blood for at least 48 h. Long circulating might be attributable to the surface coating with poloxamer 188, a stabilizer used during preparation; nevertheless, the ultimate fate of nanocrystals ends in reticulo-endothelial organs and tissues. It is implied that parenteral delivery provide sustained release and prolonged pharmacological efficacy, but concomitantly raise concerns of local toxicity in vital organs and tissues, especially when the active ingredients are highly toxic.