Tendon Tissue Repair in Prospective of Drug Delivery, Regenerative Medicines, and Innovative Bioscaffolds.

The natural healing capacity of the tendon tissue is limited due to the hypovascular and cellular nature of this tissue. So far, several conventional approaches have been tested for tendon repair to accelerate the healing process, but all these approaches have their own advantages and limitations. Regenerative medicine and tissue engineering are interdisciplinary fields that aspire to develop novel medical devices, innovative bioscaffold, and nanomedicine, by combining different cell sources, biodegradable materials, immune modulators, and nanoparticles for tendon tissue repair. Different studies supported the idea that bioscaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potentiality. However, available data are lacking to allow definitive conclusion on the use of bioscaffolds for tendon regeneration and repairing. In this review, we provide an overview of the current basic understanding and material science in the field of bioscaffolds, nanomedicine, and tissue engineering for tendon repair.

Conventional Nanosized Drug Delivery Systems for Cancer Applications.

Clinical responses and tolerability of conventional nanocarriers (NCs) are sometimes different from those expected in anticancer therapy. Thus, new smart drug delivery systems (DDSs) with stimuli-responsive properties and novel materials have been developed. Several clinical trials demonstrated that these DDSs have better clinical therapeutic efficacy in the treatment of many cancers than free drugs. Composition of DDSs and their surface properties increase the specific targeting of therapeutics versus cancer cells, without affecting healthy tissues, and thus limiting their toxicity versus unspecific tissues. Herein, an extensive revision of literature on NCs used as DDSs for cancer applications has been performed using the available bibliographic databases.

Targeting of the Pilosebaceous Follicle by Liquid Crystal Nanocarriers: In Vitro and In Vivo Effects of the Entrapped Minoxidil.

The topical administration of active compounds represents an advantageous strategy to reach the various skin components as well as its appendages. Pilosebaceous follicles are skin appendages originating in the deeper skin layers. They are very difficult to target, and hence higher active dosages are generally required to achieve effective biological responses, thus favoring the rise of side effects. The aim of this work was to design a supramolecular colloidal carrier, i.e., a liquid crystal nanocarrier, for the selective delivery of active compounds into the pilosebaceous follicle. This nanocarrier showed mean sizes of ~80 nm, a good stability, a negative surface charge, and great safety properties. In vitro studies highlighted its ability to contain and release different substances and to successfully permeate the skin. Minoxidil was encapsulated in the nanocarriers and the in vivo biological effect was compared with a conventional dosage form. Minoxidil-loaded liquid crystal nanocarrier was able to selectively reach the pilosebaceous follicle, thus allowing an increased biological effectiveness of the delivered active in terms of biological response, duration of the biological effects, and reduction of collaterals. Our investigation showed that liquid crystal nanocarriers represent a promising device for the treatment of different pilosebaceous follicular impairments/diseases.

Diameters and Fluorescence Calibration for Extracellular Vesicle Analyses by Flow Cytometry.

Extracellular vesicles (EVs) play a crucial role in the intercellular crosstalk. Mesenchymal stem cell-derived EVs (MSC-EVs), displaying promising therapeutic roles, contribute to the strong rationale for developing EVs as an alternative therapeutic option. EV analysis still represents one of the major issues to be solved in order to translate the use of MSC-EV detection in clinical settings. Even if flow cytometry (FC) has been largely applied for EV studies, the lack of consensus on protocols for FC detection of EVs generated controversy. Standard FC procedures, based on scatter measurements, only allows the detection of the "tip of the iceberg" of all EVs. We applied an alternative FC approach based on the use of a trigger threshold on a fluorescence channel. The EV numbers obtained by the application of the fluorescence triggering resulted significantly higher in respect to them obtained from the same samples acquired by placing the threshold on the side scatter (SSC) channel. The analysis of EV concentrations carried out by three different standardized flow cytometers allowed us to achieve a high level of reproducibility (CV < 20%). By applying the here-reported method highly reproducible results in terms of EV analysis and concentration measurements were obtained.

Ammonium glycyrrhizate skin delivery from ultradeformable liposomes: A novel use as an anti-inflammatory agent in topical drug delivery.

Glycyrrhiza glabra L. is a native plant of Central and South-Western Asia that is also diffused in the Mediterranean area and contains several bioactive compounds such as: flavonoids, sterols, triterpene and saponins. Glycyrrhizin, containing glycyrrhizic and glycyrrhizinic acids has anti-inflammatory and antiallergic effects that are similar to corticosteroids. Ammonium glycyrrhizinate is a derivative salt of glycyrrhizic acid with similar anti-inflammatory activity that cannot pass through the skin due to its physicochemical properties and molecular weight. Although several nanoformulations, such as ethosomes, are designed to provide a systemic effect through a topical application, there are different limitations to the distribution inside the blood stream. For this reason, ultradeformable liposomes, or transfersomes, are selected to improve the topical delivery of drugs and allow the distribution of payloads in the blood stream because they pass intact through the stratum corneum epidermis barrier, due to the presence of sodium cholate, aqueous cutaneous gradient, and the rapid penetration of transfersomes by cutaneous tight junctions, thus allowing the systemic delivery of different therapeutic cargo in non-occlusive conditions. The aim of this work was the synthesis and physicochemical characterization of the ammonium glycyrrhizinate-loaded ultradeformable liposomes, the evaluation of drug release and permeation through stratum corneum and epidermis barrier. The in vivo anti-inflammatory effect of ammonium glycyrrhizinate-loaded ultradeformable liposomes was tested on human healthy volunteers. The results demonstrated that the ammonium glycyrrhizinate-loaded ultradeformable liposomes decreased the skin inflammation on the human volunteers and the resulting nanoformulations can be used as a potential topical drug delivery system for anti-inflammatory therapy. ☆Parts of these results were presented as a poster communication at the Recent Developments in Pharmaceutical Analysis 2019 (RDPA 2019), Chieti, Italy.

Design, synthesis and characterization of a PEGylated stanozolol for potential therapeutic applications.

Stanozolol (STZ) is a drug used to treat serious disorders like aplastic anemia and hereditary angioedema. It is also indicated as an adjunct therapy for the treatment of vascular disorders and growth failures. Encouraging results obtained using animal models demonstrated that STZ increases bone formation and mineralization, thus improving both density and biomechanical properties. Like natural androgens, such as TST and 5α-dihydrotestosterone (5α-DHT), STZ binds androgen receptor (AR) to activate AR-mediated signaling. Despite its therapeutic effects, this synthetic anabolic-androgenic steroid (AAS), or 5α-DHT derivative, due to its high lipophilicity, is poor soluble in water. Thus, to increase the water solubility and stability of STZ, as well as its bioavailability and efficacy, an innovative PEGylated STZ (STZ conjugated with (MeO-PEG-NH2)10kDa, (MeO-PEG-NH)10kDa-STZ) was synthesized. As confirmed by chromatography (RP-HPLC) and spectrometry (ATR-FTIR, 1H NMR, elemental CHNS(O) analysis, MALDI-TOF/TOF) analyses, a very pure, stable and soluble compound was obtained. Acetylcholinesterase (AChE) competitive ELISA demonstrated that the resulting PEGylated STZ competes against biological TST, especially at lower concentrations. Cytotoxicity of increasing concentrations (1, 10, 25 or 50 µM) of STZ and/or (MeO-PEG-NH)10kDa-STZ was also evaluated for up 80 h by performing the MTT assay on human osteosarcoma Saos-2 cells, which express AR and are responsive to STZ. PEGylation mitigated cytotoxicity of STZ, by increasing the cell viability values, especially at higher drug concentrations. Furthermore, these results suggest that (MeO-PEG-NH)10kDa-STZ is a promising and reliable drug to be used in clinical conditions in which TST is required.

Overcoming Cancer Cell Drug Resistance by a Folic Acid Targeted Polymeric Conjugate of Buthionine Sulfoximine.

BACKGROUND: Glutathione (GSH), which is the predominant low molecular weight intracellular thiol in mammals, has multiple functions, such as those of protecting against oxidative stress and detoxifying endogenous and exogenous electrophiles. High GSH levels, which have been observed in various types of tumors, have been thought to contribute to the resistance of neoplastic cells to apoptotic stimuli triggered by pro-oxidant therapy. Although L-(S,R)-Buthionine Sulfoximine (BSO), a selective irreversible inhibitor of glutamate cysteine ligase, depletes GSH in vitro and in in vivo and sensitizes tumor cells to radiation and some cancer chemotherapeutics, its toxicity and short in vivo half-life have limited its application to combination anticancer therapies. OBJECTIVE: To demonstrate that a folate-targeted PEGylated BSO conjugate can sensitize cancer cells to a Reactive Oxygen Species (ROS)-generating anticancer agent by depleting GSH. METHODS: A novel folate-targeted PEGylated-BSO conjugate was synthesized and tested in combination with gemcitabine in human cell lines that over-express (HeLa) or do not express (A549) the folate receptor. RESULTS: The prepared folate-PEG-GFLG-BSO conjugate proved to be efficacious in reducing GSH levels and, when used in combination with the pro-oxidant drug gemcitabine, it enhanced drug activity in the cell line overexpressing the folate receptor. CONCLUSION: The folate-PEG-GFLG-BSO conjugate studied was found to be effective in sensitizing folatereceptor positive cancer cells to the ROS-generating drug gemcitabine.

Sclareol-loaded hyaluronan-coated PLGA nanoparticles: Physico-chemical properties and in vitro anticancer features.

Sclareol (labd­14­ene­8,13­diol), a phytochemical compound belonging to labdane-type diterpenes, has recently attracted noteworthy attention because of its peculiar pharmacological properties. The foremost obstacle to an efficacious application and use of this molecule is its unfavorable bioavailability due to its poor aqueous solubility. In this investigation sclareol was encapsulated within PLGA nanoparticles with the aim of favoring its administration in physiological media, increasing its anticancer activity and obtaining a stable colloidal formulation. These nanoparticles containing sclareol were characterized by a mean diameter of 100-150 nm, a narrow size distribution and a negative surface charge. The active compound was efficiently retained by the polymeric structure and did not induce any physical destabilization. The coating of the PLGA nanoparticles with hyaluronic acid (1.5 MDa) increased the antitumor efficacy of the encapsulated drug against human breast cancer cells expressing the hyaluronan receptors (MCF-7 and MDA-MB468) while a similar pharmacological effect was obtained on human colon carcinoma cells (CaCo-2). CLSM analysis demonstrated the intracellular localization of fluorescent nanosystems after 3 h incubation.

Mathematical Models as Tools to Predict the Release Kinetic of Fluorescein from Lyotropic Colloidal Liquid Crystals.

In this study, we investigated the release kinetic of fluorescein from colloidal liquid crystals made from monoglyceride and different non-ionic surfactants. The crystals were physicochemically characterized and the release experiments were carried out under the sink conditions, while mathematical models were described as extrapolations from solutions of the diffusion equation, in different initial and boundary conditions imposed by pharmaceutical formulations. The diffusion equation was solved using Laplace and Fourier transformed functions for release kinetics from infinite reservoirs in a semi-infinite medium. Solutions represents a general square root law and can be applied for the release kinetic of fluorescein from lyotropic colloidal liquid crystals. Akaike, Schwartz, and Imbimbo criteria were used to establish the appropriate mathematical model and the hierarchy of the performances of different models applied to the release experiments. The Fisher statistic test was applied to obtain the significance of differences among mathematical models. Differences of mathematical criteria demonstrated that small or no significant statistic differences were carried out between the various applied models and colloidal formulations. Phenomenological models were preferred over the empirical and semi-empirical ones. The general square root model shows that the diffusion-controlled release of fluorescein is the mathematical models extrapolated for lyotropic colloidal liquid crystals.

Druggability profile of stilbene-derived PPAR agonists: determination of physicochemical properties and PAMPA study.

PPAR agonists represent a new therapeutic opportunity for the prevention and treatment of neurodegenerative disorders, but their pharmacological success depends on favourable pharmacokinetic properties and capability to cross the BBB. In this study, we assayed some PPAR agonists previously synthesized by us for their physicochemical properties, with particular references to lipophilicity, solubility and permeability profiles, using the PAMPA. Although tested compounds showed high lipophilicity and low aqueous solubility, the results revealed a good overall druggability profile, encouraging further studies in the field of neurodegenerative diseases.

Polydocanol foam stabilized by liposomes: Supramolecular nanoconstructs for sclerotherapy.

Vascular pathology of the lower limbs is a widespread disease affecting the quality of life for more than 30% of the adult world population. Polydocanol foam is presently the main therapeutic option for treating varicosities, inflammation, and chronic disease which affect the vascular endothelium and blood vessels. Unfortunately, the commercial product contains detergents and surfactants which can provoke several side effects and decrease the efficacy of therapy. In an attempt to overcome these drawbacks, polydocanol foam was mixed with different liposomes before use. The resulting mixture was stable and generated supramolecular nanoconstructs, which may prevent the interaction of the components of the commercial polydocanol foam with the vascular endothelium. This effect depends on the presence of liposomes, which can induce polydocanol foam to change its structure from micelles to complex nanostructures, thus improving its stability. In this attempt, the physicochemical features of the resulting nanoconstructs were tested through dynamic- and multiple light scattering analyses, rheological studies and gel permeation chromatography, while the stability was tested in biological fluids. Our preliminary results showed that the nanoconstructs have some potential as therapeutic agents in sclerotherapy.

An insight of in vitro transport of PEGylated non-ionic surfactant vesicles (NSVs) across the intestinal polarized enterocyte monolayers.

PEGylated non-ionic surfactant-based vesicles (NSVs) are promising drug delivery systems for the local, oral and systemic administrations of therapeutics. The aim of this study was to test the cellular biocompatibility and transport of Nile Red-loaded NSVs (NR-NSVs) across the Caco-2-cell monolayers, which represent an in vitro model of human intestinal epithelium. The NR-NSVs assumed a spherical shape with a mean size of 140 nm, and a narrow size distribution. The NR-NSVs did not modify Caco-2 cell viability, which remained unaltered in vitro up to a concentration of 1 mM. The transport studies demonstrated that the NR-NSVs moved across the Caco-2 monolayers without affecting the transepithelial electrical resistance. These results were supported by flow cytometry analysis, which demonstrated that NR-NSVs were internalized inside the Caco-2 cells. Nanoparticle tracking and Transmission Electron Microscopy (TEM) analysis showed the presence of NR-NSVs in the basolateral side of the Caco-2 monolayers. TEM images also showed that NSVs were transported intact across the Caco-2 monolayers, thus demonstrating a predominant transcytosis mechanism of transport through endocytosis. The NSVs did not affect the integrity of the membrane barrier in vitro, and can potentially be used in clinics to increase the oral bioavailability and delivery of therapeutics.

Physicochemical characterization of pH-responsive and fusogenic self-assembled non-phospholipid vesicles for a potential multiple targeting therapy.

In order to obtain nanocarriers suitable for the delivery of drugs in the treatment of cancer, pH-responsive nanovesicles capable of facilitating fusion (fusogenic nanovesicles) were synthesized and then their physicochemical characteristics were modified. These nanovesicles were made by combining polysorbates having different physicochemical features with the aim of realizing multiple-targeting nanoformulations suitable for in vitro treatment of cancer cells. Tween21 and Tween80 were self-assembled at different molar concentrations resulting in pH-responsive fusogenic nanovesicles with an average size of less than 150nm, and a narrow size distribution (polydispersity index) value of less than 0.2. Hydrophobic and hydrophilic fluorescent probes were loaded inside the nanovesicles in order to study their pH-responsiveness and fusogenic properties and it was noted that this process did not modify their physicochemical features. The pH-responsiveness and fusogenic assay demonstrated that the nanovesicles containing Tween21 at different molar ratios were pH-responsive and interacted with a synthetic model of a biological membrane supplemented with Ca2+ in the incubation medium. Fifty percent (molar ratio) of Tween21 was replaced with Tween80, since Tween80 can promote the adsorption of apolipoproteins (A-E) onto the surfaces of nanovesicles without altering their pH-responsiveness or fusogenic properties. In fact this equivalent molar concentration of Tween21 and Tween80 also maintained their degree of interaction with the apolipoproteins (A-E). Doxorubicin hydrochloride-loaded nanovesicles were synthesized and physicochemically characterized in order to obtain nanoformulations suitable for anticancer treatment. The therapeutic nanovesicles showed physicochemical properties similar to those of empty nanoformulations, and maintained pH-responsiveness, fusogenic properties and targeting versus the apolipoproteins (A-E). The doxorubicin hydrochloride was loaded into the nanovesicles using both passive and pH gradient remote loading procedures. The latter provided the nanovesicles with an entrapment efficiency percentage of over 30%, which was much higher than the 10% that was obtained using the passive loading procedure. The entrapment efficiency improved up to 60% for the nanovesicles made from the same molar concentration of Tween21 and Tween80. The anticancer activity of doxorubicin hydrochloride-loaded nanovesicles was further tested in vitro using human neuroblastoma (SH-SY5Y) cells which respond to treatment with this chemotherapeutic drug, but the nanovesicles carrying it must cross the BBB by means of specific receptors before the drug can provide a therapeutic effect in vivo. The anticancer activity of these doxorubicin hydrochloride-loaded nanovesicles was time- and dosage- dependent, and the surfactant components making up the nanoformulations was also a determining factor in the efficiency of their activity. These nanovesicles could provide innovative nanotherapeutics for potential in vitro multidrug targeting therapy.

Interaction between PEG lipid and DSPE/DSPC phospholipids: An insight of PEGylation degree and kinetics of de-PEGylation.

The degree to which liposomes are PEGylated is the feature, which most influences the length of the presence of stealth liposomes in the bloodstream. In order to thoroughly investigate the maximum amount of DSPE-PEG2000 that can be used to stabilize stealth liposomes, these were synthesized at different concentrations of DSPE-PEG2000 and their physicochemical properties were investigated by using differential scanning calorimetry (DSC). The kinetics of PEGylation and de-PEGylation were performed by incubating non-stealth liposomes in a DSPE-PEG2000 suspension at different incubation times, and then analyzing the data using DSC and dynamic light scattering (DLS) techniques. The results demonstrated that DSPE-PEG2000 was self-assembled in the phospholipid bilayers, thus forming stealth liposomes. The different amounts of DSPE-PEG2000 in the bilayer triggered a de-PEGylation phenomenon, resulting in mixed nanoaggregates, which derived from the detergent-like properties of the PEGylated phospholipids.

Delivery of miR-34a by chitosan/PLGA nanoplexes for the anticancer treatment of multiple myeloma.

The encapsulation of miR-34a into chitosan/PLGA nanoparticles in order to obtain nanoplexes useful for the modulation of the biopharmaceutical features of the active compound was studied. The nanoplexes were obtained through nanoprecipitation and were characterized by a mean diameter of ~160 nm, a good size distribution and a positive surface charge. The structure of the nanoparticles allowed a high level of entrapment efficiency of the miR-34a and provided protection of the genetic material from the effects of RNase. A high degree of transfection efficiency of the nanoplexes and a significant in vitro antitumor effect against multiple myeloma cells was demonstrated. The therapeutic properties of the nanoplexes were evaluated in vivo against human multiple myeloma xenografts in NOD-SCID mice. The systemic injection of miR-34a mimic-loaded nanoparticles significantly inhibited tumor growth and translated into improved survival of the laboratory mice. RT-PCR analysis carried out on retrieved tumors demonstrated the presence of a high concentration of miR-34a mimics. The integrity of the nanoplexes remained intact and no organ toxicity was observed in treated animals.

Influence of the Supramolecular Micro-Assembly of Multiple Emulsions on their Biopharmaceutical Features and In vivo Therapeutic Response.

The ability of some surfactants to self-assemble in a water/oil bi-phase environment thus forming supramolecular structure leading to the formation of w/o/w multiple emulsions was investigated. The w/o/w multiple emulsions obtained by self-assembling (one-step preparation method) were compared with those prepared following the traditional two-step procedure. Methyl-nicotinate was used as a hydrophilic model drug. The formation of the multiple emulsion structure was evidenced by optical microscopy, which showed a mean size of the inner oil droplets of 6 µm and 10 µm for one-step and two-step multiple emulsions, respectively. The in vitrobiopharmaceutical features of the various w/o/w multiple emulsion formulations were evaluated by means of viscosimetry studies, drug release and in vitro percutaneous permeation experiments through human stratum corneum and viable epidermis membranes. The self-assembled multiple emulsions allowed a more gradual percutaneous permeation (a zero-order permeation rate) than the two-step ones. The in vivotopical carrier properties of the two different multiple emulsions were evaluated on healthy human volunteers by using the spectrophotometry of reflectance, an in vivonon invasive method. These multiple emulsion systems were also compared with conventional emulsion formulations. Our findings demonstrated that the multiple emulsions obtained by self-assembling were able to provide a more sustained drug delivery into the skin and hence a longer therapeutic action than two-step multiple emulsions and conventional emulsion formulations. Finally, our findings showed that the supramolecular micro-assembly of multiple emulsions was able to influence not only the biopharmaceutical characteristics but also the potential in vivotherapeutic response.

Synthesis and physico-chemical characterization of a ß-cyclodextrin conjugate for sustained release of Acyclovir.

We report the synthesis of an oligomeric prodrug of the antiviral agent Acyclovir (Acy) conjugated to ß-cyclodextrin (ß-CyD). The drug was selectively linked through a succinic spacer to one of the primary hydroxyl groups of ß-CyD by ester linkage in a 1:1 molar ratio. The conjugate was purified by semipreparative reverse-phase chromatography and characterized by FAB mass spectrometry and NMR experiments. The release of Acy from the conjugate was evaluated both in acidic and in neutral conditions and in the presence of porcine liver esterase. In all cases we observed the release of both free Acy and Acy succinate (AcySucc) at differing rates as a function of the hydrolysis conditions. In the presence of esterase the release of free Acy was favoured over AcySucc, showing a release rate of 100% of Acy within 7 days.

Aqueous-core PEG-coated PLA nanocapsules for an efficient entrapment of water soluble anticancer drugs and a smart therapeutic response.

Novel PEGylated PLA nanocapsules (PEG-AcPLA nanocapsules), loading high percentage of water soluble drugs have been formulated by using multiple emulsion technique without using conventional stabilizers. In particular, sodium deoxycholate hydrate has been used to obtain nanocapsules having a mean diameter of about 200 nm and a polydispersity index of ∼ 0.1. Gemcitabine hydrochloride (GEM) was used as a model of hydrophilic drug. GEM-loaded PEG-AcPLA nanocapsules demonstrated a high encapsulation efficacy and the drug-release followed a zero-order kinetic. MTT-assay evidenced an increased antitumor effect of GEM-loaded PEG-AcPLA nanocapsules compared to the free drug on different cancer cell lines and confocal laser scanning microscopy showed a significant improvement of cell interaction at 6h of incubation. In vivo anticancer activity of GEM-loaded PEG-AcPLA nanocapsules using two xenograft murine models of human solid tumors further supported the efficacy of this nano-drug, thus providing preliminary results about the potential clinical application of this innovative nanotherapeutic.

Polyaspartamide-doxorubicin conjugate as potential prodrug for anticancer therapy.

PURPOSE: To synthesize a new polymeric prodrug based on α,ß-poly(N-2-hydroxyethyl)(2-aminoethylcarbamate)-d,l-aspartamide copolymer bearing amine groups in the side chain (PHEA-EDA), covalently linked to the anticancer drug doxorubicin and to test its potential application in anticancer therapy. METHODS: The drug was previously derivatized with a biocompatible and hydrophilic linker, leading to a doxorubicin derivative highly reactive with amino groups of PHEA-EDA. The PHEA-EDA-DOXO prodrug was characterized in terms of chemical stability. The pharmacokinetics, biodistribution and cytotoxicity of the product was investigated in vitro and in vivo on human breast cancer MCF-7 and T47D cell lines and NOD-SCID mice bearing a MCF-7 human breast carcinoma xenograft. Data collected were compared to those obtained using free doxorubicin. RESULTS: The final polymeric product is water soluble and easily hydrolysable in vivo, due to the presence of ester and amide bonds along the spacer between the drug and the polymeric backbone. In vitro tests showed a retarded cytotoxic effect on tumor cells, whereas a significant improvement of the in vivo antitumor activity of PHEA-EDA-DOXO and a survival advantage of the treated NOD-SCID mice was evidenced, compared to that of free doxorubicin. CONCLUSIONS: The features of the PHEA-EDA-DOXO provide a potential protection of the drug from the plasmatic enzymatic degradation and clearance, an improvement of the blood pharmacokinetic parameters and a suitable body biodistribution. The data collected support the promising rationale of the proposed macromolecular prodrug PHEA-EDA-DOXO for further potential development and application in the treatment of solid cancer diseases.