Laura Catenacci

Albumin nanoparticles carrying cyclodextrins for nasal delivery of the anti-Alzheimer drug tacrine

Peroral administration of tacrine, the first acetylcholinestearse inhibitor licensed for the treatment of Alzheimers disease, is associated with low bioavailability, due to an extended first-pass methabolism, short elimination half-life and hepatotoxicity. Nasal drug delivery may reduce the degree of these problems. Tacrine hydrochloride nasal delivery is here investigated by means of albumin nanoparticles carrying beta cyclodextrin and two different beta cyclodextrin derivatives (hydroxypropyl beta cyclodextrin and sulphobutylether beta cyclodextrin). Bovine serum albumin nanoparticles were obtained using a coacervation method, followed by thermal cross-linking, starting from protein solution at alkaline pH. After preparation, nanoparticles were loaded by soaking from solutions of tacrine hydrochloride and lyophilised. Thermal analysis (differential scanning calorimetry and thermogravimetric analysis) supported by Fourier Transform Infrared Spectroscopy were performed in order to confirm protein cross-linking in nanosphere structure and possible drug/carrier interaction occurred after the loading process. Moreover, size, polydispersity, zeta potential and morphology of the nanoparticles were investigated as well as drug loading, mucoadhesion properties and ex-vivo drug permeation ability. Results indicate that all the nanoparticles presented a mean size and a polydispersity lower than 300nm and 0.33nm, respectively, were spherical shaped and negatively charged even after drug loading. Moreover, the presence of the different beta cyclodextrins in the polymeric network affected drug loading and could differently modulate nanoparticle mucoadhesiveness and drug permeation behaviour.

Wound dressings based on silver sulfadiazine solid lipid nanoparticles for tissue repairing.

The management of difficult to heal wounds can considerably reduce the time required for tissue repairing and promote the healing process, minimizing the risk of infection. Silver compounds, especially silver sulfadiazine (AgSD), are often used to prevent or to treat wound colonization, also in presence of antibiotic-resistant bacteria. However, AgSD has been shown to be cytotoxic in vitro toward fibroblasts and keratinocytes and consequently to retard wound healing in vivo. Recently, platelet lysate (PL) has been proposed in clinical practice for the healing of persistent lesions. The aim of the present work was the development of wound dressings based on AgSD loaded in solid lipid nanoparticles (SLNs), to be used in association with PL for the treatment for skin lesions. SLN were based on chondroitin sulfate and sodium hyaluronate, bioactive polymers characterized by well-known tissue repairing properties. The encapsulation of AgSD in SLN aimed at preventing the cytotoxic effect of the drug on normal human dermal fibroblasts (NHDFs) and at enabling the association of the drug with PL. SLN were loaded in wound dressings based on hydroxypropylmethyl cellulose (HPMC) or chitosan glutamate (CS glu). These polymers were chosen to obtain a sponge matrix with suitable elasticity and softness and, moreover, with good bioadhesive behavior on skin lesions. Dressings based on chitosan glutamate showed antimicrobial activity with and without PL. Even though further in vivo evaluation could be envisaged, chitosan based dressings demonstrated to be a suitable prototype for the treatment for skin lesions.

Novel mucoadhesive nasal inserts based on chitosan/hyaluronate polyelectrolyte complexes for peptide and protein delivery

OBJECTIVES The purpose of this study was the preparation and characterisation of mucoadhesive nasal inserts based on chitosan/hyaluronate polyelectrolyte complexes prepared at various pHs and at different molar ratios. METHODS A suspension of chitosan/hyaluronate complexes with or without the model drugs (vancomycin or insulin) was lyophilised into small inserts. Complexation yield, FT-IR spectra and thermogravimetric analysis were used to study the degree of interactive strength between polyions. In-vitro swelling, mucoadhesion and release tests were performed in order to investigate delivery of vancomycin and insulin in the nasal cavity. KEY FINDINGS The results indicated that the selection of complex preparative conditions allows modulation of insert swelling and mucoadhesion ability. Nasal inserts containing vancomycin or insulin had showed completely different drug release behaviour. CONCLUSIONS Chitosan/hyaluronate polyelectrolyte complexes can be used for the formulation of mucoadhesive nasal inserts for the delivery of peptide and protein drugs.

Identification of RC-33 as a potent and selective σ1 receptor agonist potentiating NGF-induced neurite outgrowth in PC12 cells. Part 2: g-scale synthesis, physicochemical characterization and in vitro metabolic stability.

Strong pharmacological evidences indicate that σ1 receptors are implicated in the pathophysiology of all major CNS disorders. In the last years our research group has conducted extensive studies aimed at discovering novel σ1 ligands and we recently selected (R/S)-RC-33 as a novel potent and selective σ1 receptor agonist. As continuation of our work in this field, here we report our efforts in the development of this new σ1 receptor agonist. Initially, we investigated the binding of (R) and (S) enantiomers of RC-33 to the σ1 receptor by in silico experiments. The close values of the predicted affinity of (R)-RC-33 and (S)-RC-33 for the protein evidenced the non-stereoselective binding of RC-33 to the σ1 receptor; this, in turn, supported further development and characterization of RC-33 in its racemic form. Subsequently, we set-up a scaled-up, optimized synthesis of (R/S)-RC-33 along with some compound characterization data (e.g., solubility in different media and solid state characterization by thermal analysis techniques). Finally, metabolic studies of RC-33 in different biological matrices (e.g., plasma, blood, and hepatic S9 fraction) of different species (e.g., rat, mouse, dog, and human) were performed. (R/S)-RC-33 is generally stable in all examined biological matrices, with the only exception of rat and human liver S9 fractions in the presence of NADPH. In such conditions, the compound is subjected to a relevant oxidative metabolism, with a degradation of approximately 65% in rat and 69% in human. Taken together, our results demonstrated that (R/S)-RC-33 is a highly potent, selective, metabolically stable σ1 agonist, a promising novel neuroprotective drug candidate.

Mesenchymal Stromal Cell Infusions as Rescue Therapy for Corticosteroid-Refractory Adult Autoimmune Enteropathy

Adult autoimmune enteropathy (AIE) is a rare cause of malabsorption syndrome unresponsive to dietary restriction. Its diagnostic hallmarks are small-bowel villous atrophy and antienterocyte autoantibodies. Therapy is based mainly on nutritional support and immunosuppression. We treated a 61-year-old woman with corticosteroid-refractory AIE and life-threatening malabsorption syndrome with systemic infusions of autologous, bone marrow-derived, mesenchymal stromal cells (MSCs) as rescue therapy. The MSCs were expanded ex vivo following a previously used Good Manufacturing Practice procedure, and 2 intravenous infusions of 1.8 × 10(6) MSCs/kg body weight were administered 2 weeks apart. Analysis of circulating and mucosal regulatory T-and B-cell numbers, and of serum and secretory immunoglobulin levels, was performed before and after treatment. The MSC infusions were safe and effective, leading to disappearance of disease hallmarks and recovery from the life-threatening condition. Increases in mucosal regulatory T-cell numbers and secretory immunoglobulin levels were also observed. The benefit, however, was transient, and a further MSC infusion resulted in the same short efficacy. This case encourages the use of MSCs to treat patients with life-threatening, corticosteroid-refractory AIE and suggests that MSC infusion can attenuate, albeit transiently, the autoimmune attack.

Inclusion of trans-resveratrol in methylated cyclodextrins: synthesis and solid-state structures

Summary The phytoalexin trans-resveratrol, 5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-1,3-benzenediol, is a well-known, potent antioxidant having a variety of possible biomedical applications. However, its adverse physicochemical properties (low stability, poor aqueous solubility) limit such applications and its inclusion in cyclodextrins (CDs) has potential for addressing these shortcomings. Here, various methods of the attempted synthesis of inclusion complexes between trans-resveratrol and three methylated cyclodextrins (permethylated α-CD, permethylated β-CD and 2,6-dimethylated β-CD) are described. Isolation of the corresponding crystalline 1:1 inclusion compounds enabled their full structure determination by X-ray analysis for the first time, revealing a variety of guest inclusion modes and unique supramolecular crystal packing motifs. The three crystalline inclusion complexes were also fully characterized by thermal analysis (hot stage microscopy, thermogravimetric analysis and differential scanning calorimetry). To complement the solid-state data, phase-solubility studies were conducted using a series of CDs (native and variously derivatised) to establish their effect on the aqueous solubility of trans-resveratrol and to estimate association constants for complex formation.

Stem cell-extracellular vesicles as drug delivery systems: New frontiers for silk/curcumin nanoparticles

The aim of this work was to develop a novel carrier-in-carrier system based on stem cell-extracellular vesicles loaded of silk/curcumin nanoparticles by endogenous technique. Silk nanoparticles were produced by desolvation method and curcumin has been selected as drug model because of its limited water solubility and poor bioavailability. Nanoparticles were stable, with spherical geometry, 100nm in average diameter and the drug content reached about 30%. Cellular uptake studies, performed on mesenchymal stem cells (MSCs), showed the accumulation of nanoparticles in the cytosol around the nuclear membrane, without cytotoxic effects. Finally, MSCs were able to release extracellular vesicles entrapping silk/curcumin nanoparticles. This combined biological-technological approach represents a novel class of nanosystems, combining beneficial effects of both regenerative cell therapies and pharmaceutical nanomedicine, avoiding the use of viable replicating stem cells.

A dry powder formulation from silk fibroin microspheres as a topical auto-gelling device

Abstract With the aim of establishing the formulation of a new hydrophilic auto-gelling medical device for biomedical applications, fibroin-based microspheres were prepared. The proposed microspheres were produced by a cost-effective and industrially scalable technique, such as the spray-drying. Spray-dried silk fibroin microspheres were obtained and the effects of different hydrophilic polymer on the process yield, microsphere morphology and conformation transition of fibroin were evaluated. The final auto-gelling formulations were obtained by adding calcium gluconate (as a calcium source for alginate crosslinking) to the prepared microspheres and tested by an in vitro gelling test. This study showed that the combination of fibroin with sodium alginate and poloxamer produced the most promising auto-gelling formulation for specific biomedical applications, such as the treatment of pressure ulcers.

Allogeneic hematopoietic stem cell transplantation may restore gluten tolerance in patients with celiac disease.

ABSTRACT We report on 2 patients affected by both celiac disease (CD) and &bgr;-thalassemia major who underwent successful myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) for the latter condition. After HSCT, the introduction of a gluten-containing diet did not cause the reappearance of clinical, serological, and histological markers of CD in up to 5 years of follow-up. After transplantation, in both patients, dendritic cells and regulatory FoxP3+T cells showed a recovery of normal values and no proliferative T-cell response upon gliadin stimulation was found. These data suggest that allogeneic HSCT may lead to induction of gluten tolerance in patients with CD.

Solid-state characterization of tacrine hydrochloride

The present study deals with the physicochemical characterization of solid forms of tacrine monohydrochloride (TCR), a centrally active reversible acetylcholinesterase inhibitor for treating the symptoms of mild to moderate Alzheimers disease, obtained by recrystallization of hot saturated solutions from different solvents. Recrystallization of the commercially available hydrate, TCR·H₂O, from water, hydroalcoholic solutions with ethanol, n-propanol, methanol and isopropanol (1:1, v/v) and isopropanol/water (8:2, v/v) afforded a new dihydrate phase TCR·2H₂O form I. The TCR samples obtained by desolvation of TCR·H₂O and TCR·2H₂O show temperature and melting enthalpy values very similar, thus confirming the existence of a unique anhydrous crystalline phase. Exposure of anhydrous TCR powder samples under different atmospheric conditions at room temperature, resulted in rehydration to TCR·H₂O at 32% relative humidity (RH), whereas at 100% RH a new solid form of TCR·2H₂O (TCR·2H₂O form II), i.e. a polymorph of the dihydrate isolated by recrystallization, was obtained. Differential scanning calorimetry (DSC), simultaneous thermogravimetric analysis (TGA/DSC), and thermo optical analysis (TOA) with support from X-ray powder diffractometry (PXRD) and Fourier transform infrared spectroscopy (FT-IR), were used for the characterization of the isolated solid forms of TCR and monitoring the water uptake of anhydrous TCR.